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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 426 journals)
Showing 1 - 200 of 265 Journals sorted alphabetically
AAS Open Research     Open Access  
ABC Journal of Advanced Research     Open Access  
Accountability in Research: Policies and Quality Assurance     Hybrid Journal   (Followers: 17)
Acta Materialia Transilvanica     Open Access  
Acta Nova     Open Access  
Acta Scientifica Malaysia     Open Access  
Acta Scientifica Naturalis     Open Access   (Followers: 2)
Adıyaman University Journal of Science     Open Access  
Advanced Science     Open Access   (Followers: 12)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 3)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advances in Research     Open Access  
Advances in Science and Technology     Full-text available via subscription   (Followers: 16)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 7)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 4)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 2)
American Academic & Scholarly Research Journal     Open Access   (Followers: 4)
American Journal of Applied Sciences     Open Access   (Followers: 21)
American Journal of Humanities and Social Sciences     Open Access   (Followers: 10)
American Scientist     Full-text available via subscription   (Followers: 12)
ANALES de la Universidad Central del Ecuador     Open Access   (Followers: 1)
Anales del Instituto de la Patagonia     Open Access  
Applied Mathematics and Nonlinear Sciences     Open Access  
Apuntes de Ciencia & Sociedad     Open Access  
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 1)
Archives Internationales d'Histoire des Sciences     Partially Free   (Followers: 5)
Archives of Current Research International     Open Access  
ARO. The Scientific Journal of Koya University     Open Access  
ARPHA Conference Abstracts     Open Access   (Followers: 1)
ARPHA Proceedings     Open Access  
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access  
Asian Journal of Advanced Research and Reports     Open Access   (Followers: 1)
Asian Journal of Applied Science and Engineering     Open Access  
Asian Journal of Scientific Research     Open Access   (Followers: 2)
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 5)
Australian Field Ornithology     Full-text available via subscription   (Followers: 2)
Australian Journal of Social Issues     Hybrid Journal   (Followers: 7)
Avrasya Terim Dergisi     Open Access  
Bangladesh Journal of Scientific Research     Open Access  
Beni-Suef University Journal of Basic and Applied Sciences     Open Access  
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 10)
Berkeley Scientific Journal     Full-text available via subscription  
BIBECHANA     Open Access  
BibNum     Open Access  
Bilge International Journal of Science and Technology Research     Open Access   (Followers: 1)
Bioethics Research Notes     Full-text available via subscription   (Followers: 16)
BJHS Themes     Open Access  
Black Sea Journal of Engineering and Science     Open Access  
Borneo Journal of Resource Science and Technology     Open Access  
Bulletin de la Société Royale des Sciences de Liège     Open Access  
Bulletin of the National Research Centre     Open Access  
Butlletí de la Institució Catalana d'Història Natural     Open Access  
Central European Journal of Clinical Research     Open Access  
Chain Reaction     Full-text available via subscription  
Ciencia Amazónica (Iquitos)     Open Access  
Ciencia en Desarrollo     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia Ergo Sum     Open Access  
Ciência ET Praxis     Open Access  
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Citizen Science : Theory and Practice     Open Access   (Followers: 1)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Applied Sciences     Open Access  
Comunicata Scientiae     Open Access  
ConCiencia     Open Access  
Conference Papers in Science     Open Access  
Configurations     Full-text available via subscription   (Followers: 11)
COSMOS     Hybrid Journal   (Followers: 1)
Crea Ciencia Revista Científica     Open Access  
Cuadernos de Investigación UNED     Open Access  
Current Issues in Criminal Justice     Hybrid Journal   (Followers: 14)
Current Research in Geoscience     Open Access   (Followers: 6)
Dalat University Journal of Science     Open Access  
Data     Open Access   (Followers: 4)
Data Curation Profiles Directory     Open Access   (Followers: 4)
Dhaka University Journal of Science     Open Access  
Dharmakarya     Open Access  
Diálogos Interdisciplinares     Open Access  
Digithum     Open Access   (Followers: 2)
Discover Sustainability     Open Access   (Followers: 2)
Einstein (São Paulo)     Open Access  
Ekaia : EHUko Zientzia eta Teknologia aldizkaria     Open Access  
Elkawnie : Journal of Islamic Science and Technology     Open Access  
Emergent Scientist     Open Access  
Enhancing Learning in the Social Sciences     Open Access   (Followers: 6)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Entramado     Open Access  
Entre Ciencia e Ingeniería     Open Access  
Epiphany     Open Access   (Followers: 1)
Estação Científica (UNIFAP)     Open Access  
Ethiopian Journal of Education and Sciences     Open Access   (Followers: 5)
Ethiopian Journal of Science and Technology     Open Access  
Ethiopian Journal of Sciences and Sustainable Development     Open Access  
European Online Journal of Natural and Social Sciences     Open Access   (Followers: 4)
European Scientific Journal     Open Access   (Followers: 2)
Evidência - Ciência e Biotecnologia - Interdisciplinar     Open Access  
Exchanges : the Warwick Research Journal     Open Access   (Followers: 1)
Experimental Results     Open Access  
Extensionismo, Innovación y Transferencia Tecnológica     Open Access  
Facets     Open Access  
Fides et Ratio : Revista de Difusión Cultural y Científica     Open Access  
Fırat University Turkish Journal of Science & Technology     Open Access  
Fontanus     Open Access  
Forensic Science Policy & Management: An International Journal     Hybrid Journal   (Followers: 239)
Frontiers for Young Minds     Open Access  
Frontiers in Climate     Open Access   (Followers: 3)
Frontiers in Science     Open Access   (Followers: 1)
Fundamental Research     Open Access   (Followers: 4)
Futures & Foresight Science     Hybrid Journal   (Followers: 2)
Gaudium Sciendi     Open Access  
Gazi University Journal of Science     Open Access  
Ghana Studies     Full-text available via subscription   (Followers: 14)
Global Journal of Pure and Applied Sciences     Full-text available via subscription  
Global Journal of Science Frontier Research     Open Access   (Followers: 1)
Globe, The     Full-text available via subscription   (Followers: 3)
HardwareX     Open Access  
Heidelberger Jahrbücher Online     Open Access  
Heliyon     Open Access  
Himalayan Journal of Science and Technology     Open Access  
History of Science and Technology     Open Access   (Followers: 1)
Hoosier Science Teacher     Open Access  
Impact     Open Access   (Followers: 1)
Indian Journal of History of Science     Hybrid Journal  
Indonesian Journal of Fundamental Sciences     Open Access  
Indonesian Journal of Science and Mathematics Education     Open Access   (Followers: 1)
Indonesian Journal of Science and Technology     Open Access  
Ingenieria y Ciencia     Open Access   (Followers: 1)
Innovare : Revista de ciencia y tecnología     Open Access  
Integrated Research Advances     Open Access  
Interciencia     Open Access  
Interface Focus     Full-text available via subscription  
International Annals of Science     Open Access  
International Archives of Science and Technology     Open Access  
International Journal of Academic Research in Business, Arts & Science     Open Access  
International Journal of Advanced Multidisciplinary Research and Review     Open Access  
International Journal of Applied Science     Open Access  
International Journal of Basic and Applied Sciences     Open Access   (Followers: 1)
International Journal of Computational and Experimental Science and Engineering (IJCESEN)     Open Access  
International Journal of Culture and Modernity     Open Access  
International Journal of Engineering, Science and Technology     Open Access  
International Journal of Engineering, Technology and Natural Sciences     Open Access  
International Journal of Innovation and Applied Studies     Open Access   (Followers: 3)
International Journal of Innovative Research and Scientific Studies     Open Access   (Followers: 1)
International Journal of Network Science     Hybrid Journal   (Followers: 3)
International Journal of Recent Contributions from Engineering, Science & IT     Open Access  
International Journal of Research in Science     Open Access   (Followers: 1)
International Journal of Science & Emerging Technologies     Open Access   (Followers: 1)
International Journal of Social Sciences and Management     Open Access   (Followers: 2)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 6)
International Letters of Social and Humanistic Sciences     Open Access  
International Scientific and Vocational Studies Journal     Open Access  
InterSciencePlace     Open Access  
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Investigacion y Ciencia     Open Access   (Followers: 1)
Iranian Journal of Science and Technology, Transactions A : Science     Hybrid Journal  
iScience     Open Access   (Followers: 1)
Issues in Science & Technology     Free   (Followers: 7)
Ithaca : Viaggio nella Scienza     Open Access  
Jaunujų mokslininkų darbai     Open Access  
Journal de la Recherche Scientifique de l'Universite de Lome     Full-text available via subscription  
Journal of Chromatography & Separation Techniques     Open Access   (Followers: 10)
Journal of Advanced Research     Open Access   (Followers: 2)
Journal of Al-Qadisiyah for Pure Science     Open Access  
Journal of Alasmarya University     Open Access  
Journal of Analytical Science & Technology     Open Access   (Followers: 4)
Journal of Applied Science and Technology     Full-text available via subscription   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 1)
Journal of Big History     Open Access   (Followers: 3)
Journal of Composites Science     Open Access   (Followers: 3)
Journal of Deliberative Mechanisms in Science     Open Access  
Journal of Diversity Management     Open Access   (Followers: 4)
Journal of Indian Council of Philosophical Research     Hybrid Journal  
Journal of Institute of Science and Technology     Open Access  
Journal of Integrated Science and Technology     Open Access  
Journal of Kerbala University     Open Access  
Journal of King Saud University - Science     Open Access  
Journal of Mathematical and Fundamental Sciences     Open Access  
Journal of Natural Sciences and Mathematics Research     Open Access  
Journal of Natural Sciences Research     Open Access   (Followers: 1)
Journal of Negative and No Positive Results     Open Access  
Journal of Responsible Technology     Open Access  
Journal of Science (JSc)     Open Access  
Journal of Science and Engineering     Open Access  
Journal of Science and Technology     Open Access   (Followers: 2)
Journal of Science and Technology     Open Access   (Followers: 1)
Journal of Science and Technology (Ghana)     Open Access   (Followers: 3)
Journal of Science and Technology Policy Management     Hybrid Journal   (Followers: 1)
Journal of Science Foundation     Open Access   (Followers: 1)
Journal of Science of the University of Kelaniya Sri Lanka     Open Access  
Journal of Scientific Research     Open Access  
Journal of Scientific Research and Reports     Open Access  
Journal of Scientometric Research     Open Access   (Followers: 19)
Journal of Shanghai Jiaotong University (Science)     Hybrid Journal  
Journal of Social Science Research     Open Access   (Followers: 2)
Journal of Taibah University for Science     Open Access  
Journal of the Asiatic Society of Bangladesh, Science     Open Access  

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Journal of Composites Science
Number of Followers: 3  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2504-477X
Published by MDPI Homepage  [78 journals]
  • J. Compos. Sci., Vol. 6, Pages 32: A Review of Nanocarbon-Based Solutions
           for the Structural Health Monitoring of Composite Parts Used in Renewable
           Energies

    • Authors: Antoine Lemartinel, Mickael Castro, Olivier Fouché, Julio-César De-Luca, Jean-François Feller
      First page: 32
      Abstract: The growing demands for electrical energy, especially renewable, is boosting the development of wind turbines equipped with longer composite blades. To reduce the maintenance cost of such huge composite parts, the structural health monitoring (SHM) is an approach to anticipate and/or follow the structural behaviour along time. Apart from the development of traditional non-destructive testing methods, in order to reduce the use of intrusive instrumentation there is a growing interest for the development of “self-sensing materials”. An interesting route to achieve this, can be to introduce carbon nanofillers such as nanotubes (CNT) in the composite structures, which enables to create systems that are sensitive to both strain and damage. This review aims at updating the state of the art of this topic so far. A first overview of the existing SHM techniques for thermoset based wind turbine blades composites is presented. Then, the use of self-sensing materials for strain and damage sensing is presented. Different strategies are overviewed and discussed, from the design of conductive composites such as carbon fibres reinforced polymers, to the elaboration of conductive nano-reinforced polymer composites. The origins of sensing mechanisms along with the percolation theory applied to nanofillers dispersed in polymer matrices are also detailed.
      Citation: Journal of Composites Science
      PubDate: 2022-01-19
      DOI: 10.3390/jcs6020032
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 33: Modeling Flexural Failure in
           Carbon-Fiber-Reinforced Polymer Composites

    • Authors: Thiago de Sousa Burgani, Seyedhamidreza Alaie, Mehran Tehrani
      First page: 33
      Abstract: Flexural testing provides a rapid and straightforward assessment of fiber-reinforced composites’ performance. In many high-strength composites, flexural strength is higher than compressive strength. A finite-element model was developed to better understand this improvement in load-bearing capability and to predict the flexural strength of three different carbon-fiber-reinforced polymer composite systems. The model is validated against publicly available experimental data and verified using theory. Different failure criteria are evaluated with respect to their ability to predict the strength of composites under flexural loading. The Tsai–Wu criterion best explains the experimental data. An expansion in compressive stress limit for all three systems was observed and is explained by the compression from the loading roller and Poisson’s effects.
      Citation: Journal of Composites Science
      PubDate: 2022-01-19
      DOI: 10.3390/jcs6020033
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 34: Assessing Failure in Steel
           Cable-Reinforced Rubber Belts Using Multi-Scale FEM Modelling

    • Authors: Siegfried Martin Frankl, Martin Pletz, Alfred Wondracek, Clara Schuecker
      First page: 34
      Abstract: This work introduces a finite element model of a steel cable-reinforced conveyor belt to accurately compute stresses in the splice. In the modelled test rig, the belt runs on two drums and is loaded with a cyclic longitudinal force. An explicit solver is used to efficiently handle the high number of elements and contact conditions. This, however, introduces some issues of dynamics in the model, which are subsequently solved: (a) the longitudinal load is applied with a smooth curve and damping is introduced in the beginning of the simulation, (b) residual stresses are applied in regions of the belt that are initially bent around the drums, and (c) supporting drums are introduced at the start of the simulation to hinder oscillations of the belt at low applied forces. To accurately capture the tensile and bending stiffness of the cables, they are modelled by a combination of solid and beam elements. The results show that numerical artefacts can be reduced to an acceptable extent. In the region of highest stresses, the displacements are additionally mapped onto a submodel with a smaller mesh size. The results show that, for the investigated belt, the local maximum principal stresses significantly increase when this region of highest stresses comes into contact with, and is bent by, the drum. Therefore, it is essential to also consider the belt’s bending to predict failure in such applications.
      Citation: Journal of Composites Science
      PubDate: 2022-01-20
      DOI: 10.3390/jcs6020034
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 35: Microstructure-Free Finite Element
           Modeling for Elasticity Characterization and Design of Fine-Particulate
           Composites

    • Authors: Yunhua Luo
      First page: 35
      Abstract: The microstructure-based finite element modeling (MB-FEM) of material representative volume element (RVE) is a widely used tool in the characterization and design of various composites. However, the MB-FEM has a number of deficiencies, e.g., time-consuming in the generation of a workable geometric model, challenge in achieving high volume-fractions of inclusions, and poor quality of finite element mesh. In this paper, we first demonstrate that for particulate composites the particle inclusions have homogeneous distribution and random orientation, and if the ratio of particle characteristic length to RVE size is adequately small, elastic properties characterized from the RVE are independent of particle shape and size. Based on this fact, we propose a microstructure-free finite element modeling (MF-FEM) approach to eliminate the deficiencies of the MB-FEM. The MF-FEM first generates a uniform mesh of brick elements for the RVE, and then a number of the elements, with their total volume determined by the desired volume fraction of inclusions, is randomly selected and assigned with the material properties of the inclusions; the rest of the elements are set to have the material properties of the matrix. Numerical comparison showed that the MF-FEM has a similar accuracy as the MB-FEM in the predicted properties. The MF-FEM was validated against experimental data reported in the literature and compared with the widely used micromechanical models. The results show that for a composite with small contrast of phase properties, the MF-FEM has excellent agreement with both the experimental data and the micromechanical models. However, for a composite that has large contrast of phase properties and high volume-fraction of inclusions, there exist significant differences between the MF-FEM and the micromechanical models. The proposed MF-FEM may become a more effective tool than the MB-FEM for material engineers to design novel composites.
      Citation: Journal of Composites Science
      PubDate: 2022-01-20
      DOI: 10.3390/jcs6020035
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 36: Uniaxial Compressive Behavior of
           AA5083/SiC Co-Continuous Ceramic Composite Fabricated by Gas Pressure
           Infiltration for Armour Applications

    • Authors: Achuthamenon Sylajakumari Prasanth, Vijayan Krishnaraj, Jayakrishnan Nampoothiri, Ramalingam Sindhumathi, Mohamed Raeez Akthar Sadik, Juan Pablo Escobedo, Krishna Shankar
      First page: 36
      Abstract: A novel approach of a gas pressure infiltration technique is presented for the synthesis of Co-Continuous Ceramic Composite (C4). SiC foams of varying pore sizes were infiltrated with aluminium AA5083. Optical examination revealed that the SiC foams contained open cells with a network of triangular voids. The number of pores-per-inch (PPI) in the foams was found to depend on the strut thickness and pore diameter. The compressive strengths of two foam configurations, 10 and 20 PPI, were estimated to lie between 1–2 MPa. After infiltration, the compressive yield strength of the resulting C4 was observed to increase to 126 MPa and 120 MPa, respectively, for the 10 and 20 PPI C4. Additionally, the infiltration of ceramic foam with the AA5083 alloy resulted in an increase in strength of 58–100 times when compared with plain ceramic foam. The failure modes of the composites in compression were analyzed by crack propagation and determining the type of failure. The study revealed that shear failure and vertical splitting were the predominant mechanisms of compression failure, and that the fabricated C4 is advantageous in mechanical properties compared to the plain ceramic foam. This study, therefore, suggests the use of C4 composites in armour applications.
      Citation: Journal of Composites Science
      PubDate: 2022-01-20
      DOI: 10.3390/jcs6020036
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 37: Effect of Defects Part I: Degradation
           of Constitutive Coefficients as an Input to the Composite Failure Model
           with Microvoids and Porosity

    • Authors: Vahid Tavaf, Sourav Banerjee
      First page: 37
      Abstract: It is always challenging to provide appropriate material properties for a composite progressive failure model. The nonstandard percentage reduction method that is commonly used to degrade the material constants with micro-scale defects generates tremendous uncertainty in failure prediction. The constitutive matrix is composed of multiple material constants. It is not necessary that all constants degrade either equally or linearly due to a certain state of material defects. With this very concern in mind, this article presents a guideline for using a quantified perturbation for each coefficient appropriately. It also presents distribution of effective material properties (EMPs) in unidirectional composite materials with different states of defects such as voids. Irrespective of resin transfer molding (RTM) or chemical vapor infiltration (CVI) processes, manufacturers’ defects such as voids of different shapes and sizes are the most common that occur in composite materials. Hence, it is important to quantify the ‘effects of defects’ void content herein on each material coefficient and EMP. In this article, stochastically distributed void parameters such as the void content by percent, size, shape, and location are considered. Void diameters and shapes were extracted from scanning acoustic microscope (SAM) images of 300,000 cycles of a fatigued composite. The EMPs were calculated by considering unit cells, homogenization techniques, and micromechanical concepts. The periodic boundary conditions were applied to unit cells to calculate the EMPs. The result showed that EMPs were degraded even when there was a small percentage of the void content. More importantly, the constitutive coefficients did not degrade equally but had a definitive pattern.
      Citation: Journal of Composites Science
      PubDate: 2022-01-20
      DOI: 10.3390/jcs6020037
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 38: The Role of Fibre Length on the Fatigue
           Failure of Injection-Moulded Composites at Elevated Temperatures under a
           Range of Axial Loading Conditions

    • Authors: Trevor Sabiston, Bin Li, Waqas Muhammad, Jidong Kang, Carlos Engler-Pinto
      First page: 38
      Abstract: The effect of fibre length distribution on the fatigue behaviour of an injection-moulded PA66 carbon fibre composite is investigated. Two materials, short carbon fibre with a mean length of 100 microns, and long carbon fibre with a mean length of 580 microns, are subjected to fully reversed fatigue loading at room temperature and three stress ratios at 120 °C. The fatigue results are compared, and fracture surfaces are analyzed to determine the differing failure modes between the materials and loading conditions. At 120 °C, the fibre length has a significant effect on the fatigue behaviour with order of magnitudes of different fatigue life for a given stress amplitude during tensile fatigue loading. Under tensile loading, fatigue failure initates as fibre matrix debonding with pits present due to end effects in the short carbon fibre material. Under compression–compression loading, the fatigue life is matrix-dominated and should be treated as a maximum stress failure. Under this loading, a smooth crack propagates across the sample with buckling as the final failure mode.
      Citation: Journal of Composites Science
      PubDate: 2022-01-20
      DOI: 10.3390/jcs6020038
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 39: Study of Graphene Epoxy/Nanoplatelets
           Thin Films Subjected to Aging in Corrosive Environments

    • Authors: Bellucci
      First page: 39
      Abstract: The corrosion of metallic devices and degradation of plastic materials are a cause of great concern for companies and countries’ economies; it is necessary to contrast these phenomena by studying innovative methodologies and techniques. A simple solution lies in the realization of materials that can resist corrosive environments and be used as coatings to prevent, or at least delay, deterioration. The purpose of this work was to study the behavior of an epoxy resin, in thin film form, exposed to corrosive chemicals. In particular, the samples were subjected to aging of 31 days in dilute sulfuric acid (H2SO4) and in an aqueous solution of potassium chloride (KCl). Subsequently, thin films of Epoxy/graphene nanoplatelets (GNP) composite material have been subjected to the same conditions: it was investigated how these samples respond to the corrosive environment. We found that the addition of carbonaceous nanofillers prolongs in time the ability of the material to resist the attack of chemical agents.
      Citation: Journal of Composites Science
      PubDate: 2022-01-22
      DOI: 10.3390/jcs6020039
      Issue No: Vol. 6, No. 2 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 15: A Review on Synthesis Methods of
           Phyllosilicate- and Graphene-Filled Composite Hydrogels

    • Authors: Sayan Ganguly, Shlomo Margel
      First page: 15
      Abstract: This review discusses, in brief, the various synthetic methods of two widely-used nanofillers; phyllosilicate and graphene. Both are 2D fillers introduced into hydrogel matrices to achieve mechanical robustness and water uptake behavior. Both the fillers are inserted by physical and chemical gelation methods where most of the chemical gelation, i.e., covalent approaches, results in better physical properties compared to their physical gels. Physical gels occur due to supramolecular assembly, van der Waals interactions, electrostatic interactions, hydrophobic associations, and H-bonding. For chemical gelation, in situ radical triggered gelation mostly occurs.
      Citation: Journal of Composites Science
      PubDate: 2022-01-01
      DOI: 10.3390/jcs6010015
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 16: 3D Printing under High Ambient
           Pressures and Improvement of Mechanical Properties of Printed Parts

    • Authors: Yousuf Pasha Shaik, Jens Schuster, Harshavardhan Reddy Katherapalli, Aarif Shaik
      First page: 16
      Abstract: Contrary to other polymer processing methods, additive manufacturing processes do not require any pressure during the consolidation of layers. This study investigates the effect of high ambient pressure on the consolidation of layers during the FDM process and their analysis of mechanical properties. An experimental setup was arranged, consisting of a 3D printer integrated into a customized Autoclave, to achieve high strength properties for 3D printed parts as like injection-molded specimens. The autoclave can maintain 135 bar of pressure and a maximum temperature of 185 °C. 3D printing with PLA was carried out at 0 bar, 5 bar, and 10 bar. Tensile, flexural, and Charpy tests were conducted on printed specimens, and the effect of pressure and temperature on 3D-printed samples were analyzed. It could be shown that autoclave preheating before printing and autoclave pressure during printing improves the consolidation of layers immensely. The pressure inside the autoclave provokes a more intimate contact between the layer surfaces and results in higher mechanical properties such as yield strength, Young’s modulus, and impact strength. The properties could be raised 100%.
      Citation: Journal of Composites Science
      PubDate: 2022-01-05
      DOI: 10.3390/jcs6010016
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 17: A SiO2/pHEMA-Based Polymer-Infiltrated
           Ceramic Network Composite for Dental Restorative Materials

    • Authors: Hiroshi Ikeda, Yohei Kawajiri, Minako Kibune Sodeyama, Haruka Takesue Yano, Yuki Nagamatsu, Chihiro Masaki, Ryuji Hosokawa, Hiroshi Shimizu
      First page: 17
      Abstract: SiO2-poly(2-hydroxyethyl methacrylate) (pHEMA)-based composites have been widely used as biomaterials owing to their biocompatibility. However, they have not yet been applied as tooth restorative materials because of their poor mechanical properties. In the present paper, we develop a novel SiO2/pHEMA-based composite with a polymer-infiltrated network (PICN) structure for use in dental restorative materials. A mixture of SiO2 nanoparticles and a poly(vinyl alcohol) binder was sintered at 950 °C to fabricate a porous SiO2 block. A monomer mixture containing 70 wt%-HEMA/30 wt%-ethylene glycol dimethacrylate and a benzoyl peroxide initiator was infiltrated into the porous SiO2 block and heat-polymerized to fabricate the SiO2/pHEMA-based composite with a PICN structure. The composite was characterized according to its mechanical properties, surface free energy, and bonding properties with a dental adhesive. The flexural strength was 112.5 ± 18.7 MPa, the flexural modulus was 13.6 ± 3.4 GPa, and the Vickers hardness was 168.2 ± 16.1, which are similar values to human teeth. The surface free energy of the polar component of the composite was 19.6 ± 2.5 mN/m, suggesting that this composite has an active surface for bonding with the adhesive. The composite bonded well to the adhesive, in the presence of a silane coupling agent. The SiO2/pHEMA-based composite was demonstrated to be a potential candidate for dental restorative materials.
      Citation: Journal of Composites Science
      PubDate: 2022-01-05
      DOI: 10.3390/jcs6010017
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 18: A Cost Model for 3D Woven Preforms

    • Authors: James Clarke, Alistair McIlhagger, Dorian Dixon, Edward Archer, Glenda Stewart, Roy Brelsford, John Summerscales
      First page: 18
      Abstract: Lack of cost information is a barrier to acceptance of 3D woven preforms as reinforcements for composite materials, compared with 2D preforms. A parametric, resource-based technical cost model (TCM) was developed for 3D woven preforms based on a novel relationship equating manufacturing time and 3D preform complexity. Manufacturing time, and therefore cost, was found to scale with complexity for seventeen bespoke manufactured 3D preforms. Two sub-models were derived for a Weavebird loom and a Jacquard loom. For each loom, there was a strong correlation between preform complexity and manufacturing time. For a large, highly complex preform, the Jacquard loom is more efficient, so preform cost will be much lower than for the Weavebird. Provided production is continuous, learning, either by human agency or an autonomous loom control algorithm, can reduce preform cost for one or both looms to a commercially acceptable level. The TCM cost model framework could incorporate appropriate learning curves with digital twin/multi-variate analysis so that cost per preform of bespoke 3D woven fabrics for customised products with low production rates may be predicted with greater accuracy. A more accurate model could highlight resources such as tooling, labour and material for targeted cost reduction.
      Citation: Journal of Composites Science
      PubDate: 2022-01-05
      DOI: 10.3390/jcs6010018
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 19: Integrating Soft Hydrogel with
           Nanostructures Reinforces Stem Cell Adhesion and Differentiation

    • Authors: Bohan Yin, Hongrong Yang, Mo Yang
      First page: 19
      Abstract: Biophysical cues can regulate stem cell behaviours and have been considered as critical parameters of synthetic biomaterials for tissue engineering. In particular, hydrogels have been utilized as promising biomimetic and biocompatible materials to emulate the microenvironment. Therefore, well-defined mechanical properties of a hydrogel are important to direct desirable phenotypes of cells. Yet, limited research pays attention to engineering soft hydrogel with improved cell adhesive property, which is crucial for stem cell differentiation. Herein, we introduce silica nanoparticles (SiO2 NPs) onto the surface of methacrylated hyaluronic (MeHA) hydrogel to manipulate the presentation of cell adhesive ligands (RGD) clusters, while remaining similar bulk mechanical properties (2.79 ± 0.31 kPa) to that of MeHA hydrogel (3.08 ± 0.68 kPa). RGD peptides are either randomly decorated in the MeHA hydrogel network or on the immobilized SiO2 NPs (forming MeHA–SiO2). Our results showed that human mesenchymal stem cells exhibited a ~1.3-fold increase in the percentage of initial cell attachment, a ~2-fold increase in cell spreading area, and enhanced expressions of early-stage osteogenic markers (RUNX2 and alkaline phosphatase) for cells undergoing osteogenic differentiation with the osteogenic medium on MeHA–SiO2 hydrogel, compared to those cultured on MeHA hydrogel. Importantly, the cells cultivated on MeHA–SiO2 expressed a ~5-fold increase in nuclear localization ratio of the yes-associated protein, which is known to be mechanosensory in stem cells, compared to the cells cultured on MeHA hydrogel, thereby promoting osteogenic differentiation of stem cells. These findings demonstrate the potential use of nanomaterials into a soft polymeric matrix for enhanced cell adhesion and provide valuable guidance for the rational design of biomaterials for implantation.
      Citation: Journal of Composites Science
      PubDate: 2022-01-06
      DOI: 10.3390/jcs6010019
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 20: Chemical Supercritical Fluid
           Infiltration of Pyrocarbon with Thermal Gradients: Deposition Kinetics and
           Multiphysics Modeling

    • Authors: Gerard L. Vignoles, Gaëtan Talué, Quentin Badey, Alain Guette, René Pailler, Yann Le Petitcorps, Laurence Maillé
      First page: 20
      Abstract: The chemical supercritical fluid infiltration process is a recent variation of the chemical vapor infiltration (CVI) process that allows rapid and efficient manufacturing of ceramic-matrix composites (CMCs), albeit still needing optimization. This article proposes a quantitative assessment of the process dynamics through experiments and modeling. The kinetics of carbon deposition were determined through two sets of experiments: CVD on a single filament at pressures between 10 and 50 bar and infiltration at pressures ranging between 50 and 120 bar. The CVI experiments were conducted under important thermal gradients and were interpreted using a model-based reconstitution of these gradients. We found that (i) the kinetic law has to incorporate the potential effect of the reverse reaction (i.e., etching of C by H2); (ii) the activation energy and pre-exponential factor both decrease with pressure up to 50 bar, then remain roughly constant, and (iii) although the apparent activation energy is modest, a favorable situation occurs in which an infiltration front builds up and travels from the hottest to the coldest part of the preform due to the presence of sufficient heat flux. A numerical simulation of the process, based on the solution of momentum, heat, and mass balance equations, fed with appropriate laws for the effective transfer properties of the porous medium and their evolution with infiltration progress, was performed and validated by comparing the simulated and actual infiltration profiles.
      Citation: Journal of Composites Science
      PubDate: 2022-01-07
      DOI: 10.3390/jcs6010020
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 21: FEM-Validated Optimal Design of
           Laminate Process Parameters Based on Improved Genetic Algorithm

    • Authors: Xing Mou, Zhiqiang Shen, Honghao Liu, Hui Xv, Xianzhao Xia, Shijun Chen
      First page: 21
      Abstract: In tape placement process, the laying angle and laying sequence of laminates have proven their significant effects on the mechanical properties of carbon fibre reinforced composite material, specifically, laminates. In order to optimise these process parameters, an optimisation algorithm is developed based on the principles of genetic algorithms for improving the precision of traditional genetic algorithms and resolving the premature phenomenon in the optimisation process. Taking multi-layer symmetrically laid carbon fibre laminates as the research object, this algorithm adopts binary coding to conduct the optimisation of process parameters and mechanical analysis with the laying angle as the design variable and the strength ratio R as the response variable. A case study was conducted and its results were validated by the finite element analyses. The results show that the stresses before and after optimisation are 116.0 MPa and 100.9 MPa, respectively, with a decrease of strength ratio by 13.02%. The results comparison indicates that, in the iterative process, the search range is reduced by determining the code and location of important genes, thereby reducing the computational workload by 21.03% in terms of time consumed. Through multiple calculations, it validates that “gene mutation” is an indispensable part of the genetic algorithm in the iterative process.
      Citation: Journal of Composites Science
      PubDate: 2022-01-07
      DOI: 10.3390/jcs6010021
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 22: Thermal Behavior of a Light
           Timber-Frame Wall vs. a Theoretical Simulation with Various Insulation
           Materials

    • Authors: Konstantinos Ninikas, Porfyrios Tallaros, Andromachi Mitani, Dimitrios Koutsianitis, Georgios Ntalos, Hamid R. Taghiyari, Antonios N. Papadopoulos
      First page: 22
      Abstract: The objective of this paper is to compare the thermal behavior of a light frame timber wall by measuring 15 test samples with various insulation materials versus a theoretical simulation with the use of a software. This work establishes the variance between the two different methods to measure the thermal transmittance coefficient of timber walls. It is verified that the mean percentage alteration between the two methods is 4.25%. Furthermore, this approach proved that with the use of a simulation software, additional readings (humidity, vapor flux, heat flux, and vapor pressure) can also be considered and measured, enhancing the overall development of a timber wall. This can provide additional information regarding to the characteristics of the masonry’s elements assisting in an improved design of a timber wall with upgraded performance.
      Citation: Journal of Composites Science
      PubDate: 2022-01-08
      DOI: 10.3390/jcs6010022
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 23: A Review on the Performance Evaluation
           of Autonomous Self-Healing Bacterial Concrete: Mechanisms, Strength,
           Durability, and Microstructural Properties

    • Authors: Salmabanu Luhar, Ismail Luhar, Faiz Uddin Ahmed Shaikh
      First page: 23
      Abstract: The development of cracks, owing to a relatively lower tensile strength of concrete, diverse loading, and environmental factors driving the deterioration of structures, is an inescapable key concern for engineers. Reparation and maintenance operations are thus extremely important to prevent cracks from spreading and mitigating the lifetime of structures. However, ease of access to the cracked zone may be challenging, and it also needs funds and manual power. Hence, autonomous sealing of cracks employing microorganisms into the concrete sans manual intervention is a promising solution to the dilemma of the sustainable improvement of concrete. ‘Ureolytic bacteria’, key organism species in rumen-producing ‘urease’ enzymes such as Bacillus pasteurii or subtilis—when induced—are capable of producing calcium carbonate precipitations into the concrete. As their cell wall is anionic, CaCO3 accumulation on their surface is extensive, and the whole cell, therefore, becomes crystalline and ultimately plugs pores and cracks. This natural induction technique is an environmentally friendly method that researchers are studying intensively. This manuscript reviews the application process of bacterial healing to manufacture autonomous self-healing bacterial concrete. Additionally, it provides a brief review of diverse attributes of this novel concrete which demonstrate the variations with the auto-addition of different bacteria, along with an evaluation of crack healing as a result of the addition of these bacteria directly into concrete or after encapsulation in a protective shell. Comparative assessment techniques for autonomous, bio-based self-healing are also discussed, accompanied by progress, potential, modes of application of this technique, and its resultant benefits in the context of strength and durability. Imperatives for quantitative sustainability assessment and industrial adoption are identified, along with the sealing of artificially cracked cement mortar with sand as a filling material in given spaces, as well as urea and CaCl2 medium treatment with Bacillus pasteurii and Sporosarcina bacteria. The assessment of the impact on the compressive strength and rigidity of cement mortar cubes after the addition of bacteria into the mix is also considered. Scanning electron microscope (SEM) images on the function of bacteria in mineral precipitation that is microbiologically induced are also reviewed. Lastly, future research scope and present gaps are recognised and discussed.
      Citation: Journal of Composites Science
      PubDate: 2022-01-11
      DOI: 10.3390/jcs6010023
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 24: Thermal Qualification of the UHTCMCs
           Produced Using RF-CVI Technique with VMK Facility at DLR

    • Authors: Vinothini Venkatachalam, Sergej Blem, Ali Gülhan, Jon Binner
      First page: 24
      Abstract: Ultra high-temperature ceramic matrix composites (UHTCMCs) based on carbon fibre (Cf) have been shown to offer excellent temperature stability exceeding 2000 °C in highly corrosive environments, which are prime requirements for various aerospace applications. In C3Harme, a recent European Union-funded Horizon 2020 project, an experimental campaign has been carried out to assess and screen a range of UHTCMC materials for near-zero ablation rocket nozzle and thermal protection systems. Samples with ZrB2-impregnated pyrolytic carbon matrices and 2.5D woven continuous carbon fibre preforms, produced by slurry impregnation and radio frequency aided chemical vapour infiltration (RF-CVI), were tested using the vertical free jet facility at DLR, Cologne using solid propellants. When compared to standard CVI, RFCVI accelerates pyrolytic carbon densification, resulting in a much shorter manufacturing time. The samples survived the initial thermal shock and subsequent surface temperatures of >2000 °C with a minimal ablation rate. Post-test characterisation revealed a correlation between surface temperature and an accelerated catalytic activity, which lead to an understanding of the crucial role of preserving the bulk of the sample.
      Citation: Journal of Composites Science
      PubDate: 2022-01-11
      DOI: 10.3390/jcs6010024
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 25: Thermoelectric Performance of
           Polypropylene/Carbon Nanotube/Ionic Liquid Composites and Its Dependence
           on Electron Beam Irradiation

    • Authors: Oliver Voigt, Beate Krause, Petra Pötschke, Michael T. Müller, Sven Wießner
      First page: 25
      Abstract: The thermoelectric behavior of polypropylene (PP) based nanocomposites containing single walled carbon nanotubes (SWCNTs) and five kinds of ionic liquids (Ils) dependent on composite composition and electron beam irradiation (EB) was studied. Therefore, several samples were melt-mixed in a micro compounder, while five Ils with sufficiently different anions and/or cations were incorporated into the PP/SWCNT composites followed by an EB treatment for selected composites. Extensive investigations were carried out considering the electrical, thermal, mechanical, rheological, morphological and, most significantly, thermoelectric properties. It was found that it is possible to prepare n-type melt-mixed polymer composites from p-type commercial SWCNTs with relatively high Seebeck coefficients when adding four of the selected Ils. The highest Seebeck coefficients achieved in this study were +49.3 µV/K (PP/2 wt.% SWCNT) for p-type composites and −27.6 µV/K (PP/2 wt.% SWCNT/4 wt.% IL type AMIM Cl) for n-type composites. Generally, the type of IL is decisive whether p- or n-type thermoelectric behavior is achieved. After IL addition higher volume conductivity could be reached. Electron beam treatment of PP/SWCNT leads to increased values of the Seebeck coefficient, whereas the EB treated sample with IL (AMIM Cl) shows a less negative Seebeck coefficient value.
      Citation: Journal of Composites Science
      PubDate: 2022-01-11
      DOI: 10.3390/jcs6010025
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 26: Role of Solvent Polarity on Dispersion
           Quality and Stability of Functionalized Carbon Nanotubes

    • Authors: Dhivakar Rajendran, Rajarajan Ramalingame, Anurag Adiraju, Hanen Nouri, Olfa Kanoun
      First page: 26
      Abstract: Dispersion of carbon nanotubes (CNT) in solvents and/or polymers is essential to reach the full potential of the CNTs in nanocomposite materials. Dispersion of CNTs is especially challenging due to the van-der-Waals attraction forces between the CNTs, which let them tend to re-bundle and/or re-aggregate. This paper presents a brief analysis of the quality and stability of functionalized multiwalled carbon nanotubes (fMWCNT) dispersion on polar solvents. A comparative study of functionalized CNT dispersion in water, methyl, and alcohol-based organic solvents has been carried out and the dispersion has been characterized by UV-VIS spectroscopy, electrochemical characterization such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Visual analysis of the dispersion has been investigated for up to 14 days to assess the dispersion’s stability. Based on the material characterization, it was observed that the degree of affinity fMWCNT with -COOH group highly depends on the polarity of the solvent, where the higher the polarity, the better the interaction of fMWCNT with solvents.
      Citation: Journal of Composites Science
      PubDate: 2022-01-11
      DOI: 10.3390/jcs6010026
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 27: Thermoplastic Composites: Modelling
           Melting, Decomposition and Combustion of Matrix Polymers

    • Authors: Mamadou Ndiaye, Peter Myler, Baljinder K. Kandola
      First page: 27
      Abstract: In thermoplastic composites, the polymeric matrix upon exposure to heat may melt, decompose and deform prior to burning, as opposed to the char-forming matrices of thermoset composites, which retain their shape until reaching a temperature at which decomposition and ignition occur. In this work, a theoretical and numerical heat transfer model to simulate temperature variations during the melting, decomposition and early stages of burning of commonly used thermoplastic matrices is proposed. The scenario includes exposing polymeric slabs to one-sided radiant heat in a cone calorimeter with heat fluxes ranging from 15 to 35 kW/m2. A one-dimensional finite difference method based on the Stefan approach involving phase-changing and moving boundary conditions was developed by considering convective and radiative heat transfer at the exposed side of the polymer samples. The polymers chosen to experimentally validate the simulated results included polypropylene (PP), polyester (PET), and polyamide 6 (PA6). The predicted results match well with the experimental results.
      Citation: Journal of Composites Science
      PubDate: 2022-01-12
      DOI: 10.3390/jcs6010027
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 28: Preparation of a Photosensitive
           Composite Carbon Fiber for Spilled Oil Cleaning

    • Authors: Yong X. Gan, Ali Arjan, Jimmy Yik
      First page: 28
      Abstract: This paper deals with preparing a functional composite carbon fiber with a large surface area for spilled oil cleaning. The composite fiber consisted of photosensitive oxide particles and polymer-derived carbon. It was made by co-spinning the polymer and metallic compounds. After heat treatment at high temperatures, an activated carbon fiber containing oxide particles was obtained. The particles were found distributed in the fiber and at the surface of the fiber. The composite fiber was found sensitive to sunlight. Fiber mats made of the composite fiber possessed a high surface area for oil absorption and removal. Cobalt(II) titanate particles were obtained from the reaction of titanium dioxide and cobalt oxide. The reaction happened in situ through the hydrolysis of metallic compounds in the spun fiber. The titanium dioxide and cobalt(II) titanate particle-containing fibers demonstrated the photoactivity in the visible light spectrum. It was concluded that particle-containing composite carbon fiber mats can be prepared successfully by co-electrospinning. Due to the oleophilic property and the high active surface area, the composites are suitable for spilled oil cleaning through fast absorption.
      Citation: Journal of Composites Science
      PubDate: 2022-01-12
      DOI: 10.3390/jcs6010028
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 29: Cure Kinetics of Samarium-Doped
           Fe3O4/Epoxy Nanocomposites

    • Authors: Maryam Jouyandeh, Mohammad Reza Ganjali, Mehdi Mehrpooya, Otman Abida, Karam Jabbour, Navid Rabiee, Sajjad Habibzadeh, Amin Hamed Mashahdzadeh, Alberto García-Peñas, Florian J. Stadler, Mohammad Reza Saeb
      First page: 29
      Abstract: To answer the question “How does lanthanide doping in iron oxide affect cure kinetics of epoxy-based nanocomposites'”, we synthesized samarium (Sm)-doped Fe3O4 nanoparticles electrochemically and characterized it using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-Ray analysis (EDX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy analyses (XPS). The magnetic particles were uniformly dispersed in epoxy resin to increase the curability of the epoxy/amine system. The effect of the lanthanide dopant on the curing reaction of epoxy with amine was explored by analyzing differential scanning calorimetry (DSC) experimental data based on a model-free methodology. It was found that Sm3+ in the structure of Fe3O4 crystal participates in cross-linking epoxy by catalyzing the reaction between epoxide rings and amine groups of curing agents. In addition, the etherification reaction of active OH groups on the surface of nanoparticles reacts with epoxy rings, which prolong the reaction time at the late stage of reaction where diffusion is the dominant mechanism.
      Citation: Journal of Composites Science
      PubDate: 2022-01-17
      DOI: 10.3390/jcs6010029
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 30: Valorisation of Waste Glasses for the
           Development of Geopolymer Mortar—Properties and Applications: An
           Appraisal

    • Authors: Salmabanu Luhar, Ismail Luhar
      First page: 30
      Abstract: The current review paper studies the most noteworthy points in the fabrication of inorganic, eco-benign geopolymer mortar stressing the valorisation of Waste of Glasses (WG) about its properties and applications. Only a few studies are so far accessible on the topic, and therefore, more advanced studies in this respect will be valuable to construction industries and the research scientist, too. Mostly, the centre of attention on its valorisation with WG points a finger to its attitude to embrace the “conversion of wastes into best” strategy. Up until now, their character is neither well understood nor as embraced as OPC mortars. That is why this article reviews its confined literature with an aim to comprehend the valorisation of WG incorporation with geopolymer mortar, and it also reviews studies on its properties and applications, establishing it as a forthcoming constructive, productive, cost-effective, and sustainable large-scale construction material. The recommendations of this paper will be helpful for potential researchers on the topic. However, there are some challenges, such as curing impediments, occasionally practical antagonises of use, a restrained chain of supply, and a precondition for a sharp-eyed command of mixing design for preparing it for use in roadways to replace OPC counterparts in industry. When fabricated by employing abundantly available precursors, activators, and WG up to the standard superior control of varied properties, chiefly strength, durability, and the low-carbon footprints of alkali activators, GP mortars supplemented with WG are ground-breaking approaches to part of the prospect toolbox of sustainable and reasonably inexpensive construction materials. Finally, the paper identifies research work challenges, endorsement of utilisation, and most essentially the features of its properties and pertinent discussions for this promising new kind of valorised construction material.
      Citation: Journal of Composites Science
      PubDate: 2022-01-17
      DOI: 10.3390/jcs6010030
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 31: Modeling Fracture Formation, Behavior
           and Mechanics of Polymeric Materials: A Biomedical Implant Perspective

    • Authors: Quazi Md. Zobaer Shah, Md. Arefin Kowser, Mohammad Asaduzzaman Chowdhury, Muhammad Tariq Saeed Chani, Khalid A. Alamry, Nayem Hossain, Mohammed M. Rahman
      First page: 31
      Abstract: In industrial applications where contact behavior of materials is characterized, fretting-associated fatigue plays a vital role as a failure agitator. While considering connection, it encounters friction. Biomaterials like polytetrafluoroethylene (PTFE) and ultra-high-molecular-weight polyethylene (UHMWPE) are renowned for their low coefficient of friction and are utilized in sophisticated functions like the hip joint cup and other biomedical implants. In addition to the axial stresses, some degree of dynamic bending stress is also developed occasionally in those fretting contacts. This research investigated the fracture behavior of a polymer PTFE under bending fretting fatigue. Finite element analysis justified the experimental results. A mathematical model is proposed by developing an empirical equation for fracture characterization in polymers like PTFE. It was found that the bending stiffness exists below the loading point ratio (LPR) 3.0, near the collar section of the specimen. Along with fretting, the bending load forces the specimen to crack in a brittle-ductile mode near the sharp-edged collar where the maximum strain rate, as well as stress, builds up. For a loading point ratio of above 3, a fracture takes place near the fretting pads in a tensile-brittle mode. Strain proportionality factor, k was found as a life optimization parameter under conditional loading. The microscopic analysis revealed that the fracture striation initiates perpendicularly to the fretting load. The fretting fatigue damage characteristic of PTFE may have a new era for the biomedical application of polymer-based composite materials.
      Citation: Journal of Composites Science
      PubDate: 2022-01-17
      DOI: 10.3390/jcs6010031
      Issue No: Vol. 6, No. 1 (2022)
       
  • J. Compos. Sci., Vol. 6, Pages 1: In Situ Consolidation of Thermoplastic
           Prepreg by Generating Harmonic Oscillations on the Consolidation Roller

    • Authors: Mohammad Bahar, Marco Brysch, Michael Sinapius
      First page: 1
      Abstract: Automation technologies such as Automated Fiber Placement (AFP) or Automated Tape Laying (ATL) are widely used in the aerospace industry today. However, these processes can still be further improved for higher productivity. Fiber-reinforced plastics allow the production of components with extremely high specific strength and stiffness. Regarding the automated manufacturing processes, the thermoplastic tape placement offers efficiency improvements compared to the nowadays more commonly used thermoset tape placement, especially through the substitution of the expensive and time-consuming autoclave process. The consolidation of thermoplastic Prepregs is achieved with an elastic or rigid roller according to the current state of the art. The Prepregs must be consolidated precisely on the substrate or on top of each other. The most important process parameters for high-quality laminate structure with low porosity are the control of heat source, consolidation force, consolidation roll speed, and tape tension. The efficiency of the AFP process can generally be improved by increasing the speed of the consolidation roller. By increasing the speed of the consolidation roller, porosity is increased and mechanical properties of the laminate are reduced significantly due to the short contact time between consolidation roller and Prepregs. This study investigates a process that can reduce these challenges by increasing the contact time and force duration of the consolidation roller on the Prepregs. The consolidation roller in this study is additionally to be driven by the harmonic oscillations. The new method allows the consolidation roller to oscillate forward and backward during the fiber placement process. This creates another force vector in addition to the compressive force of the consolidation roller and increases the bonding strength between the layers.
      Citation: Journal of Composites Science
      PubDate: 2021-12-21
      DOI: 10.3390/jcs6010001
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 2: Fatigue Behavior of Smart Composites
           with Distributed Fiber Optic Sensors for Offshore Applications

    • Authors: Monssef Drissi-Habti, Venkadesh Raman
      First page: 2
      Abstract: Continuous inspection of critical zones is essential to monitor the state of strain within offshore wind blades, thus, enabling appropriate actions to be taken when needed to avoid heavy maintenance. Wind-turbine blades contain various substructures made of composites, sandwich panel, and bond-joined parts that need reliable Structural Health Monitoring (SHM) techniques. Embedded, distributed Fiber-Optic Sensors (FOS) are one of the most promising techniques that are commonly used for large-scale smart composite structures. They are chosen as monitoring systems for their small size, being noise-free, and low electrical risk characteristics. In recent works, we have shown that embedded FOSs can be positioned linearly and/or in whatever position with the scope of providing pieces of information about actual strain in specific locations. However, linear positioning of distributed FOS fails to provide all strain parameters, whereas sinusoidal sensor positioning has been shown to overcome this issue. This method can provide multiparameter strains over the whole area when the sensor is embedded. Nevertheless, and beyond what a sensor can offer as valuable information, the fact remains that it is a “flaw” from the perspective of mechanics and materials. In this article and through some mechanical tests on smart composites, evidence was given that the presence of embedded FOS influences the mechanical behavior of smart composites, whether for quasi-static or fatigue tests, under 3-point bending. Some issues directly related to the fiber-architecture have to be solved.
      Citation: Journal of Composites Science
      PubDate: 2021-12-22
      DOI: 10.3390/jcs6010002
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 3: Implementation on a Preparation and
           Controlled Compaction Procedure for Waste-Fiber-Reinforced Raw Earth
           Samples

    • Authors: Mazhar Hussain, Daniel Levacher, Léo Saouti, Nathalie Leblanc, Hafida Zmamou, Irini Djeran-Maigre, Andry Razakamanantsoa
      First page: 3
      Abstract: Earth bricks are a traditional eco-friendly construction material. In this study, harbor-dredged sediments were used along with hemp shiv to develop a brick manufacturing procedure and compaction techniques to produce durable earth bricks for the valorization of waste hemp shiv and dredged sediments. Prismatic specimens of size 4 × 4 × 16 cm3 were manufactured with Dunkirk sediments after analyzing their suitability for earth bricks according to the French standard for flexural strength test to observe the indirect tensile strength and impact of the compaction techniques on the strength of bricks. Crude bricks were manufactured with varying hemp shiv content from 0% to 5% by mass. Compaction techniques such as dynamic compaction, static compaction, and tamping were applied. The effect of hemp shiv content and compaction techniques was evaluated with a flexural strength test and the distribution of fibers in bricks. Grain size analysis of sediments with French and Spanish standards shows that the sediments granulometry is suitable for earth bricks. The flexural strength testing of bricks indicates that bricks with saturated hemp shiv have higher flexural strength. Earth bricks have maximum strength with dynamic compaction with 1% hemp shiv, which satisfies the adobe bricks tensile strength requirements that vary from 0.012 to 0.025 MPa (NZS 4298, 1998; NORMA E.080 (2017).
      Citation: Journal of Composites Science
      PubDate: 2021-12-23
      DOI: 10.3390/jcs6010003
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 4: Platinum-Decorated TiO2: One Step Fast
           Monometallic Impregnation and Plasma Effect on Nanoparticles

    • Authors: Rudy Trejo-Tzab, Alejandro Avila-Ortega, Patricia Quintana-Owen, Ricardo Rangel, Mayra Angélica Álvarez-Lemus
      First page: 4
      Abstract: In the present work, N-TiO2−x/Pt was synthesized using a homemade nitrogen plasma (AC) discharge system. The overall procedure use of low-power nitrogen plasma (100 watts) with 1 and 2 h of plasma discharge to successfully impregnate platinum nanoparticles on P25 titanium dioxide. The obtained samples were characterized using X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM). The results reveal the incorporation of metallic Pt up to 2.9% on the surface of TiO2 by increasing the duration of plasma discharge by up to two hours with a constant power of 100 watts. Likewise, the incorporation of nitrogen atoms into a lattice crystal was also favored, confirming a direct relationship between the amount of Pt and nitrogen atoms introduced in TiO2 as a function of the duration of plasma treatment. By characterizing nanoparticles loaded on a N-TiO2−x/Pt surface, we show that joined platinum nanoparticles have two different patterns, and the boundary between these two regions coalesces. The results demonstrate that the use of nitrogen plasma to impregnate platinum nanoparticles on the surface of TiO2 to obtain N-TiO2−x/Pt allows wide and relevant physics and chemistry applications.
      Citation: Journal of Composites Science
      PubDate: 2021-12-24
      DOI: 10.3390/jcs6010004
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 5: Effectiveness of Sodium Acetate
           Treatment on the Mechanical Properties and Morphology of Natural
           Fiber-Reinforced Composites

    • Authors: Dionisio Badagliacco, Vincenzo Fiore, Carmelo Sanfilippo, Antonino Valenza
      First page: 5
      Abstract: This paper aims to investigate the ability of an eco-friendly and cheap treatment based on sodium acetate solutions to improve the mechanical properties of flax fiber-reinforced composites. Flax fibers were treated for 5 days (i.e., 120 h) at 25 °C with mildly alkaline solutions at 5%, 10% and 20% weight content of the sodium salt. Quasi-static tensile and flexural tests, Charpy impact tests and dynamical mechanical thermal (DMTA) tests were carried out to evaluate the mechanical properties of the resulting composites. Fourier transform infrared analysis (FTIR) was used to evaluate the chemical modification on the fibers surface due to the proposed treatment, whereas scanning electron microscope (SEM) and helium pycnometry were used to get useful information about the morphology of composites. It was found that the treatment with 5% solution of sodium acetate leads to the best mechanical performance and morphology of flax fiber-reinforced composites. SEM analysis confirmed these findings highlighting that composites reinforced with flax fibers treated in 5% sodium acetate solution show an improved morphology compared to the untreated ones. On the contrary, detrimental effects on the morphology as well as on the mechanical performance of composites were achieved by increasing the salt concentration of the treating solution.
      Citation: Journal of Composites Science
      PubDate: 2021-12-25
      DOI: 10.3390/jcs6010005
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 6: Novel Reactive Flex Configuration in
           Kiwi Wing Foil Surfboard

    • Authors: Adrien M. Fat Cheung, Klaudio Bari
      First page: 6
      Abstract: The creation of an ideal surfboard is art. The design and construction depend on the individual surfer’s skill level and type of the required performance. In this research, four fuselage concepts were carefully explored to meet the following unique needs: lightweight, strong, and a fast-manufacturing process. The fuselages were manufactured by compression moulding using skin and core materials. The skin material was selected to be unidirectional (UD) carbon fibre, discontinuous carbon fibre (SMC) and Filava quadriaxial fibre impregnated with epoxy, while the core material was selected to be lightweight PVC foam. To assess the mechanical performance, three-point bending has been performed according to BS-ISO 14125 and validated using Finite Element Analysis (FEA) using Ansys software. As expected, the flexural test revealed that the UD carbon fibre fuselage was the strongest and SMC was the weakest, while large deflection was seen in Filava fibre fuselages before failure, showing great reactive flex that promotes projection during surfing. The experimental results show good agreement with FEA simulation, and the locations of the physical failure in the fuselage matches the location of maximum flexural stress obtained from FEA simulation. Although all fuselages were found to carry a surfer weight of 150 kg, including a factor of safety 3, except the SMC fuselage, due to shrinkage. The Filava fibre fuselages were seen to have a large deflection before failure, showing great flexibility to handle high ocean waves. This promotes the potential use of reactive flex in high performance sports equipment, such as surfing boards. A large shrinkage must be taken under consideration during compression moulding that depends on fibre orientation, resin nature, and part geometry.
      Citation: Journal of Composites Science
      PubDate: 2021-12-26
      DOI: 10.3390/jcs6010006
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 7: State-of-the-Art Review on Additive
           Manufacturing Technology in Railway Infrastructure Systems

    • Authors: Hao Fu, Sakdirat Kaewunruen
      First page: 7
      Abstract: Additive manufacturing technologies, well known as three-dimensional printing (3DP) technologies, have been applied in many industrial fields, including aerospace, automobiles, shipbuilding, civil engineering and nuclear power. However, despite the high material utilization and the ability to rapidly construct complex shaped structures of 3D printing technologies, the application of additive manufacturing technologies in railway track infrastructure is still at the exploratory stage. This paper reviews the state-of-the-art research of additive manufacturing technologies related the railway track infrastructure and discusses the challenges and prospects of 3D printing technology in this area. The insights will not only help the development of 3D printing technologies into railway engineering but also enable smarter railway track component design and improve track performance and inspection strategies.
      Citation: Journal of Composites Science
      PubDate: 2021-12-27
      DOI: 10.3390/jcs6010007
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 8: Anti-Gnawing, Thermo-Mechanical and
           Rheological Properties of Polyvinyl Chloride: Effect of Capsicum Oleoresin
           and Denatonium Benzoate

    • Authors: Laongdaw Techawinyutham, Arnuparb Prasarnsri, Suchart Siengchin, Rapeephun Dangtungee, Sanjay Mavinkere Rangappa
      First page: 8
      Abstract: Anti-rodent polymer composites were prepared using non-toxic substances denatonium benzoate (DB) and capsicum oleroresin (CO) mixed with polyvinyl chloride (PVC) matrix. DB is mixed in zinc stearate (ZnSt) called DB/ZnSt, and CO, providing burning sensation, is impregnated in mesoporous silica named SiCO. There are three sets of sample: Blank, composites Set I and Set II. Set I consists of DB/ZnSt at concentration of 1.96 wt% and SiCO at concentration of 12.16 wt%, 14.47 wt%, 18.75 wt% and 23.53 wt%. Set II comprises SiCO at the same amount of Set I. The anti-rodent composites studied are anti-gnawing, surface morphology, thermo-mechanical and rheological properties. Anti-rodent testing is analyzed by one-way blocked analysis of variance (ANOVA) and compared with Tukey test with a 95% level of significance, presenting good anti-gnawing efficiency. The best rat-proof sample is II.4, consisting of SiCO 23.53 wt%, which presents percentage of weight loss from gnawing at 1.68% compared to weight loss of neat PVC at 59.74%. The addition of SiCO at concentration ranging from 12.16 to 23.53 wt% reduces tensile strength around 25–50%, elongation at break strength around 2–23%, shear storage modulus (G′) around 30%, shear loss modulus (G″) shear viscosity (η) and glass transition (Tg) around 43% compared to Blank. The increase in SiCO concentration slightly improves the thermal stability of PVC composites around 3%, but the addition of DB/ZnSt at 1.96 wt% slightly reduces those properties.
      Citation: Journal of Composites Science
      PubDate: 2021-12-27
      DOI: 10.3390/jcs6010008
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 9: Preparation of ZrO2/Graphene Oxide/TiO2
           Composite Photocatalyst and Its Studies on Decomposition of Organic Matter
           

    • Authors: Yu-Hsun Nien, Jhih-Fong Chen, Cai-Yin Fang, Ming-Sheng Liu
      First page: 9
      Abstract: Water polluted by organic dyes is a serious environmental problem. In response to this, the aim of this research is to degrade dye wastewater using a modified photocatalyst. Since sunlight only has less than 5% UV energy, for a general photocatalyst, using sunlight for excitation to decompose organic pollutants is not an effective way. Therefore, we manufactured the modified photocatalyst by zirconium dioxide, graphene oxide, and titanium dioxide. This was to better improve the photo-degradation efficiency for the degradation of organic pollutants. The modified photocatalyst was analyzed by X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), Scanning Electron Microscope (SEM), and Energy-dispersive X-ray spectroscopy (EDS). The results demonstrated that the modified photocatalyst can be activated by the absorption of visible light. Additionally, the band gap of the modified photocatalyst would decrease. The photodegradation percentage of the modified photocatalyst under visible light (Philips TL-D 8W/865 fluorescent tube) for 4 h reached up to 49.92%. At the third test after ultrasonic washing for the cyclic test, the photodegradation percentage of the modified photocatalyst could still maintain at 47.71%. This indicates that the modified photocatalyst has good stability and reusability, and so this can be reused in this regard.
      Citation: Journal of Composites Science
      PubDate: 2021-12-29
      DOI: 10.3390/jcs6010009
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 10: Modeling Stiffness Degradation of
           Fiber-Reinforced Polymers Based on Crack Densities Observed in Off-Axis
           Plies

    • Authors: Matthias Drvoderic, Martin Pletz, Clara Schuecker
      First page: 10
      Abstract: A model that predicts the stiffness degradation in multidirectional reinforced laminates due to off-axis matrix cracks is proposed and evaluated using data from fatigue experiments. Off-axis cracks are detected in images from the fatigue tests with automated crack detection to compute the crack density of the off-axis cracks which is used as the damage parameter for the degradation model. The purpose of this study is to test the effect of off-axis cracks on laminate stiffness for different laminate configurations. The hypothesis is that off-axis cracks have the same effect on the stiffness of a ply regardless of the acting stress components as long as the transverse stress is positive. This hypothesis proves to be wrong. The model is able to predict the stiffness degradation well for laminates with a ply orientation similar to the one used for calibration but deviates for plies with different in-plane shear stress. This behavior can be explained by the theory that off-axis cracks develop by two different micro damage modes depending on the level of in-plane shear stress. It is found that besides influencing the initiation and growth of off-axis cracks, the stiffness degradation is also mode dependent.
      Citation: Journal of Composites Science
      PubDate: 2021-12-29
      DOI: 10.3390/jcs6010010
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 11: Finite Element Modelling Approach for
           Progressive Crushing of Composite Tubular Absorbers in LS-DYNA: Review and
           Findings

    • Authors: Ali Rabiee, Hessam Ghasemnejad
      First page: 11
      Abstract: Robust finite element models are utilised for their ability to predict simple to complex mechanical behaviour under certain conditions at a very low cost compared to experimental studies, as this reduces the need for physical prototypes while allowing for the optimisation of components. In this paper, various parameters in finite element techniques were reviewed to simulate the crushing behaviour of glass/epoxy tubes with different material models, mesh sizes, failure trigger mechanisms, element formulation, contact definitions, single and various numbers of shells and delamination modelling. Six different modelling approaches, namely, a single-layer approach and a multi-layer approach, were employed with 2, 3, 4, 6, and 12 shells. In experimental studies, 12 plies were used to fabricate a 3 mm wall thickness GFRP specimen, and the numerical results were compared with experimental data. This was achieved by carefully calibrating the values of certain parameters used in defining the above parameters to predict the behaviour and energy absorption response of the finite element model against initial failure peak load (stiffness) and the mean crushing force. In each case, the results were compared with each other, including experimental and computational costs. The decision was made from an engineering point of view, which means compromising accuracy for computational efficiency. The aim is to develop an FEM that can predict energy absorption capability with a higher level of accuracy, around 5% error, than the experimental studies.
      Citation: Journal of Composites Science
      PubDate: 2021-12-29
      DOI: 10.3390/jcs6010011
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 12: Impacts of Lithium Salts on the Thermal
           and Mechanical Characteristics in the Lithiated PEO/LAGP Composite
           Electrolytes

    • Authors: Jeremy Lee, Michael Rottmayer, Hong Huang
      First page: 12
      Abstract: Lithium batteries utilizing solid-state electrolytes have the potential to alleviate their safety hazard, reduce packaging volume, and enable flexible design. Polymer/ceramic composite electrolytes (CPE) are more attractive because the combination is capable of remedying and/or transcending individual constituent’ properties. Recently, we fabricated a series of free-standing composite electrolyte membranes consisting of Li1.4Al0.4Ge1.6(PO4)3 (LAGP), polyethylene oxide (PEO), and lithium salts. In this study, we characterized thermal and mechanical properties of the CPEs with two representative lithium salts, i.e., lithium boron fluoride (LiBF4) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). We found that the type of lithium salt can prevail the LAGP ceramic loadings on altering the key properties. It is observed that LiTFSI, compared with LiBF4, causes more significant reduction in terms of the crystallinity of PEO, melting transition, and mechanical strengths. The differences in these aspects can be ascribed to the interactions between the polymer matrix and anions in lithium salt.
      Citation: Journal of Composites Science
      PubDate: 2021-12-30
      DOI: 10.3390/jcs6010012
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 13: Damping Properties of Hybrid Composites
           Made from Carbon, Vectran, Aramid and Cellulose Fibers

    • Authors: Hauke Kröger, Stephan Mock, Christoph Greb, Thomas Gries
      First page: 13
      Abstract: Hybridization of carbon fiber composites can increase the material damping of composite parts. However, there is little research on a direct comparison of different fiber materials—particularly for carbon fiber intraply-hybrid composites. Hence, the mechanical- and damping properties of different carbon fiber intraply hybrids are analyzed in this paper. Quasi unidirectional fabrics made of carbon, aramid, Vectran and cellulose fibers are produced, and their mechanical properties are analyzed. The material tests show an increased material damping due to the use of Vectran and aramid fibers, with a simultaneous reduction in strength and stiffness.
      Citation: Journal of Composites Science
      PubDate: 2021-12-31
      DOI: 10.3390/jcs6010013
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 6, Pages 14: Investigation of Fatigue Behavior of
           Three Dimensional Interlock Composites by Time-Lapse Micro-Computed
           Tomography

    • Authors: Christophe Cruanes, Keerthi Krishna Parvathaneni, Dmytro Vasiukov, Chung Hae Park
      First page: 14
      Abstract: The mechanism of the crack propagation in three dimensional (3D) glass-fiber warp interlock epoxy composites under fatigue loading was investigated via time-lapse micro-computed tomography (µCT) observations. Two different composite samples were manufactured by means of a resin transfer molding (RTM) process under two different constant injection pressure conditions to generate intrayarn and interyarn voids separately. Fatigue loads were applied by blocks of 105 cycles and followed by µCT measurements. Regions of interest for micro tomography scans were selected based on hot spots detected by infrared thermography. After the analysis of the obtained data, it was observed that detectable cracks were generally initiated by debonding in the zone between two adjacent warp yarns and grew along their interface. Then, these cracks propagated along one of the warp yarns aligned in the loading direction while remaining in the middle of the specimen cross-section. The coalescence of the cracks and further propagation to the weakest zones were observed around and after the middle lifetime. Finally, we demonstrated the influence of the void defects at different material scales. I was found that interyarn voids have relatively little influence on the fatigue performance whereas they can, sometimes, attract and deviate cracks in the matrix zone between adjacent yarns. It was also shown that the intrayarn voids are crucial to degenerate the fatigue performance of the yarns at the micro-scale.
      Citation: Journal of Composites Science
      PubDate: 2021-12-31
      DOI: 10.3390/jcs6010014
      Issue No: Vol. 6, No. 1 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 307: Manufacturing and Performance of
           Carbon Short Fiber Reinforced Composite Using Various Aluminum Matrix

    • Authors: Yongbum Choi, Xuan Meng, Zhefeng Xu
      First page: 307
      Abstract: A new fabrication process without preform manufacturing has been developed for carbon short fiber (CSF) reinforced various aluminum matrix composites. And their mechanical and thermal properties were evaluated. Electroless Ni plating was conducted on the CSF for improving wettability between the carbon fiber (CF) and aluminum. It was confirmed that pores in Ni plated CSF/Al and Al alloy matrix composites prepared by applied pressure, 0.8 MPa, had some imperfect infiltration regions between the CF/CF and CF/matrix in all composites. However, pores size in the region between the CF/CF and CF/matrix to use the A336 matrix was about 1 µm. This size is smaller than that of other aluminum-based composites. Vickers hardness of Ni plated CSF/A1070, A356 alloy, and A336 alloy composites were higher as compared to matrix. However, the A1070 pure aluminum matrix composite had the highest hardness improvement. The Ultimate tensile strength of the A1070 and A356 aluminum matrix composite was increased due to carbon fiber compared to only aluminum, but the Ultimate tensile strength of the A336 aluminum matrix composite was rather lowered due to the highest content of Si precipitate and large size of Al3Ni compounds. The Thermal Conductivity of Ni plated CSF/A1070 composite has the highest value (167.1 W·m−1·K−1) as compared to composites.
      Citation: Journal of Composites Science
      PubDate: 2021-11-24
      DOI: 10.3390/jcs5120307
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 308: Investigations on Structural and
           Optical Properties of Various Modifier Oxides (MO = ZnO, CdO, BaO, and
           PbO) Containing Bismuth Borate Lithium Glasses

    • Authors: J. Bhemarajam, P. Syam Prasad, M. Mohan Babu, Mutlu Özcan, M. Prasad
      First page: 308
      Abstract: Bismuth based quaternary glasses with compositions BiBLM: 50Bi2O3–20B2O3–15Li2O–15MO (where MO = ZnO, CdO, BaO, and PbO) were processed by conventional melt quenching. The effectiveness of various modifier oxides on the optical and structural properties of the developed glasses was studied systematically by XRD, DSC, FTIR, Raman, and optical absorption (OA) measurements. The synthesized glass specimens were characterized by XRD and the patterns demonstrated an amorphous nature. The physical characteristics such as molar mass, density, and OPD values were found to increase with an increase in the molar mass of the modifier oxides, while there was a decrement in oxygen molar volume, thus resulting in decrement of complete molar volume of the prepared glasses. From DSC analysis, incorrigible reduction and enhancement of Tg and thermal stability among various modifier oxides in the glass network was noticed. Optical absorption data for glass specimens have confirmed the decrease in both direct and indirect optical band gap values among various modifier oxides incorporation. These investigations support the obtained Urbach energy (UE) and metallization criteria of synthesized glasses. The ionic characteristic for the glass specimens were confirmed by the values of electronic polarizability and electronegativity. The Raman and FT-IR spectra of the glass specimens displayed the existence of BiO3, BiO6, ZnO4, CdO4, BaO4, BO3, PbO4, and BO4 structural units within the glass matrix. These structural results can support the applications of as-developed glasses in the area of photonics.
      Citation: Journal of Composites Science
      PubDate: 2021-11-25
      DOI: 10.3390/jcs5120308
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 309: Flexible and High Thermal Conductivity
           Composites Based on Graphite Nanoplates Paper Impregnated with
           Polydimethylsiloxane

    • Authors: Daniele Battegazzore, Erica Fadda, Alberto Fina
      First page: 309
      Abstract: This paper deals with the design, preparation, and characterization of conductive and flexible nanopapers based on graphite nanoplates (GNP) and polydimethylsiloxane (PDMS). Highly porous GNP nanopapers were first prepared by filtration from a GNP suspension in a solvent. Subsequently, PDMS impregnation was carried out to obtain a composite material. By varying the concentration of the polymer solution and the deposition time, PDMS/GNP nanopapers were produced with a wide range of PDMS contents, porosities, and densities. Thermal diffusivity of the composite films (both in-plane and cross-plane) were measured and correlated with the structure of the nanopapers. Selected formulations were investigated in detail for their physical, thermal, and mechanical properties, exhibiting high flexibility and resistance to more than 50 repeated bendings, stiffness of up to 1.3 MPa, and thermal conductivity of up to 25 W/m∙K. Based on the properties obtained, the materials presented in this paper may find applications in modern lightweight and flexible electronic devices.
      Citation: Journal of Composites Science
      PubDate: 2021-11-25
      DOI: 10.3390/jcs5120309
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 310: Influence of Failure Criteria and
           Intralaminar Damage Progression Numerical Models on the Prediction of the
           Mechanical Behavior of Composite Laminates

    • Authors: Aniello Riccio, Concetta Palumbo, Valerio Acanfora, Andrea Sellitto, Angela Russo
      First page: 310
      Abstract: This work evaluates the effectiveness of commonly adopted local damage evolution methods and failure criteria in finite element analysis for the simulation of intralaminar damage propagation in composites under static loading conditions. The proposed numerical model is based on a User Defined Material subroutine (USERMAT) implemented in Ansys. This model is used to predict the evolution of damage within each specific lamina of a composite laminate by introducing both sudden and gradual degradation rules. The main purpose of the simulations is to quantitatively assess the influence of the adopted failure criteria in conjunction with degradation laws on the accuracy of the numerical predictions in terms of damage evolution and failure load. The mechanical behavior of an open hole tension specimen and of a notched stiffened composite panel under shear loading conditions have been numerically simulated by Progressive Damage Models (PDM). Different failure criteria have been implemented in the developed Ansys USERMAT, together with sudden and gradual degradation rules based on the Continuum Damage Mechanics (CDM) approach. Numerical results have been validated against experimental data to assess the effects of the different failure criteria and damage evolution law on the global mechanical response and local damage predictions in composite laminates.
      Citation: Journal of Composites Science
      PubDate: 2021-11-26
      DOI: 10.3390/jcs5120310
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 311: Can Empirical Biplots Predict High
           Entropy Oxide Phases'

    • Authors: Zhaoyuan Leong, Pratik Desai, Nicola Morley
      First page: 311
      Abstract: High entropy oxides are entropy-stabilised oxides that adopt specific disordered structures due to entropy stabilisation. They are a new class of materials that utilises the high-entropy concept first discovered in metallic alloys. They can have interesting properties due to the interactions at the electronic level and can be combined with other materials to make composite structures. The design of new meta-materials that utilise this concept to solve real-world problems may be a possibility but further understanding of how their phase stabilisation is required. In this work, biplots of the composition’s mean electronegativity are plotted against the electron-per-atom ratio of the compounds. The test dataset accuracy in the resulting biplots improves from 78% to 100% when using atomic-number-per-atom Z/a ratios as a biplot parameter. Phase stability maps were constructed using a Voronoi tessellation. This can be of use in determining stability at composite material interfaces.
      Citation: Journal of Composites Science
      PubDate: 2021-11-26
      DOI: 10.3390/jcs5120311
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 312: Rubberized Geopolymer Composites:
           Value-Added Applications

    • Authors: Ismail Luhar, Salmabanu Luhar
      First page: 312
      Abstract: The discovery of an innovative class of inorganic polymers has brought forth a revolution in the history of construction technology. Now, no energy-intensive reactions at elevated temperatures are essential, as found in the case of contemporary cement production. In addition to their attributes of low energy and a mitigated carbon footprint, geopolymeric composites can incorporate diversely originated and profound wastes in their manufacturing. As of today, profoundly accessible landfills of rubber tyre waste negatively impact the environment, water, and soil, with many health hazards. Their nonbiodegradable complex chemical structure supports recycling, and toxic gases are emitted by burning them, leading to aesthetic issues. These, altogether, create great concern for well-thought-out disposal methods. One of the achievable solutions is processing this waste into alternative aggregates to thus generate increased economic value whilst reducing primary aggregate consumption through the incorporation of these vast automobile solid wastes in the manufacturing of geopolymer construction composites, e.g., binders, mortar, concrete, etc., produced through the process of geopolymerization as a replacement for natural aggregates, providing relief to the crisis of the degradation of restricted natural aggregate resources. Currently, tyre rubber is one of the most outstanding materials, extensively employed in scores of engineering applications. This manuscript presents a state-of-the-art review of value-added applications in the context of rubberized geopolymer building composites and a review of past investigations. More significantly, this paper reviews rubberized geopolymer composites for their value-added applications.
      Citation: Journal of Composites Science
      PubDate: 2021-11-27
      DOI: 10.3390/jcs5120312
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 313: Mechanical and FEA-Assisted
           Characterization of 3D Printed Continuous Glass Fiber Reinforced Nylon
           Cellular Structures

    • Authors: Evangelos Giarmas, Konstantinos Tsongas, Emmanouil K. Tzimtzimis, Apostolos Korlos, Dimitrios Tzetzis
      First page: 313
      Abstract: The main objective of this study was to investigate the mechanical behavior of 3D printed fiberglass-reinforced nylon honeycomb structures. A Continuous Fiber Fabrication (CFF) 3D printer was used since it makes it possible to lay continuous strands of fibers inside the 3D printed geometries at selected locations across the width in order to optimize the bending behavior. Nylon and nylon/fiberglass honeycomb structures were tested under a three-point bending regime. The microstructure of the filaments and the 3D printed fractured surfaces following bending tests were examined with Scanning Electron Microscopy (SEM). The modulus of the materials was also evaluated using the nanoindentation technique. The behavior of the 3D printed structures was simulated with a Finite Element Model (FEM). The experimental and simulation results demonstrated that 3D printed continuous fiberglass reinforcement is possible to selectively adjust the bending strength of the honeycombs. When glass fibers are located near the top and bottom faces of honeycombs, the bending strength is maximized.
      Citation: Journal of Composites Science
      PubDate: 2021-11-27
      DOI: 10.3390/jcs5120313
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 314: Controllable Synthesis of
           Graphene-Encapsulated NiFe Nanofiber for Oxygen Evolution Reaction
           Application

    • Authors: Mengyang Li, Jiayi Rong, Ning Guo, Susu Chen, Meiqi Gao, Feng Cao, Guoqing Li
      First page: 314
      Abstract: Carbon-Encapsulated NiFe Nanofiber NixFey@C-CNFs have been demonstrated to be promising candidates to replace conventional nobel metals-based catalysts for oxygen evolution reaction. Here, we developed a facile method of electrospinning and high temperature carbonization to synthesize NixFey@C-CNFs catalysts. It is proved that Ni3Fe7@C-CNFs exhibited low overpotential (245 mV) and excellent stability in alkaline electrolyte for OER. This work provides a good platform for the synthesis and design of graphene-encapsulated alloy catalysts.
      Citation: Journal of Composites Science
      PubDate: 2021-11-29
      DOI: 10.3390/jcs5120314
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 315: Strength, Shrinkage and Early Age
           Characteristics of One-Part Alkali-Activated Binders with High-Calcium
           Industrial Wastes, Solid Reagents and Fibers

    • Authors: Dhruv Sood, Khandaker M. A. Hossain
      First page: 315
      Abstract: Alkali-activated binders (AABs) are developed using a dry mixing method under ambient curing incorporating powder-form reagents/activators and industrial waste-based supplementary cementitious materials (SCMs) as precursors. The effects of binary and ternary combinations/proportions of SCMs, two types of powder-form reagents, fundamental chemical ratios (SiO2/Al2O3, Na2O/SiO2, CaO/SiO2, and Na2O/Al2O3), and incorporation of polyvinyl alcohol (PVA) fibers on fresh state and hardened characteristics of 16 AABs were investigated to assess their performance for finding suitable mix compositions. The mix composed of ternary SCM combination (25% fly-ash class C, 35% fly-ash class F, and 40% ground granulated blast furnace slag) with multi-component reagent combination (calcium hydroxide and sodium metasilicate = 1:2.5) was found to be the most optimum binder considering all properties with a 56 day compressive strength of 54 MPa. The addition of 2% v/v PVA fibers to binder compositions did not significantly impact the compressive strengths. However, it facilitated mitigating shrinkage/expansion strains through micro-confinement in both binary and ternary binders. This research bolsters the feasibility of producing ambient cured powder-based cement-free binders and fiber-reinforced, strain-hardening composites incorporating binary/ternary combinations of SCMs with desired fresh and hardened properties.
      Citation: Journal of Composites Science
      PubDate: 2021-11-30
      DOI: 10.3390/jcs5120315
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 316: Injection Molding of Wood-Filled
           Thermoplastic Polyurethane

    • Authors: Elmar Moritzer, Maximilian Richters
      First page: 316
      Abstract: Wood fiber reinforcement of plastics is almost limited to polypropylene, polyethylene, polyvinyl chloride and polystyrene. Wood fiber reinforcement of thermoplastic polyurethanes (TPU) is a new research field and paltry studied scientifically. Wood fiber reinforcement can carry out synergistic effects between sustainability, material or product price reduction, improved mechanical properties at high elongation, and brilliant appearance and haptics. In order to evaluate to what extent the improvement of mechanical properties depend on material-specific parameters (fiber type, fiber content) and on process-specific parameters (holding pressure, temperature control and injection speed), differently filled compounds were injection molded according to a partial factorial test plan and subjected to characterizing test procedures (tensile test, Shore hardness and notched impact test). Tensile strength showed significant dependence on barrel temperature, fiber type and interaction between holding pressure and barrel temperature in the region of interest. Young’s modulus can be influenced by fiber content but not by fiber type. Notched impact strength showed a significant influence of cylinder temperature, fiber content, fiber type and the interaction between cylinder temperature and fiber content in the region of interest. Shore hardness is related to fiber content and the interaction between mold temperature and injection flow rate. Our results show not only that wood-filled TPU can be processed very well by injection molding, but also that the mechanical properties depend significantly on temperature control in the injection-molding process. Moreover, considering the significant reinforcing effect of the wood fibers, a good fiber-matrix adhesion can be assumed.
      Citation: Journal of Composites Science
      PubDate: 2021-11-30
      DOI: 10.3390/jcs5120316
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 317: Solid-State Hydrogen Fuel by
           PSII–Chitin Composite and Application to Biofuel Cell

    • Authors: Yusuke Takahashi, Akinari Iwahashi, Yasumitsu Matsuo, Hinako Kawakami
      First page: 317
      Abstract: Biomaterials attract a lot of attention as next-generation materials. Especially in the energy field, fuel cells based on biomaterials can further develop clean next-generation energy and are focused on with great interest. In this study, solid-state hydrogen fuel (PSII–chitin composite) composed of the photosystem II (PSII) and hydrated chitin composite was successfully created. Moreover, a biofuel cell consisting of the electrolyte of chitin and the hydrogen fuel using the PSII–chitin composite was fabricated, and its characteristic feature was investigated. We found that proton conductivity in the PSII–chitin composite increases by light irradiation. This result indicates that protons generate in the PSII–chitin composite by light irradiation. It was also found that the biofuel cell using the PSII–chitin composite hydrogen fuel and the chitin electrolyte exhibits the maximum power density of 0.19 mW/cm2. In addition, this biofuel cell can drive an LED lamp. These results indicate that the solid-state biofuel cell based on the bioelectrolyte “chitin” and biofuel “the PSII–chitin composite” can be realized. This novel solid-state fuel cell will be helpful to the fabrication of next-generation energy.
      Citation: Journal of Composites Science
      PubDate: 2021-12-01
      DOI: 10.3390/jcs5120317
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 318: The Mechanism of Joint Reduction of
           MoO3 and CuO by Combined Mg/C Reducer at High Heating Rates

    • Authors: Hasmik Kirakosyan, Khachik Nazaretyan, Sofiya Aydinyan, Suren Kharatyan
      First page: 318
      Abstract: Understanding of the decisive role of non-isothermal treatment on the interaction mechanism and kinetics of the MoO3-CuO-Mg-C system is highly relevant for the elaboration of optimal conditions at obtaining Mo-Cu composite powder in the combustion processes. The reduction pathway of copper and molybdenum oxides with combined Mg + C reducing agents at high heating rates from 100 to 5200 K min−1 was delivered. In particular the sequence of the reactions in all the studied binary, ternary and quaternary systems contemporaneously demonstrating the effect of the heating rate on products’ phase composition and microstructure was elucidated. The combination of two highly exothermic and speedy reactions (MoO3 + 3Mg and CuO + Mg vs. MoO3 + CuO + 4Mg) led to a slow interaction with weak self-heating (dysynergistic effect) due to a change in the reaction mechanism. Furthermore, it has been shown that upon the simultaneous utilization of the Mg and C reducing agents, the process initiates exclusively with carbothermic reduction, and at relatively high temperatures it continues with magnesiothermic reaction. The effective activation energy values of the magnesiothermic stages of the studied reactions were determined by Kissinger isoconversional method.
      Citation: Journal of Composites Science
      PubDate: 2021-12-03
      DOI: 10.3390/jcs5120318
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 319: A Review of Sensing Technologies for
           Non-Destructive Evaluation of Structural Composite Materials

    • Authors: Ranjeetkumar Gupta, Daniel Mitchell, Jamie Blanche, Sam Harper, Wenshuo Tang, Ketan Pancholi, Lee Baines, David G. Bucknall, David Flynn
      First page: 319
      Abstract: The growing demand and diversity in the application of industrial composites and the current inability of present non-destructive evaluation (NDE) methods to perform detailed inspection of these composites has motivated this comprehensive review of sensing technologies. NDE has the potential to be a versatile tool for maintaining composite structures deployed in hazardous and inaccessible areas, such as offshore wind farms and nuclear power plants. Therefore, the future composite solutions need to take into consideration the niche requirements of these high-value/critical applications. Composite materials are intrinsically complex due to their anisotropic and non-homogeneous characteristics. This presents a significant challenge for evaluation and the associated data analysis for NDEs. For example, the quality assurance, certification of composite structures, and early detection of the failure is complex due to the variability and tolerances involved in the composite manufacturing. Adapting existing NDE methods to detect and locate the defects at multiple length scales in the complex materials represents a significant challenge, resulting in a delayed and incorrect diagnosis of the structural health. This paper presents a comprehensive review of the NDE techniques, that includes a detailed discussion of their working principles, setup, advantages, limitations, and usage level for the structural composites. A comparison between these techniques is also presented, providing an insight into the future trends for composites’ prognostic and health management (PHM). Current research trends show the emergence of the non-contact-type NDE (including digital image correlation, infrared tomography, as well as disruptive frequency-modulated continuous wave techniques) for structural composites, and the reasons for their choice over the most popular contact-type (ultrasonic, acoustic, and piezoelectric testing) NDE methods is also discussed. The analysis of this new sensing modality for composites’ is presented within the context of the state-of-the-art and projected future requirements.
      Citation: Journal of Composites Science
      PubDate: 2021-12-06
      DOI: 10.3390/jcs5120319
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 320: Outcomes of Ceramic Composite in Total
           Hip Replacement Bearings: A Single-Center Series

    • Authors: Giuseppe Solarino, Antonio Spinarelli, Antonio Virgilio, Filippo Simone, Marco Baglioni, Biagio Moretti
      First page: 320
      Abstract: Despite the fact that total hip replacement is one of the most successful surgical procedures for treatment of a variety of end-stage hip diseases, the process of osteolysis and implant loosening remains a significant problem, especially in young and high-demand patients. More than 40 years ago, ceramic bearings were introduced due to their mechanical advantage in order to obtain a reduction in wear debris, and due to the conviction that it was possible to minimize friction and wear owing to their mechanical hardness, high chemical stability, surface lubrication by fluids and low friction coefficient. Together with excellent mechanical properties, ceramics have a biological inertness: eventual ceramic debris will lead to a reactive response with a high predominance of fibrocystic cells, rather than macrophagic cells, and absence of giant cells, which is ideal from a biological perspective. As a consequence, they will not trigger the granulomatous reaction necessary to induce periprosthetic osteolysis, and this clearly appears to be of great clinical relevance. In recent years, tribology in manufacturing ceramic components has progressed with significant improvements, owing to the development of the latest generation of ceramic composites that allow for an increased material density and reduced grain size. Currently, ceramic-on-ceramic bearings are considered the attractive counterparts of ceramic- or metal-on-polyethylene ones for patients with a long life expectancy. The aim of this paper is to report the results of total hip replacements performed with a ceramic-on-ceramic articulation made from a ceramic composite in a single center, focusing on its usefulness in specific preoperative diagnosis.
      Citation: Journal of Composites Science
      PubDate: 2021-12-08
      DOI: 10.3390/jcs5120320
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 321: Confinement in Extruded Nanocomposites
           Based on PCL and Mesoporous Silicas: Effect of Pore Sizes and Their
           Influence in Ultimate Mechanical Response

    • Authors: Tamara M. Díez-Rodríguez, Enrique Blázquez-Blázquez, Nadine L. C. Antunes, Maria do Rosário Ribeiro, Ernesto Pérez, María L. Cerrada
      First page: 321
      Abstract: In this study, nanocomposites based on polycaprolactone (PCL) and two types of mesoporous silicas, MCM-41 and SBA-15, were attained by melt extrusion. The effect of the silica incorporated within the PCL matrix was observed, firstly, in the morphological characteristics and degradation behavior of the resultant composites. DSC experiments provided information on the existence of confinement in the PCL–SBA-15 materials through the appearance of an additional small endotherm, located at about 25–50 °C, and attributed to the melting of constrained crystallites. Displacement to a slightly lower temperature of this endothermic event was observed in the first heating run of PCL–MCM-41 composites, attributed to the inferior pore size in the MCM-41 particles. Thus, this indicates variations in the inclusion of PCL chains within these two mesostructures with different pore sizes. Real-time variable-temperature small-angle X-ray scattering (SAXS) experiments with synchrotron radiation were crucial to confirm the presence of PCL within MCM-41 and SBA-15 pores. Accurate information was also deduced from these measurements regarding the influence of these two mesoporous MCM-41 and SBA-15 silicas on PCL long spacing. The differences found in these morphological and structural features were responsible for the ultimate mechanical response exhibited by the two sets of PCL nanocomposites, with a considerably higher increase of mechanical parameters in the SBA-15 family.
      Citation: Journal of Composites Science
      PubDate: 2021-12-10
      DOI: 10.3390/jcs5120321
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 322: Polymerization Shrinkage, Hygroscopic
           Expansion, Elastic Modulus and Degree of Conversion of Different
           Composites for Dental Application

    • Authors: Alexandre Luiz Souto Borges, Amanda Maria de Oliveira Dal Piva, Sabrina Elise Moecke, Raquel Coutinho de Morais, João Paulo Mendes Tribst
      First page: 322
      Abstract: Objectives: To characterize the mechanical properties of different resin-composites for dental application. Methods: Thirteen universal dentin shade composites (n = 10) from different manufacturers were evaluated (4 Seasons, Grandio, Venus, Amelogen Plus, P90, Z350, Esthet-X, Amaris, Vita-l-escence, Natural-Look, Charisma, Z250 and Opallis). The polymerization shrinkage percentage was calculated using a video-image recording device (ACUVOL—Bisco Dental) and the hygroscopic expansion was measured after thermocycling aging in the same equipment. Equal volumes of material were used and, after 5 min of relaxation, baseline measurements were calculated with 18 J of energy delivered from the light-curing unit. Specimens were stored in a dry-dark environment for 24 h then thermocycled in distilled water (5–55 °C for 20,000 cycles) with volume measurement at each 5000 cycles. In addition, the pulse-excitatory method was applied to calculate the elastic modulus and Poisson ratio for each resin material and the degree of conversion was evaluated using Fourier transform infrared spectroscopy. Results: The ANOVA showed that all composite volumes were influenced by the number of cycles (α = 0.05). Volumes at 5 min post-polymerization (12.47 ± 0.08 cm3) were significantly lower than those at baseline (12.80 ± 0.09 cm3). With regard to the impact of aging, all resin materials showed a statistically significant increase in volume after 5000 cycles (13.04 ± 0.22 cm3). There was no statistical difference between volumes measured at the other cycle steps. The elastic modulus ranged from 22.15 to 10.06 GPa and the Poisson ratio from 0.54 to 0.22 with a significant difference between the evaluated materials (α = 0.05). The degree of conversion was higher than 60% for all evaluated resin composites.
      Citation: Journal of Composites Science
      PubDate: 2021-12-10
      DOI: 10.3390/jcs5120322
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 323: Technological Aspects of Producing
           Surface Composites by Friction Stir Processing—A Review

    • Authors: Józef Iwaszko, Moosa Sajed
      First page: 323
      Abstract: FSP (friction stir processing) technology is a modern grain refinement method that is setting new trends in surface engineering. This technology is used not only to modify the microstructure of the surface layer of engineering materials, but increasingly more often also to produce surface composites. The application potential of FSP technology lies in its simplicity and speed of processing and in the wide range of materials that can be used as reinforcement in the composite. There are a number of solutions enabling the effective and controlled introduction of the reinforcing phase into the plasticized matrix and the production of the composite microstructure in it. The most important of them are the groove and hole methods, as well as direct friction stir processing. This review article discusses the main and less frequently used methods of producing surface composites using friction stir processing, indicates the main advantages, disadvantages and application limitations of the individual solutions, in addition to potential difficulties in effective processing. This information can be helpful in choosing a solution for a specific application.
      Citation: Journal of Composites Science
      PubDate: 2021-12-11
      DOI: 10.3390/jcs5120323
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 324: Buckling Optimization of Variable
           Stiffness Composite Panels for Curvilinear Fibers and Grid Stiffeners

    • Authors: Sofía Arranz, Abdolrasoul Sohouli, Afzal Suleman
      First page: 324
      Abstract: Automated Fiber Placement (AFP) machines can manufacture composite panels with curvilinear fibers. In this article, the critical buckling load of grid-stiffened curvilinear fiber composite panels is maximized using a genetic algorithm. The skin is composed of layers in which the fiber orientation varies along one spatial direction. The design variables are the fiber orientation of the panel for each layer and the stiffener layout. Manufacturing constraints in terms of maximum curvature allowable by the AFP machine are imposed for both skin and stiffener fibers. The effect of manufacturing-induced gaps in the laminates is also incorporated. The finite element method is used to perform the buckling analyses. The panels are subjected to in-plane compressive and shear loads under several boundary conditions. Optimization results show that the percentage difference in the buckling load between curvilinear and straight fiber panels depends on the load case and boundary conditions.
      Citation: Journal of Composites Science
      PubDate: 2021-12-15
      DOI: 10.3390/jcs5120324
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 325: Additive Manufacturing of Carbon Fiber
           Reinforced Plastic Composites: The Effect of Fiber Content on Compressive
           Properties

    • Authors: Olusanmi Adeniran, Weilong Cong, Eric Bediako, Victor Aladesanmi
      First page: 325
      Abstract: The additive manufacturing (AM) of carbon fiber reinforced plastic (CFRP) composites continue to grow due to the attractive strength-to-weight and modulus-to-weight ratios afforded by the composites combined with the ease of processibility achievable through the AM technique. Short fiber design factors such as fiber content effects have been shown to play determinant roles in the mechanical performance of AM fabricated CFRP composites. However, this has only been investigated for tensile and flexural properties, with no investigations to date on compressive properties effects of fiber content. This study examined the axial and transverse compressive properties of AM fabricated CFRP composites by testing CF-ABS with fiber contents from 0%, 10%, 20%, and 30% for samples printed in the axial and transverse build orientations, and for axial tensile in comparison to the axial compression properties. The results were that increasing carbon fiber content for the short-fiber thermoplastic CFRP composites slightly reduced compressive strength and modulus. However, it increased ductility and toughness. The 20% carbon fiber content provided the overall content with the most decent compressive properties for the 0–30% content studied. The AM fabricated composite demonstrates a generally higher compressive property than tensile property because of the higher plastic deformation ability which characterizes compression loaded parts, which were observed from the different failure modes.
      Citation: Journal of Composites Science
      PubDate: 2021-12-16
      DOI: 10.3390/jcs5120325
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 326: Evaluation of Freeze Drying and
           Electrospinning Techniques for Saffron Encapsulation and Storage Stability
           of Encapsulated Bioactives

    • Authors: Fatemeh Golpira, Neda Maftoonazad, Hosahalli S. Ramaswamy
      First page: 326
      Abstract: Saffron extract was encapsulated into a gelatin matrix by means of electrospinning and freeze drying techniques and the degradation kinetics of bioactive compounds were evaluated during their storage at 4, 24, and 35 °C as compared to non-encapsulated control. The encapsulation efficiency, thermal properties, storage stability, morphology, and diameter distribution of the encapsulated saffron extract were evaluated as output parameters. In general, both encapsulation techniques demonstrated superior retention of bioactive compounds compared to samples without encapsulation during the entire storage period. Electrospinning and freeze drying techniques were able to retain at least 96.2 and 93.7% of crocin, respectively, after 42 days of storage at 35 °C with the 15% saffron extract. The half-life (t1/2) time parameter for the control sample (with 15% saffron extract without encapsulation) was 22 days at 4 °C temperature, while that encapsulated by electrospinning was 138 days and that obtained for freeze drying was 77 days, The half-lives were longer at lower temperatures. The encapsulation efficiency of crocin, picrocrocin, and safranal associated with the electro-spun gelatin fibers were 76.3, 86.0, and 74.2%, respectively, and in comparison, the freeze drying encapsulation efficiencies were relatively lower, at 69.0, 74.7, and 65.8%, respectively. Electro-spun gelatin fibers also had higher melting and denaturation temperatures of 78.3 °C and 108.1 °C, respectively, as compared to 65.4 °C and 93.2 °C, respectively, for freeze-dried samples. Thus, from all respects, it was concluded that electrospinning was a better and more effective technique than freeze drying in terms of preserving saffron bioactive compounds.
      Citation: Journal of Composites Science
      PubDate: 2021-12-17
      DOI: 10.3390/jcs5120326
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 327: Effect of Surface Polishing on
           Nano-Hardness and Elastic Modulus of Different Resin Composites after
           Immersion in Alcoholic Medium

    • Authors: Dhaifallah Alqarni, Ali Alghamdi, Amr Saad, Abdullah Ali H. Alzahrani, Keiichi Hosaka
      First page: 327
      Abstract: There has been a great tendency toward using resin composite in dentistry and exploring nano-hardness, elastic modulus, and effect of polishing on its mechanical properties after its artificial ageing. This study aimed to evaluate the effect of surface polishing of four different resin composites on their nano-hardness and elastic modulus. This effect was tested right after light curing of composite resin and after its artificial ageing (immersion in alcoholic medium). Nanoindentation test preparations, surface roughness, surface hardness, and scanning electron microscope were conducted across the four different resin composites: Clearfil AP-X (APX), Estelite Sigma Quick (ESQ), Beautifil II (BE2), and FiltekTM Supreme Ultra Universal restorative (FSU). We found that difference in fillers load and particle size are amongst the factors influencing hardness and modulus of elasticity. The APX is the highest in term of hardness due to fillers load and size while the ESQ is the lowest because all fillers in nano size and distributed homogenously. The significance of surface polishing of the studied resin composite restorations was highlighted. Future research may focus on exploring survival rate of polished and non-polished composite surfaces with emphasis on measuring degree of conversion and impacts of polished and non-polished surfaces on the individuals’ oral health quality of life.
      Citation: Journal of Composites Science
      PubDate: 2021-12-18
      DOI: 10.3390/jcs5120327
      Issue No: Vol. 5, No. 12 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 285: Crashworthiness of a Composite Bladder
           Fuel Tank for a Tilt Rotor Aircraft

    • Authors: Carmen Simona Paciello, Claudio Pezzella, Marika Belardo, Simone Magistro, Francesco Di Caprio, Vincenzo Musella, Giuseppe Lamanna, Luigi Di Palma
      First page: 285
      Abstract: The fulfilment of the crash is a demanding requirement for a Tiltrotor. Indeed, such a kind of aircraft, being a hybrid between an airplane and a helicopter, inherits the requirements mainly from helicopters (EASA CS 29) due to its hovering ability. In particular, the fuel storage system must be designed in such a manner that it is crash resistant, under prescribed airworthiness requirements, in order to avoid the fuel leakage during such an event, preventing fire and, thus, increasing the survival chances of the crew and the passengers. The present work deals with the evaluation of crashworthiness of the fuel storage system of a Tiltrotor (bladder tank), and, in particular, it aims at describing the adopted numerical approach and some specific results. Crash resistance requirements are considered from the earliest design stages, and for this reason they are mainly addressed from a numerical point of view and by simulations that treat both single components and small/medium size assemblies. The developed numerical models include all the main parts needed for simulating the structural behavior of the investigated wing section: the tank, the structural components of the wing, the fuel sub-systems (fuel lines, probes, etc.) and the fuel itself. During the crash event there are several parts inside the tanks that can come into contact with the tank structure; therefore, it is necessary to evaluate which of these parts can be a damage source for the tank itself and could generate fuel loss. The SPH approach has been adopted to discretise fuel and to estimate the interaction forces with respect to the tank structure. Experimental data were used to calibrate the fuel tank and foam material models and to define the acceleration time-history to be applied. Thanks to the optimized foam’s configuration, the amount of dissipated impact energy is remarkable, and the evaluation of tanks/fuel system stress distribution allows estimating any undesired failure due to a survivable crash event.
      Citation: Journal of Composites Science
      PubDate: 2021-10-22
      DOI: 10.3390/jcs5110285
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 286: Mechanical and Microstructural
           Assessment of Inhomogeneities in Oxide Ceramic Matrix Composites Detected
           by Air-Coupled Ultrasound Inspection

    • Authors: Jan Roßdeutscher, Peter Mechnich, Ferdinand Flucht, Yuan Shi, Raouf Jemmali
      First page: 286
      Abstract: Ceramic Matrix Composites (CMC) are promising materials for high-temperature applications where damage tolerant failure behavior is required. Non-destructive testing is essential for process development, monitoring, and quality assessment of CMC parts. Air-coupled ultrasound (ACU) is a fast and cost-efficient tool for non-destructive inspections of large components with respect to the detection of material inhomogeneities. Even though ACU inspection is usually used for visual inspection, the interpretation of C-scan images is often ambiguous with regard to critical defects and their impact on local material properties. This paper reports on a new approach to link the local acoustic damping of an oxide CMC plate obtained from ACU analysis with subsequent destructive mechanical testing and microstructural analyses. Local damping values of bending bars are extracted from ACU maps and compared with the results of subsequent resonant frequency damping analysis and 3-point bending tests. To support data interpretation, the homogeneous and inhomogeneous CMC areas detected in the ACU map are further analyzed by X-ray computed tomography and scanning electron microscopy. The results provide strong evidence that specific material properties such as Young’s modulus are not predictable from ACU damping maps. However, ACU shows a high, beneficial sensitivity for narrow but large area matrix cracks or delaminations, i.e., local damping is significantly correlated with specific properties such as shear moduli and bending strengths.
      Citation: Journal of Composites Science
      PubDate: 2021-10-23
      DOI: 10.3390/jcs5110286
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 287: Low-Frequency Magnetoelectric Effects
           in Magnetostrictive–Piezoelectric Bilayers: Longitudinal and Bending
           Deformations

    • Authors: Dmitry Filippov, Ying Liu, Peng Zhou, Bingfeng Ge, Jiahui Liu, Jitao Zhang, Tianjin Zhang, Gopalan Srinivasan
      First page: 287
      Abstract: A model for the low-frequency magnetoelectric (ME) effect that takes into consideration the bending deformation in a ferromagnetic and ferroelectric bilayer is presented. Past models, in general, ignored the influence of bending deformation. Based on the solution of the equations of the elastic theory and electrostatics, expressions for the ME voltage coefficients (MEVCs) and ME sensitivity coefficients (MESCs) in terms of the physical parameters of the materials and the geometric characteristic of the structure were obtained. Contributions from both bending and planar deformations were considered. The theory was applied to composites of PZT and Ni with negative magnetostriction, and Permendur, or Metglas, both with positive magnetostriction. Estimates of MEVCs and MESCs indicate that the contribution from bending deformation is significant but smaller than the contribution from planar deformations, leading to a reduction in the net ME coefficients in all the three bilayer systems.
      Citation: Journal of Composites Science
      PubDate: 2021-10-28
      DOI: 10.3390/jcs5110287
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 288: Advances on Dye-Sensitized Solar Cells
           (DSSCs) Nanostructures and Natural Colorants: A Review

    • Authors: José A. Castillo-Robles, Enrique Rocha-Rangel, José A. Ramírez-de-León, Frida C. Caballero-Rico, Eddie N. Armendáriz-Mireles
      First page: 288
      Abstract: Human beings are attempting to take advantage of renewable natural resources by using solar cells. These devices take the sun’s radiation and convert it into electrical energy. The issue with traditional silicon-based solar cells is their manufacturing costs and environmental problems. For this reason, alternatives have been developed within the solar cell field. One of these alternatives is the dye-sensitized solar cell (DSSC), also known as Grätzel solar cells. DSSCs are a type of solar cell that mimics photosynthesis. They have a photoanode, which is formed by a semiconductor film sensitized with a dye. Some of their advantages include low-cost manufacturing, eco-friendly materials use, and suitability for most environments. This review discusses four important aspects, with two related to the dye, which can be natural or synthetic. Herein, only natural dyes and their extraction methods were selected. On the other hand, this paper discusses the nanostructures used for DSSCs, the TiO2 nanostructure being the most reported; it recently reached an efficiency level of 10.3%. Finally, a review on the novelties in DSSCs technology is presented, where it is observed that the use of Catrin protein (cow brain) shows 1.45% of efficiency, which is significantly lower if compared to Ag nanoparticles doped with graphene that report 9.9% efficiency.
      Citation: Journal of Composites Science
      PubDate: 2021-10-29
      DOI: 10.3390/jcs5110288
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 289: Experimental and Numerical Analysis of
           Mold Filling in Rotational Molding

    • Authors: Jonas Nieschlag, Julian Seuffert, Daniel Strack, Marco Friedmann, Luise Kärger, Frank Henning, Jürgen Fleischer
      First page: 289
      Abstract: This work focuses on the development of a numerical mold filling simulation for the rotational molding process. In the rotational molding process, a dry fiber preform is placed in a mold and impregnated with a thermoset matrix under rotation. Additionally, metallic load introduction elements can be inserted into the mold and joined with co-curing or form-fit, resulting in hybrid drive shafts or tie rods. The numerical model can be used to simulate the impregnation of the preform. Based on the resin transfer molding process, an OpenFOAM solver is extended for the rotational molding process. Permeability, kinetic and curing models are selected and adapted to the materials used. A wireless measurement solution with a capacitive sensor is developed to validate the model. Comparisons between measurements and numerically calculated impregnation times to reach the capacitive sensor with the matrix show good quality of the developed model. The average deviation between calculated result and measured mean values in the experiment is 43.8% the maximum deviation is 65.8% . The model can therefore be used to predict the impregnation progress and the curing state.
      Citation: Journal of Composites Science
      PubDate: 2021-11-04
      DOI: 10.3390/jcs5110289
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 290: State-of-the-Art Review on
           Experimental Investigations of Textile-Reinforced Concrete Exposed to High
           Temperatures

    • Authors: Panagiotis Kapsalis, Tine Tysmans, Danny Van Hemelrijck, Thanasis Triantafillou
      First page: 290
      Abstract: Textile-reinforced concrete (TRC) is a promising composite material with enormous potential in structural applications because it offers the possibility to construct slender, lightweight, and robust elements. However, despite the good heat resistance of the inorganic matrices and the well-established knowledge on the high-temperature performance of the commonly used fibrous reinforcements, their application in TRC elements with very small thicknesses makes their effectiveness against thermal loads questionable. This paper presents a state-of-the-art review on the thermomechanical behavior of TRC, focusing on its mechanical performance both during and after exposure to high temperatures. The available knowledge from experimental investigations where TRC has been tested in thermomechanical conditions as a standalone material is compiled, and the results are compared. This comparative study identifies the key parameters that determine the mechanical response of TRC to increased temperatures, being the surface treatment of the textiles and the combination of thermal and mechanical loads. It is concluded that the uncoated carbon fibers are the most promising solution for a fire-safe TRC application. However, the knowledge gaps are still large, mainly due to the inconsistency of the testing methods and the stochastic behavior of phenomena related to heat treatment (such as spalling).
      Citation: Journal of Composites Science
      PubDate: 2021-11-05
      DOI: 10.3390/jcs5110290
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 291: Numerical Application of Effective
           Thickness Approach to Box Aluminium Sections

    • Authors: Elide Nastri, Vincenzo Piluso, Alessandro Pisapia
      First page: 291
      Abstract: The ultimate behaviour of aluminium members subjected to uniform compression or bending is strongly influenced by local buckling effects which occur in the portions of the section during compression. In the current codes, the effective thickness method (ETM) is applied to evaluate the ultimate resistance of slender cross-sections affected by elastic local buckling. In this paper, a recent extension of ETM is presented to consider the local buckling effects in the elastic-plastic range and the interaction between the plate elements constituting the cross-section. The theoretical results obtained with this approach, applied to box-shaped aluminium members during compression or in bending, are compared with the experimental tests provided in the scientific literature. It is observed that the ETM is a valid and accurate tool for predicting the maximum resistance of box-shaped aluminium members during compression or in bending.
      Citation: Journal of Composites Science
      PubDate: 2021-11-05
      DOI: 10.3390/jcs5110291
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 292: Conjugated Polymer/Graphene Oxide
           Nanocomposites—State-of-the-Art

    • Authors: Ayesha Kausar
      First page: 292
      Abstract: Graphene oxide is an imperative modified form of graphene. Similar to graphene, graphene oxide has gained vast interest for the myriad of industrial applications. Conjugated polymers or conducting polymers are well known organic materials having conducting backbone. These polymers have semiconducting nature due to π-conjugation along the main chain. Doping and modification have been used to enhance the electrical conductivity of the conjugated polymers. The nanocomposites of the conjugated polymers have been reported with the nanocarbon nanofillers including graphene oxide. This review essentially presents the structure, properties, and advancements in the field of conducting polymer/graphene oxide nanocomposites. The facile synthesis, processability, and physical properties of the polymer/graphene oxide nanocomposites have been discussed. The conjugated polymer/graphene oxide nanocomposites have essential significance for the supercapacitors, solar cells, and anti-corrosion materials. Nevertheless, the further advanced properties and technical applications of the conjugated polymer/graphene oxide nanocomposites need to be explored to overcome the challenges related to the high performance.
      Citation: Journal of Composites Science
      PubDate: 2021-11-05
      DOI: 10.3390/jcs5110292
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 293: Preliminary Finite Element Analysis
           and Flight Simulations of a Modular Drone Built through Fused Filament
           Fabrication

    • Authors: Salvatore Brischetto, Roberto Torre
      First page: 293
      Abstract: This paper discusses the architecture and preliminary design of an Unmanned Aerial Vehicle (UAV), whose actual operative scenario and required performances drive its flying configuration. The UAV is a multirotor and can be adapted to be used as a tricopter, a quadcopter, a hexacopter, and an octocopter: the number (and consequent arrangement) of the arms modify its performance. Customization is combined with the concept of additive manufacturing, as all components are designed to be produced in Fused Filament Fabrication (FFF). This approach does not limit the application scenarios of the drone; it is instead a further push in the direction of customization, as it permits continuous upgrades over time. The paper simulates four scenarios and discusses how to optimize performances such as payload, thrust-to-weight ratio, efficiency, flight time, and maximum speed through suitable configurations. Avionic components already available on the market integrate into a customizable and adaptable frame. This analysis reveals the most severe conditions for the structure, and conducts a structural validation of its performance. Validating the functional use of FFF-produced parts is challenging due to the anisotropic behavior of the parts. However, some structural elements are thin-walled and enjoy being printed with a 100% linear infill. A simplified approach to those elements has already been proposed and validated through a parallel with UniDirectional Composites, whose 2D testing procedures and methodologies have been derived and adapted. An FEA of some elements of the frame is conducted, using shell elements to discretize the geometry. A proper definition of their mechanical response is possible because the constitutive model is not isotropic a priori but reflects the behavior of the finished parts. The tensile strength variability in the material reference system is high: a component-by-component comparison proves the design to be adequate and measured to the surrounding conditions; however, it highlights the absence of a defined failure criterion.
      Citation: Journal of Composites Science
      PubDate: 2021-11-06
      DOI: 10.3390/jcs5110293
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 294: Design of Low Cost Carbon Fiber
           Composites via Examining the Micromechanical Stress Distributions in A42
           Bean-Shaped versus T650 Circular Fibers

    • Authors: Imad Hanhan, Michael D. Sangid
      First page: 294
      Abstract: Recent advancements have led to new polyacrylonitrile carbon fiber precursors which reduce production costs, yet lead to bean-shaped cross-sections. While these bean-shaped fibers have comparable stiffness and ultimate strength values to typical carbon fibers, their unique morphology results in varying in-plane orientations and different microstructural stress distributions under loading, which are not well understood and can limit failure strength under complex loading scenarios. Therefore, this work used finite element simulations to compare longitudinal stress distributions in A42 (bean-shaped) and T650 (circular) carbon fiber composite microstructures. Specifically, a microscopy image of an A42/P6300 microstructure was processed to instantiate a 3D model, while a Monte Carlo approach (which accounts for size and in-plane orientation distributions) was used to create statistically equivalent A42/P6300 and T650/P6300 microstructures. First, the results showed that the measured in-plane orientations of the A42 carbon fibers for the analyzed specimen had an orderly distribution with peaks at ϕ =0∘,180∘. Additionally, the results showed that under 1.5% elongation, the A42/P6300 microstructure reached simulated failure at approximately 2108 MPa, while the T650/P6300 microstructure did not reach failure. A single fiber model showed that this was due to the curvature of A42 fibers which was 3.18 μm−1 higher at the inner corner, yielding a matrix stress that was 7 MPa higher compared to the T650/P6300 microstructure. Overall, this analysis is valuable to engineers designing new components using lower cost carbon fiber composites, based on the micromechanical stress distributions and unique packing abilities resulting from the A42 fiber morphologies.
      Citation: Journal of Composites Science
      PubDate: 2021-11-07
      DOI: 10.3390/jcs5110294
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 295: Wrinkle Formation and Initial Defect
           Sensitivity of Steered Tow in Automated Fiber Placement

    • Authors: Meisam Kheradpisheh, Mehdi Hojjati
      First page: 295
      Abstract: This paper aims to study the wrinkle formation of a prepreg with initial defect during steering in automated fiber placement (AFP). Wrinkle formation has a detrimental effect on the mechanical properties of the final product, limiting the AFP applications. A theoretical model for wrinkle formation has been developed in which a Pasternak foundation and a Koiter imperfection model are adapted to model viscoelastic characteristics of the prepreg tack and initial defect of the prepreg, respectively. The initial defect is defined as a slight deviation of the tow’s mid-plane from a horizontal shape. The initial defect is generated in the tow by moving the tow through the guidance system, pressure of the roller, and resin tackiness. Galerkin method, along with the finite difference method (FDM), are employed to solve the wrinkle problem equation. The proposed method is able to satisfy the different boundary conditions for the wrinkle problem completely. The numerical results show that increasing the initial defect leads to a decrease in critical load and an increase in critical steering radius. To validate the theoretical model, experimental results are presented and compared with model-predicted results. It is shown that the model is well able to capture the trends and values of wrinkle formation wavelengths obtained from the experiment.
      Citation: Journal of Composites Science
      PubDate: 2021-11-09
      DOI: 10.3390/jcs5110295
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 296: An Experimental Study of the Cyclic
           Compression after Impact Behavior of CFRP Composites

    • Authors: Raffael Bogenfeld, Christopher Gorsky
      First page: 296
      Abstract: The behavior of impact damaged composite laminates under cyclic load is crucial to achieve a damage tolerant design of composite structures. A sufficient residual strength has to be ensured throughout the entire structural service life. In this study, a set of 27 impacted coupon specimens is subjected to quasi-static and cyclic compression load. After long intervals without detectable damage growth, the specimens fail through the sudden lateral propagation of delamination and fiber kink bands within few load cycles. Ultrasonic inspections were used to reveal the damage size after certain cycle intervals. Through continuous dent depth measurements during the cyclic tests, the evolution of the dent visibility was monitored. These measurements revealed a relaxation of the indentation of up to 90% before ultimate failure occurs. Due to the distinct relaxation and the short growth interval before ultimate failure, this study confirms the no-growth design approach as the preferred method to account for the damage tolerance of stiffened, compression-loaded composite laminates.
      Citation: Journal of Composites Science
      PubDate: 2021-11-10
      DOI: 10.3390/jcs5110296
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 297: Tension-Compression Fatigue Induced
           Stress Concentrations in Woven Composite Laminate

    • Authors: Eldho Mathew, Rajaram Attukur Nandagopal, Sunil Chandrakant Joshi, Pinter Armando, Pasi Matteo
      First page: 297
      Abstract: Tension-compression (T-C) fatigue response is one of the important design criteria for carbon-fibre-reinforced polymer (CFRP) material, as well as stress concentration. Hence, the objective of the current study is to investigate and quantify the stress concentration in CFRP dog-bone specimens due to T-C quasi-static and fatigue loadings (with anti-buckling fixtures). Dog-bone specimens with a [(0/90),(45/−45)4]s layup were fabricated using woven CFRP prepregs and their low-cycle fatigue behaviour was studied at two stress ratios (−0.1 & −0.5) and two frequencies (3 Hz & 5 Hz). During testing, strain gauges were mounted at the centre and edge regions of the dog-bone specimens to obtain accurate, real-time strain measurements. The corresponding stresses were calculated using Young’s moduli. The stress concentration at the specimen edges, due to quasi-static tension, was significant compared to quasi-static compression loads. Furthermore, the stress concentration increased with the quasi-static loading within the elastic limit. Similarly, the stress concentration at the specimen edges, due to tensile fatigue loads, was more significant and consistent than due to compressive fatigue loads. Finally, the effects of the stress ratio and loading frequency on the stress concentration were noted to be negligible.
      Citation: Journal of Composites Science
      PubDate: 2021-11-11
      DOI: 10.3390/jcs5110297
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 298: In Vitro Weight Loss of Dental
           Composite Resins and Glass-Ionomer Cements Exposed to a Challenge
           Simulating the Oral Intake of Acidic Drinks and Foods

    • Authors: Marco Colombo, Simone Gallo, Marco Chiesa, Claudio Poggio, Andrea Scribante, Paolo Zampetti, Giampiero Pietrocola
      First page: 298
      Abstract: Specific conditions of the oral cavity, such as intake of acidic drinks, foods, and drugs, represent a damage both for teeth as well as restorative materials. The aim of this in vitro study is to assess the influence of an acidic challenge on the weight loss of biomimetic restorative dental materials (composite resins and glass-ionomer cements, respectively). Seven products recently available in the marked have been tested in this study for the two kinds of materials, respectively. Resin composites were divided into Groups 1A–7A, whereas glass-ionomer cements into Groups 1B–7B. A total of six samples was considered for each group, among which two were stored into distilled water (control samples) whereas the other four were immersed into soft drink (Coca-Cola, Coca-Cola Company, Milano, Italy) for 7 days. Respectively, after 1, 3 and 7 days, weight was assessed for each sample and the percentage weight loss was calculated. For all the composite resins (Groups 1A–7A), no significant intergroup or intragroup differences occurred for the weight loss values (p > 0.05). Conversely, all glass-ionomers (Groups 1B–7B) showed a significant and progressive weight loss after 1, 3, and 7 days of acid challenge (p < 0.05) (intragroup differences). This reduction was significantly lower in case of GC Equia Forte + Coat and ChemFil Rock, with respect to the other cements (p < 0.05) (intergroup differences). In conclusions, all the biomimetic composite resins showed a reliable behavior when exposed to acidic erosion, whereas glass-ionomers cements generally tended to solubilize. However, the additional use of a protective layer above these latter materials could reduce this event. Despite these results appear to be interesting from a clinical point of view, future morphological evaluations should be conducted to evaluate the superficial changes of the materials after acidic explosion.
      Citation: Journal of Composites Science
      PubDate: 2021-11-13
      DOI: 10.3390/jcs5110298
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 299: Mechanical Properties of Compression
           Moulded Aggregate-Reinforced Thermoplastic Composite Scrap

    • Authors: Julien Moothoo, Mahadev Bar, Pierre Ouagne
      First page: 299
      Abstract: Recycling of thermoplastic composites has drawn a considerable attention in the recent years. However, the main issue with recycled composites is their inferior mechanical properties compared to the virgin ones. In this present study, an alternative route to the traditional mechanical recycling technique of thermoplastic composites has been investigated with the view to increase mechanical properties of the recycled parts. In this regard, the glass/polypropylene laminate offcuts are cut in different grain sizes and processed in bulk form, using compression moulding. Further, the effect of different grain sizes (i.e., different lengths, widths and thicknesses) and other process-related parameters (such as mould coverage) on the tensile properties of recycled aggregate-reinforced composites have been investigated. The tensile properties of all composite samples are tested according to ISO 527-4 test method and the significance of test results is evaluated according to Student’s t-test and Fisher’s F-test respectively. It is observed that the tensile moduli of the recycled panels are close to the equivalent quasi-isotropic continuous fibre-reinforced reference laminate while there is a noteworthy difference in the strengths of the recycled composites. At this stage, the manufactured recycled composites show potential for stiffness-driven application.
      Citation: Journal of Composites Science
      PubDate: 2021-11-14
      DOI: 10.3390/jcs5110299
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 300: Compatibilization of Starch/Synthetic
           Biodegradable Polymer Blends for Packaging Applications: A Review

    • Authors: Oneesha H. P. Gunawardene, Chamila Gunathilake, Sumedha M. Amaraweera, Nimasha M. L. Fernando, Darshana B. Wanninayaka, Asanga Manamperi, Asela K. Kulatunga, Suranga M. Rajapaksha, Rohan S. Dassanayake, Chakrawarthige A. N. Fernando, Aruna Manipura
      First page: 300
      Abstract: The health and environmental concerns of the usage of non-biodegradable plastics have driven efforts to explore replacing them with renewable polymers. Although starch is a vital renewable polymer, poor water resistivity and thermo-mechanical properties have limited its applications. Recently, starch/synthetic biodegradable polymer blends have captured greater attention to replace inert plastic materials; the question of ‘immiscibility’ arises during the blend preparation due to the mixing of hydrophilic starch with hydrophobic polymers. The immiscibility issue between starch and synthetic polymers impacts the water absorption, thermo-mechanical properties, and chemical stability demanded by various engineering applications. Numerous studies have been carried out to eliminate the immiscibility issues of the different components in the polymer blends while enhancing the thermo-mechanical properties. Incorporating compatibilizers into the blend mixtures has significantly reduced the particle sizes of the dispersed phase while improving the interfacial adhesion between the starch and synthetic biodegradable polymer, leading to fine and homogeneous structures. Thus, Significant improvements in thermo-mechanical and barrier properties and water resistance can be observed in the compatibilized blends. This review provides an extensive discussion on the compatibilization processes of starch and petroleum-based polymer blends.
      Citation: Journal of Composites Science
      PubDate: 2021-11-16
      DOI: 10.3390/jcs5110300
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 301: Automated Damage Detection of
           (C/C)/Si/SiC Composite Using Vibration Modes with Deep Neural Networks

    • Authors: Chihiro Shibata, Naohiro Shichijo, Johei Matsuoka, Yuriko Takeshima, Jenn-Ming Yang, Yoshihisa Tanaka, Yutaka Kagawa
      First page: 301
      Abstract: Discontinuous carbon fiber-carbon matrix composites dispersed Si/SiC matrix composites have complicated microstructures that consist of four phases (C/C, Si, SiC, and C/SiC). The crack stability significantly depends on their geometrical arrangement. Nondestructive evaluation is needed to maintain the components in their safe condition. Although several nondestructive evaluation methods such as the Eddy current have been developed, any set of them is still inadequate in order to cover all of the scales and aspects that (C/C)/Si/SiC composites comprise. We propose a new method for nondestructive evaluation using vibration/resonance modes and deep learning. The assumed resolution is mm-order (approx. 1–10 mm), which laser vibrometers are generally capable of handling sufficiently. We utilize deep neural networks called convolutional auto-encoders for inferring damaged areas from vibration modes, which is a so-called inverse problem and infeasible to solve numerically in most cases. We solve this inference problem by training convolutional auto-encoders using vibration modes obtained from a non-damaged specimen with various frequencies as the dataset. Experimental results show that the proposed method successfully detects the damaged areas of validation specimens. One of the noteworthy points of this method is that we need only a few specimens for training deep neural networks, which generally require a large amount of data.
      Citation: Journal of Composites Science
      PubDate: 2021-11-16
      DOI: 10.3390/jcs5110301
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 302: Calcium Carbonate Particles Filled
           Homopolymer Polypropylene at Different Loading Levels: Mechanical
           Properties Characterization and Materials Failure Analysis

    • Authors: Yucheng Peng, Munkaila Musah, Brian Via, Xueqi Wang
      First page: 302
      Abstract: Calcium carbonate (CaCO3) particles have been widely used in filling thermoplastics for different applications in automotive, packaging, and construction. No agreement has been reached in the research community regarding the function of CaCO3 for enhancing toughness of homopolymer polypropylene (HPP). This study was to understand the effect of different loading levels of CaCO3 on HPP toughness, including notched and unnotched impact strength. A batch mixer was used to thermally compound CaCO3 particles with HPP at loading levels of 10, 20, 30, 40, and 50 wt.%, followed by specimen preparation using an injection molding process. The mechanical properties of the composites, including tensile, flexural, and impact were characterized. The results indicated that tensile strengths decreased significantly with increasing loading levels of CaCO3 particles while the tensile and flexural modulus increased significantly with increasing particle loadings. The composite tensile properties changed linearly with increasing CaCO3 loadings. The notched Izod impact strength of the composites was sustained by adding CaCO3 particles up to 40 wt.% while the unnotched impact strength decreased significantly with the addition of CaCO3 particles. Different deformation mechanisms between notched (fracture propagation) and unnotched (fracture initiation and propagation) impact tests were proposed to be the reason.
      Citation: Journal of Composites Science
      PubDate: 2021-11-18
      DOI: 10.3390/jcs5110302
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 303: Structural Damage Detection Using
           Supervised Nonlinear Support Vector Machine

    • Authors: Kian K. Sepahvand
      First page: 303
      Abstract: Damage detection, using vibrational properties, such as eigenfrequencies, is an efficient and straightforward method for detecting damage in structures, components, and machines. The method, however, is very inefficient when the values of the natural frequencies of damaged and undamaged specimens exhibit slight differences. This is particularly the case with lightweight structures, such as fiber-reinforced composites. The nonlinear support vector machine (SVM) provides enhanced results under such conditions by transforming the original features into a new space or applying a kernel trick. In this work, the natural frequencies of damaged and undamaged components are used for classification, employing the nonlinear SVM. The proposed methodology assumes that the frequencies are identified sequentially from an experimental modal analysis; for the study propose, however, the training data are generated from the FEM simulations for damaged and undamaged samples. It is shown that nonlinear SVM using kernel function yields in a clear classification boundary between damaged and undamaged specimens, even for minor variations in natural frequencies.
      Citation: Journal of Composites Science
      PubDate: 2021-11-18
      DOI: 10.3390/jcs5110303
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 304: Hybrid Perovskite/Polymer Materials:
           Preparation and Physicochemical Properties

    • Authors: Martha Kafetzi, Stergios Pispas, George Mousdis
      First page: 304
      Abstract: The aim of this work is to investigate the preparation, the optical properties, and the stability over time of a colloidal organic–inorganic hybrid perovskite (CH3NH3PbBr3)/random copolymer P(MMA-co-DMAEMA) system. Different ratios of perovskite to copolymer were used to study its effect on stability and properties. The optical properties were investigated by UV-Vis and fluorescence spectroscopy. Dynamic light scattering was used to determine the size, and the size polydispersity of the colloidal hybrid particles; while morphology was investigated by transmission electron microscopy. Photoluminescence decay studies revealed the interaction of the random copolymer with the perovskite. Finally, thin-films were prepared, to investigate the optical properties of the samples in the absence of the solvent. High temporal stability of the optical properties of thin hybrid films was observed under certain conditions.
      Citation: Journal of Composites Science
      PubDate: 2021-11-19
      DOI: 10.3390/jcs5110304
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 305: Higher-Order Free Vibration Analysis
           of Porous Functionally Graded Plates

    • Authors: Slimane Merdaci, Hadj Mostefa Adda, Belghoul Hakima, Rossana Dimitri, Francesco Tornabene
      First page: 305
      Abstract: The present work analyzes the free vibration response of functionally graded (FG) plates made of Aluminum (Al) and Alumina (Al2O3) with different porosity distributions, as usually induced by a manufacturing process. The problem is tackled theoretically based on a higher-order shear deformation plate theory, while proposing a Navier-type approximation to solve the governing equations for simply-supported plates with different porosity distributions in the thickness direction. The reliability of the proposed theory is checked successfully by comparing the present results with predictions available from literature based on further first-order or higher-order theories. A large parametric study is performed systematically to evaluate the effect of different mechanical properties, such as the material indexes, porosity volume fractions, porosity distributions, and length-to-thickness ratios, on the free vibration response of FG plates, as useful for the design purposes of most engineered materials and composite applications.
      Citation: Journal of Composites Science
      PubDate: 2021-11-21
      DOI: 10.3390/jcs5110305
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 306: Alumina, Zirconia and Their Composite
           Ceramics with Properties Tailored for Medical Applications

    • Authors: Wolfgang Burger, Gundula Kiefer
      First page: 306
      Abstract: Although in 1977 the first ceramic composite material had been introduced into the market, it was a long time before composite materials were qualified for medical applications. For a long period high purity alumina ceramics have been used as ball-heads and cups. Because of their brittleness, in 1986 yttria stabilized zirconia has been introduced into this application, because of higher strength and fracture toughness. However, due to its hydrothermal instability this material disappeared in orthopaedic applications in 2000. Meanwhile a composite materials based on an alumina matrix with dispersed metastable tetragonal zirconia particles and in-situ formed hexagonal platelets became the standard material for ceramic ball-heads, because of their excellent mechanical strength, hardness and improved fracture toughness. Especially fracture toughness can be improved further by special material formulations and tailored microstructure. It has been shown that a mixed stabilisation of zirconia by yttria and ceria with dispersed alumina and hexagonal platelets overcomes the hydrothermal instability and excellent materials properties can be achieved. Such materials do have big potential to be used in dental applications. Furthermore, these materials also can be seen as a new generation for ball-heads, because of their enhanced fracture toughness. All materials are described within these articles. In order to achieve the required properties of the materials, special raw materials are required. Therefore, it is quite important to understand and know the raw material manufacturing procedures.
      Citation: Journal of Composites Science
      PubDate: 2021-11-22
      DOI: 10.3390/jcs5110306
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 267: Synthesis and Characterization of
           Novel Fe3O4/PVA/Eggshell Hybrid Nanocomposite for Photodegradation and
           Antibacterial Activity

    • Authors: Piyush Kumar Gupta, Senthilkumar Palanisamy, Tamilarasi Gopal, Ranjithkumar Rajamani, Soumya Pandit, Somya Sinha, Vijay Kumar Thakur
      First page: 267
      Abstract: In the 21st century, hybrid nanocomposites were widely used in bioelectronic, biosensing, photocatalytic, and biomedical applications. In the present study, we fabricated a novel Fe3O4/PVA/Eggshell hybrid nanocomposite and physicochemically characterized it using powder XRD, EDS, FTIR, VSM, and HR-TEM analysis. The XRD spectrum revealed the crystalline and FCC configuration of Fe3O4 NPs with average crystal size of 16.28 nm, and the HRTEM image indicates the prepared hybrid nanocomposite is of spherical shape with less agglomeration. This hybrid nanocomposite showed a significant photodegradation property in degrading organic pollutants such as congo red and crystal violet dyes under the sunlight irradiation. In addition, the hybrid nanocomposite also displayed a potent antibacterial property against different Gram +ve and Gram −ve bacterial pathogens. This study provides a significant example in the overview of fabrication of cost effectively, eco-friendly, and multiple-application hybrid nanocomposites through eggshell membrane fibers.
      Citation: Journal of Composites Science
      PubDate: 2021-10-12
      DOI: 10.3390/jcs5100267
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 268: Strain-Mediated Magneto-Electric
           Effects in Coaxial Nanofibers of Y/W-Type Hexagonal Ferrites and
           Ferroelectrics

    • Authors: Ying Liu, Peng Zhou, Bingfeng Ge, Jiahui Liu, Jitao Zhang, Wei Zhang, Tianjing Zhang, Gopalan Srinivasan
      First page: 268
      Abstract: Nanofibers of Y- or W-type hexagonal ferrites and core–shell fibers of hexagonal ferrites and ferroelectric lead zirconate titanate (PZT) or barium titanate (BTO) were synthesized by electrospinning. The fibers were found to be free of impurity phases, and the core–shell structure was confirmed by electron and scanning probe microscopy. The values of magnetization of pure hexagonal ferrite fibers compared well with bulk ferrite values. The coaxial fibers showed good ferroelectric polarization, with a maximum value of 0.85 μC/cm2 and 2.44 μC/cm2 for fibers with BTO core–Co2W shell and PZT core–Ni2Y shell structures, respectively. The magnetization, however, was much smaller than that for bulk hexaferrites. Magneto-electric (ME) coupling strength was characterized by measuring the ME voltage coefficient (MEVC) for magnetic field-assembled films of coaxial fibers. Among the fibers with Y-type, films with Zn2Y showed a higher MEVC than films with Ni2Y, and fibers with Co2W had a higher MEVC than that of those with Zn2W. The highest MEVC of 20.3 mV/cm Oe was measured for Co2W–PZT fibers. A very large ME response was measured in all of the films, even in the absence of an external magnetic bias field. The fibers studied here have the potential for use in magnetic sensors and high-frequency device applications.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100268
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 269: Thermal, X-ray Diffraction and
           Oedometric Analyses of Silt-Waste/NaOH-Activated Metakaolin Geopolymer
           Composite

    • Authors: Daniele Moro, Riccardo Fabbri, Jennifer Romano, Gianfranco Ulian, Antonino Calafato, Abbas Solouki, Cesare Sangiorgi, Giovanni Valdrè
      First page: 269
      Abstract: The present research investigates the possibility to create a silt-waste reinforced composite through a NaOH-activated, metakaolin-based geopolymerization process. In this regard, we used thermal exo–endo analysis, X-ray diffraction (XRD), and oedometric mechanical tests to characterize the produced composites. In our experimental conditions, the tested material mixtures presented exothermic peaks with maximum temperatures of about 100 °C during the studied geopolymerization process. In general, the XRD analyses showed the formation of amorphous components and new mineral phases of hydrated sodalite, natrite, thermonatrite and trona. From oedometric tests, we observed a different behavior of vertical deformation related to pressure (at RT) for the various produced composites. The present work indicated that the proposed geopolymerization process to recycle silt-waste produced composite materials with various and extended mineralogy and chemical–physical properties, largely depending on both the precursors and the specific alkaline-activating solution. Thermal analysis, XRD, and oedometric mechanical tests proved to be fundamental to characterize and understand the behavior of the newly formed composite material.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100269
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 270: Effects of Surface Modification with
           Stearic Acid on the Dispersion of Some Inorganic Fillers in PE Matrix

    • Authors: Thanh Tung Nguyen, Van Khoi Nguyen, Thi Thu Ha Pham, Thu Trang Pham, Trung Duc Nguyen
      First page: 270
      Abstract: To evaluate the effects of surface modification with stearic acid on the dispersion of some inorganic fillers in polyethylene (PE) matrix, masterbatches containing 20–40 wt% of stearic acid uncoated and coated inorganic fillers and the linear low-density polyethylene (LLDPE) films containing 3–7% stearic acid uncoated and coated inorganic fillers were prepared. Two types of inorganic fillers used in the masterbatch included bentonite and silica. The structural change of inorganic fillers, whose surface was modified with stearic acid, was studied using IR spectroscopy. The dispersion of inorganic fillers in LLDPE matrix was evaluated using scanning electron microscope (masterbatch samples) and optical microscope (film samples). Changes in the melting temperature of LLDPE in the presence of inorganic fillers were evaluated by using differential scanning calorimeter (DSC). The mechanical properties of the films were evaluated according to ASTM D882. Surface-treated fillers with stearic acid dispersed in the masterbatches and films better than untreated fillers did. Stearic acid did not change the melting temperature of the filler/PE masterbatches. The mechanical properties of the films containing stearic acid coated fillers were higher than those containing unmodified fillers.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100270
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 271: Random Forest Modeling for Fly
           Ash-Calcined Clay Geopolymer Composite Strength Detection

    • Authors: Priyanka Gupta, Nakul Gupta, Kuldeep K. Saxena, Sudhir Goyal
      First page: 271
      Abstract: Geopolymer is an eco-friendly material used in civil engineering works. For geopolymer concrete (GPC) preparation, waste fly ash (FA) and calcined clay (CC) together were used with percentage variation from 5, 10, and 15. In the mix design for geopolymers, there is no systematic methodology developed. In this study, the random forest regression method was used to forecast compressive strength and split tensile strength. The input content involved were caustic soda with 12 M, 14 M, and 16 M; sodium silicate; coarse aggregate passing 20 mm and 10 mm sieve; crushed stone dust; superplasticizer; curing temperature; curing time; added water; and retention time. The standard age of 28 days was used, and a total of 35 samples with a target-specified compressive strength of 30 MPa were prepared. In all, 20% of total data were trained, and 80% of data testing was performed. Efficacy in terms of mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R2), and MSE (mean squared error) is suggested in the model. The results demonstrated that the RFR model is likely to predict GPC compressive strength (MAE = 1.85 MPa, MSE = 0.05 MPa, RMSE = 2.61 MPa, and R2 = 0.93) and split tensile strength (MAE = 0.20 MPa, MSE = 6.83 MPa, RMSE = 0.24 MPa, and R2 = 0.90) during training.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100271
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 272: Effects of Resin/Filler Adhesion on
           the Thermal and Electrical Conductivity of Polyimide Nanocomposites

    • Authors: Yoshimichi Ohki, Naoshi Hirai
      First page: 272
      Abstract: With an aim to develop a good coil winding insulation film, fillers of boehmite alumina in the shape of a roughly rectangular plate were added with ratios of 10 and 20 wt% to polyimide. The filler surface was untreated or treated with a methacrylic or an epoxy silane coupling agent. Such prepared polyimide nanocomposites were subjected to various tests to measure the tensile strength, elastic modulus, complex permittivity, and thermal conductivity. It was found that samples with fillers treated using the methacrylic silane coupling agent have the strongest adhesion at the filler/polyimide interfaces and the lowest dielectric loss factor at high temperatures. A positive relationship between the filler/polyimide adhesion and the thermal conductivity is also indicated. These findings are significant since they indicate that the adhesion status at the filler/polymer interface exerts a strong influence on the thermal and electrical conduction processes in the polymer.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100272
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 273: Is Surface Metastability of Today’s
           Ceramic Bearings a Clinical Issue'

    • Authors: Alessandro Alan Porporati, Laurent Gremillard, Jérôme Chevalier, Rocco Pitto, Marco Deluca
      First page: 273
      Abstract: Recent studies on zirconia-toughened alumina (ZTA) evidenced that in vivo aged implants display a much higher monoclinic zirconia content than expected from in vitro simulations by autoclaving. At the moment, there is no agreement on the source of this discrepancy: Some research groups ascribe it to the effect of mechanical impact shocks, which are generally not implemented in standard in vitro aging or hip walking simulators. Others invoke the effect of metal transfer, which should trigger an autocatalytic reaction in the body fluid environment, accelerating the kinetics of tetragonal-to-monoclinic transformation in vivo. Extrapolations of the aging kinetics from high (autoclave) to in vivo temperature are also often disputed. Last, Raman spectroscopy is by far the preferred method to quantify the amount of monoclinically transformed zirconia. There are, however, many sources of errors that may negatively affect Raman results, meaning that the final interpretation might be flawed. In this work, we applied Raman spectroscopy to determine the monoclinic content in as-received and in vitro aged ZTA hip joint implants, and in one long-term retrieval study. We calculated the monoclinic content with the most used equations in the literature and compared it with the results of X-ray diffraction obtained on a similar probe depth. Our results show, contrary to many previous studies, that the long-term surface stability of ZTA ceramics is preserved. This suggests that the Raman technique does not offer consistent and unique results for the analysis of surface degradation. Moreover, we discuss here that tetragonal-to-monoclinic transformation is also necessary to limit contact damage and wear stripe extension. Thus, the surface metastability of zirconia-containing ceramics may be a non-issue.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100273
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 274: Flame Retardancy of Lightweight
           Sandwich Composites

    • Authors: Fabienne Samyn, Roland Adanmenou, Serge Bourbigot, Sophie Duquesne, Maude Jimenez, Marieke Van Marle, Sebastiaan Weij
      First page: 274
      Abstract: This study proposes an innovative solution to flame-retard a sandwich composite made of unsaturated polyester resin, glass fibre skins and polyester nonwoven core material. The strategy uses the core material as flame-retardant carrier, while the resin is also flame-retarded with aluminum trihydroxide (ATH). A screening of the fire-retardant performances of the core materials, covered with different types of phosphorous flame-retardant additives (phosphate, phosphinate, phosphonate), was performed using cone calorimetry. The best candidate was selected and evaluated in the sandwich panel. Great performances were obtained with ammonium polyphosphate (AP422) at 262 g/m2. The core material, when tested alone, did not ignite, and when used in the laminate, improved the fire behaviour by decreasing the peak of heat release rate (pHRR) and the total heat release (THR): the second peak in HRR observed for the references (full glass monolith and sandwich with the untreated core) was suppressed in this case. This improvement is attributed to the interaction occurring between the two FR additives, which leads to the formation of aluminophosphates, as shown using Electron Probe Micro-Analysis (EPMA), X-ray Diffraction (XRD) and solid-state 31P Nuclear Magnetic Resonance (NMR). The influence of the FR add-on on the core, as well as the ATH loading in the matrix, was studied separately to optimize the material performances in terms of smoke and heat release. The best compromise was obtained using AP422 at 182 g/m2 and 160 phr of ATH.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100274
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 275: Method for the Microstructural
           Characterisation of Unidirectional Composite Tapes

    • Authors: Nico Katuin, Daniël M. J. Peeters, Clemens A. Dransfeld
      First page: 275
      Abstract: The outstanding properties of carbon fibre-reinforced polymer composites are affected by the development of its microstructure during processing. This work presents a novel approach to identify microstructural features both along the tape thickness and through the thickness. Voronoi tessellation-based evaluation of the fibre volume content on cross-sectional micrographs, with consideration of the matrix boundary, is performed. The method is shown to be robust and is suitable to be automated. It has the potential to discriminate specific microstructural features and to relate them to processing behaviour removing the need for manufacturing trials.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100275
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 276: Triangular Functionally Graded Porous
           Moderately Thick Plates—Deformations and Free Vibrations

    • Authors: Aleksander Muc
      First page: 276
      Abstract: Since the finite element analysis of deformations for plates made of functionally graded materials cannot be carried out with the use of commercial FE packages, aconsistent method of analytical analysis is proposed in the paper. The method of the analysis is based on the application of the weighted residuals and the Bubnov–Galerkin method. The 2D formulation of moderately thick plates is adopted herein for classical and transverse shear deformation plate models (first and third order). Plate deformations subjected to uniform normalpressure and free vibrations are considered. The validity of the analytical model was verified by the comparison of results with FE analysis for isotropic plates. Two correction multipliers were proposed in order to take into account the unsymmetric composition of functionally graded porous plate walls.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100276
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 277: Using Graphene Nanoplatelets Nanofluid
           in a Closed-Loop Evacuated Tube Solar Collector—Energy and Exergy
           Analysis

    • Authors: Soudeh Iranmanesh, Mahyar Silakhori, Mohammad S. Naghavi, Bee C. Ang, Hwai C. Ong, Alireza Esmaeilzadeh
      First page: 277
      Abstract: Recently, nanofluid application as a heat transfer fluid for a closed-loop solar heat collector is receiving great attention among the scientific community due to better performance. The performance of solar systems can be assessed effectively with the exergy method. The present study deals with the thermodynamic performance of the second law analysis using graphene nanoplatelets nanofluids. Second law analysis is the main tool for explaining the exergy output of thermodynamic and energy systems. The performance of the closed-loop system in terms of energy and exergy was determined by analyzing the outcome of field tests in tropical weather conditions. Moreover, three parameters of entropy generation, pumping power and Bejan number were also determined. The flowrates of 0.5, 1 and 1.5 L/min and GNP mass percentage of 0.025, 0.5, 0.075 and 0.1 wt% were used for these tests. The results showed that in a flow rate of 1.5 L/min and a concentration of 0.1 wt%, exergy and thermal efficiencies were increased to about 85.5 and 90.7%, respectively. It also found that entropy generation reduced when increasing the nanofluid concentration. The Bejan number surges up when increasing the concentration, while this number decreases with the enhancement of the volumetric flow rate. The pumping power of the nanofluid-operated system for a 0.1 wt% particle concentration at 0.5 L/min indicated 5.8% more than when pure water was used as the heat transfer fluid. Finally, this investigation reveals the perfect conditions that operate closest to the reversible limit and helps the system make the best improvement.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100277
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 278: Calcium-Based Biomineralization: A
           Smart Approach for the Design of Novel Multifunctional Hybrid Materials

    • Authors: Elisabetta Campodoni, Margherita Montanari, Chiara Artusi, Giada Bassi, Franco Furlani, Monica Montesi, Silvia Panseri, Monica Sandri, Anna Tampieri
      First page: 278
      Abstract: Biomineralization consists of a complex cascade of phenomena generating hybrid nano-structured materials based on organic (e.g., polymer) and inorganic (e.g., hydroxyapatite) components. Biomineralization is a biomimetic process useful to produce highly biomimetic and biocompatible materials resembling natural hard tissues such as bones and teeth. In detail, biomimetic materials, composed of hydroxyapatite nanoparticles (HA) nucleated on an organic matrix, show extremely versatile chemical compositions and physical properties, which can be controlled to address specific challenges. Indeed, different parameters, including (i) the partial substitution of mimetic doping ions within the HA lattice, (ii) the use of different organic matrices, and (iii) the choice of cross-linking processes, can be finely tuned. In the present review, we mainly focused on calcium biomineralization. Besides regenerative medicine, these multifunctional materials have been largely exploited for other applications including 3D printable materials and in vitro three-dimensional (3D) models for cancer studies and for drug testing. Additionally, biomineralized multifunctional nano-particles can be involved in applications ranging from nanomedicine as fully bioresorbable drug delivery systems to the development of innovative and eco-sustainable UV physical filters for skin protection from solar radiations.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100278
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 279: Effect of Hybrid Fibres on the
           Durability Characteristics of Ternary Blend Geopolymer Concrete

    • Authors: V. Sathish Kumar, N. Ganesan, P. V. Indira
      First page: 279
      Abstract: The need to develop sustainable concrete in the civil infrastructure industry increases day by day, resulting in new eco-friendly materials such as geopolymer concrete. Geopolymer concrete is one of the eminent alternatives to conventional concrete for sustainable development by reducing the carbon footprint. Ternary blend geopolymer concrete (TGPC) is a sustainable and environmentally friendly concrete produced with three different source materials to form a binder. The main advantage of TGPC is that it possesses densely packed particles of different shapes and sizes, which results in improved properties. This paper deals with the experimental investigations to evaluate the durability properties of plain and hybrid fibre reinforced TGPC. The durability of concrete is defined as the ability to withstand a safe level of serviceability and different environmental exposure conditions without any significant repair and rehabilitation throughout the service life. Conventional concrete is vulnerable to cracking due to its low tensile and durability properties. The TGPC considered in this work consists of fly ash, GGBS and metakaolin as source materials, selected mainly based on the material’s silica and alumina content, shape, size, and availability. The grade of concrete considered was M55. The main variables considered in this study were the proportions of crimped steel fibres (Vf), viz., 0.5% and 1% and proportions of polypropylene fibres (Vp)viz., 0.1%, 0.15%, 0.20% and 0.25%. The durability properties like water absorption, sorptivity, resistance to marine attack, acid attack, sulphate attack, and abrasion were studied in this investigation. The experimental test results were compared with the requirements provided in the standard/literature and found to be well within limits. The study also indicates that the inclusion of fibres in a hybrid form significantly improves the durability parameters of TGPC. The TGPC with 1% steel fibre and 0.15% polypropylene fibre performs better than the other combination of fibres considered in this experimental investigation.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100279
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 280: Influence of Heat Treatment on the
           Corrosion Behaviour of Aluminium Silver Nano Particle/Calcium Carbonate
           Composite

    • Authors: Omolayo Michael Ikumapayi, Esther T. Akinlabi, Olayinka Oluwatosin Abegunde, Precious Ken-Ezihuo, Henry A. Benjamin, Sunday Adeniran Afolalu, Stephen A. Akinlabi
      First page: 280
      Abstract: Corrosion is one of the leading sources of material failure and deterioration in society. Scholars have proposed different techniques to mitigate corrosion. This research study explores and validates one of these techniques. An Aluminium metal matrix (AMC) was produced using the stir casting method with various weight percentages of AgNp and CaCO3 reinforcements. Heat treatment was performed on the samples to enhance the metallurgical and corrosion properties of the materials. The corrosion rate of the AMC samples was tested in different corrosive media (neutral and acidic) with different concentrations using the weight loss analysis technique for several days. It was observed that the corrosion rate of the AMC relies on the nature of the electrolyte and the percentage concentration of this electrolyte. The heat treatment improves the corrosion resistance of the AMC samples. In addition, an increase in the % weight composition of the reinforcement (AgNp + CaCO3) results in a reduction in the corrosion rate of the AMC in both corrosive media. The optimal %weight composition was found to be 4% for the hybrid reinforcement of AgNp + CaCO3 and 6% for the CaCO3 reinforcement in both the untreated and heat-treated samples.
      Citation: Journal of Composites Science
      PubDate: 2021-10-16
      DOI: 10.3390/jcs5100280
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 281: Mechanically Stable β-TCP Structural
           Hybrid Scaffolds for Potential Bone Replacement

    • Authors: Matthias Ahlhelm, Sergio H. Latorre, Hermann O. Mayr, Christiane Storch, Christian Freytag, David Werner, Eric Schwarzer-Fischer, Michael Seidenstücker
      First page: 281
      Abstract: The authors report on the manufacturing of mechanically stable β-tricalcium phosphate (β-TCP) structural hybrid scaffolds via the combination of additive manufacturing (CerAM VPP) and Freeze Foaming for engineering a potential bone replacement. In the first step, load bearing support structures were designed via FE simulation and 3D printed by CerAM VPP. In the second step, structures were foamed-in with a porous and degradable calcium phosphate (CaP) ceramic that mimics porous spongiosa. For this purpose, Fraunhofer IKTS used a process known as Freeze Foaming, which allows the foaming of any powdery material and the foaming-in into near-net-shape structures. Using a joint heat treatment, both structural components fused to form a structural hybrid. This bone construct had a 25-fold increased compressive strength compared to the pure CaP Freeze Foam and excellent biocompatibility with human osteoblastic MG-63 cells when compared to a bone grafting Curasan material for benchmark.
      Citation: Journal of Composites Science
      PubDate: 2021-10-17
      DOI: 10.3390/jcs5100281
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 282: Flexural Property of a Composite
           Biomaterial in Three Applications

    • Authors: Masao Irie, Yukinori Maruo, Goro Nishigawa, Takuya Matsumoto
      First page: 282
      Abstract: Resin composite is widely used in the dental field in clinics as a biomaterial. For example, it has been used as a composite material, a type of biomaterial, to repair caries and restore masticatory function, and as a luting agent to adhere the restoration to the tooth substrate. In order to demonstrate its function, we have measured the mechanical strength. From such basic research, we explain the potential of a dental material through the measurement of flexural strength and modulus of elasticity. In this research, we introduce commercial products that are actually used as composite materials suitable for tooth substrate and provide readers with their properties based on flexural strength and modulus of elasticity. In clinical performance, it might be advisable to delay polishing when a composite material is used for a luting material, a filling material and a core build-up material, as the flexural strength and the flexural modulus of elasticity were improved after 1 day of storage, and flexural strength and characteristics are considered as important mechanical properties of oral biomaterials.
      Citation: Journal of Composites Science
      PubDate: 2021-10-18
      DOI: 10.3390/jcs5100282
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 283: Recent Advances in Strain-Hardening
           UHPC with Synthetic Fibers

    • Authors: Jian-Guo Dai, Bo-Tao Huang, Surendra P. Shah
      First page: 283
      Abstract: This paper summarizes recent advances in strain-hardening ultra-high-performance concretes (UHPC) with synthetic fibers, with emphasis on their tensile properties. The composites described here usually contain about 2.0% high-density polyethylene (PE) fibers. Compared to UHPC with steel fibers, strain-hardening UHPC with synthetic fibers generally show a higher tensile ductility, lower modulus in the cracked state, and relatively lower compressive strength. The tensile strain capacity of strain-hardening UHPC with synthetic fibers increases with increasing tensile strength. The f’cftεt/w index (compressive strength × tensile strength × tensile strain capacity/tensile crack width) is used to compare the overall performance of strain-hardening UHPC. Moreover, a probabilistic approach is applied to model the crack width distributions of strain-hardening UHPC, and estimate the critical tensile strain in practical applications, given a specific crack width limit and cumulative probability. Recent development on strain-hardening UHPC with the use of seawater, sea-sand and PE fibers are also presented.
      Citation: Journal of Composites Science
      PubDate: 2021-10-18
      DOI: 10.3390/jcs5100283
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 284: The Factors That Affect the Expansion
           of the Tape for It to Avoid Side Effects in the Production of Composites
           in Online LATP Technology

    • Authors: Svetlana Risteska, Samoil Samak, Vele Samak
      First page: 284
      Abstract: During LATP (laser automated tape placement), the compaction roller contacts the prepreg and affects the pressure distribution directly. Moreover, the design parameters of the roller are optimized with the aim of improving pressure uniformity. This paper examines the impact of the contact line and surface that depends on the compaction force, the design of the roller, the angle of inclination and the angle of inclination of the strip. These factors significantly affect the expansion of the tape, and it is important to determine it to avoid side effects in the production of composites (formation of gaps or overlaps). Their presence increases the percentage of pores of the final material and thus reduces the mechanical properties. The results show that the pressure uniformity can be improved significantly by design optimization of the roller, which indicates that higher bond quality between layers is achieved. The lower the speed and higher the compact force in this technology give better intimate contact with a lower percentage of voids and good mechanical characteristics.
      Citation: Journal of Composites Science
      PubDate: 2021-10-19
      DOI: 10.3390/jcs5100284
      Issue No: Vol. 5, No. 10 (2021)
       
 
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