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  Subjects -> ENGINEERING (Total: 2312 journals)
    - CHEMICAL ENGINEERING (196 journals)
    - CIVIL ENGINEERING (192 journals)
    - ELECTRICAL ENGINEERING (104 journals)
    - ENGINEERING (1213 journals)
    - ENGINEERING MECHANICS AND MATERIALS (389 journals)
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    - MECHANICAL ENGINEERING (93 journals)

ENGINEERING (1213 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 254)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 6)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 27)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 10)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 30)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 2)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 6)
AIChE Journal     Hybrid Journal   (Followers: 32)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 17)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 8)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 18)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 1)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 6)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 24)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 30)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 2)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 271)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 199)
Composites Part B : Engineering     Hybrid Journal   (Followers: 256)
Composites Science and Technology     Hybrid Journal   (Followers: 194)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 7)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 5)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 33)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 43)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
Corrosion Series     Full-text available via subscription   (Followers: 6)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | Last

Journal Cover Composites Part B : Engineering
  [SJR: 2.125]   [H-I: 75]   [256 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1359-8368
   Published by Elsevier Homepage  [3123 journals]
  • Analytical solution for buckling of orthotropic double-layered graphene
           sheets exposed to unidirectional in-plane magnetic field with various
           boundary conditions
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): Nebojša Radić, Dejan Jeremić
      In this article, the analyses of the buckling behaviour of orthotropic double-layered graphene sheets (DLGSs), resting on Pasternak's elastic foundation with various boundary conditions and subjected to unidirectional in-plane magnetic field are presented. The governing equations of equilibrium of the nonlocal model are derived in terms of generalized displacement using the new first-order shear deformation theory (NFSDT) and Maxwell's equations in conjunction with the Eringen's differential nonlocal elastic law. An explicit solution for buckling loads is obtained for orthotropic DLGSs under biaxial and uniaxial loads. The effectiveness of the present formulation and solutions are firstly validated by executing the comparison studies with results available in the literature. The effects of nonlocal parameter, magnetic field strength, a different type of load and boundary conditions, aspect ratio, side length and number of half waves on the buckling behaviour of DLGSs are investigated.

      PubDate: 2018-02-05T07:21:14Z
       
  • Modeling the effective mechanical properties of “fuzzy fiber”
           composites across scales length
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): S.A. Lurie, D.B. Volkov-Bogorodskiy, O. Menshykov, Y.О. Solyаev, E.С. Aifantis
      We employ a variant of generalized Eshelby's homogenization method to deduce effective properties of multilayered nanostructured fiber composites where one layer is highly heterogeneous with respect to its mechanical response strain gradients. We focus on carbon (C) fibers coated by carbon nanotubes (CNT) embedded in polymeric matrix with the aid of CNT “blistered” interphase layer developed between the coating and the matrix during processing and/or use. Each of the three phases is treated for simplicity by classical elasticity, while the interphase layer around the coated fibers (“fuzzy fibers”) to provide adhesion, and is treated by the simple gradient elasticity (GradELa) model. The novelty of the work lies on the fact of treating the CNT “fuzzy” layer by the GradEla model, that consequently allows to consider the extra gradient coefficient or internal length (characterizing this model) in relation to other constitutive and geometric parameters of the composite to optimize its overall mechanical properties and functionality. The method is general and can apply to treat other types of “fuzzy fiber” composites.

      PubDate: 2018-02-05T07:21:14Z
       
  • Mechanical characterization of pultruded elements: Fiber orientation
           influence vs web-flange junction local problem. Experimental and numerical
           tests
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): Attilio Quadrino, Rosa Penna, Luciano Feo, Nicola Nisticò
      Fiber Reinforced Polymers (FRP) material are proposed and implemented for civil engineering applications for both retrofitting of existing structures and building of new facilities. In new construction realizations, FRP elements are frequently manufactured using pultrusion that represents a high rate manufacturing method, however characterized by a prevalent longitudinal fiber orientation with consequently weakness along the directions different than the longitudinal one. The intrinsic orthotropy, the presence of defects due to the manufacturing processes and the brittle failure mechanisms are peculiarities that decelerate their wide applications, so that are an open issue to be solved. In this regard, the present work experimentally investigates the local behavior of a commercial Pultruded I-shaped Glass FRP (PGFRP) element, in order to: 1) evaluate the mechanical properties of the material according to different fiber orientations, 2) check the validity of the Tsai Hill Criterion and 3) investigate the capacity of the web-flange (WF) junction, that is a recognized weak point, through a novel and simple experimental test.

      PubDate: 2018-02-05T07:21:14Z
       
  • Analytical model of the dynamic behaviour of CFRP plates subjected to
           low-velocity impacts
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): M. Salvetti, A. Gilioli, C. Sbarufatti, A. Manes, M. Giglio
      In the light of an increment of the safety of CFRP components and systems subjected to low-velocity impacts, the identification of a damage onset threshold is desired. Hence the suitability of an analytical model for the estimation of the critical load of delamination onset, as well as, an approximation of the load-displacement curve, has been investigated. Starting from the Olsson's analytical model, available in the literature, a new model has been developed for the prediction of the mechanical behaviour of composite laminates subjected to low-velocity impacts, following a dynamic approach and taking into account stiffness degradation. The performances of the new model have been compared with results of an experimental impact testing program, showing good agreement with the data and significant improvements when compared with the Olsson's model.

      PubDate: 2018-02-05T07:21:14Z
       
  • An iterative analytical model for heterogeneous materials homogenization
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): D. Batache, T. Kanit, W. Kaddouri, R. Bensaada, A. Imad, T. Outtas
      The purpose of this study was to establish a method based on an iterative scheme to approximate the numerical solution obtained from finite elements analysis for an RVE in two and three dimensions based on the homogenization concept for the assessment of the effective properties. The bounds of Hashin–Shtrikman and Voigt–Reuss were considered in the iterative process based on an updating of the constitutive relations of these models respectively. In this study, by assumption, we took the particular case of the heterogeneous materials with several elastic isotopic phases. The output variables considered using the iterative process are the bulk, shear modulus and the thermal conductivity. We have found a fast convergence of the iterative solution to the numerical result with a suitable concordance between the two solutions at the final step.

      PubDate: 2018-02-05T07:21:14Z
       
  • On the influence of structural defects for honeycomb structure
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): Zhonggang Wang, Zhendong Li, Wei Zhou, David Hui
      Defect in honeycomb has been paid close attention in recent years, as it significantly threats on its performance. In this study, detailed behavior and influence were extensively investigated in terms of defect distribution, influence on the mechanical performance, as well as the improvement methodology. Firstly, quasi-static experiments were extensively conducted to directly evaluate the inhomogeneity with 12 sub-blokes divided from a given conventional man-made honeycomb core. Variances in the resultant compression history as well as strength of these sub-blocks were determined. From the experimental observation, it can be seen that the regularity and adhesive failure of cells happened in expansion process are two main reasons for strength inhomogeneity. Afterwards, parametric studies on the extensive influence on mechanical performance were discussed by employing the specimens with structural defects in terms of the irregularity, under and over stretch states and adhesive failure. As the findings cofirmed that, the structural defects hugely cut down the plateau force and energy absorption capacity. The honeycomb with regular hexagonal cells without any adhesive failure performs the best. To improve the irregularity, a Machine Vision Methodology was put forward for cells expansion supervision. Detail algorithm in vertex identifying of honeycomb cell was discussed. All these achievements shed a light on the consistency, reliability and homogeneity of high standard honeycomb structure.

      PubDate: 2018-02-05T07:21:14Z
       
  • Nanoscaled superelastic behavior of shape memory alloy/metallic glass
           multilayered films
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): W.T. Jhou, C. Wang, S. Ii, C.H. Hsueh
      The mechanical properties of multilayered films with alternate layers of shape memory alloy (SMA) and metallic glass (MG) were studied. Specifically, TiNi SMA and ZrCuAlNi MG were deposited alternately on the Si substrate using magnetron sputtering. The as-deposited multilayered film was amorphous. The annealing temperature was chosen judiciously to crystalize TiNi layer while ZrCuAlNi layer remained amorphous. The superelastic behavior of SMA/MG multilayered film was characterized using nanoindentation tests. The stress required to induce martensitic transformation of TiNi layer increased as the thickness of TiNi layer decreased. Also, the multilayered SMA/MG films were found to have the better deformation recovery after indentation unloading which could be due to the synergy effects of superelasticity from SMA layers and high elastic strain limit from MG layers.

      PubDate: 2018-02-05T07:21:14Z
       
  • Graphene-based materials and their composites: A review on production,
           applications and product limitations
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): Velram Balaji Mohan, Kin-tak Lau, David Hui, Debes Bhattacharyya
      Recent years have perceived many innovations in research and advancement of graphene, the thinnest two-dimensional atomic material. Graphene-based materials and their composites possess promising applications in wide range of fields such as, electronics, biomedical aids, membranes, flexible wearable sensors and actuators. The latest studies and progression in this subject area often produce inconsistent or inconclusive results. This review article assesses and summarises published data so as to provide a critical and comprehensive overview of state of the art. Firstly, the distinct structural nature of the graphene materials available is elucidated, as well as different production techniques available thus far. The assessment then discusses the various composites focusing different sub-functional regimes such as mechanical and collective functional applications such as energy, electronics biomedical, membranes and sensors. The utilisation of graphene and its derivatives in the manufacture of nanocomposites with different polymer matrices has been reconnoitred. Finally, a conclusion and perspective are given to discussing the remaining challenges for graphene nanocomposites in functional science and engineering.

      PubDate: 2018-02-05T07:21:14Z
       
  • Review of current trends in research and applications of sandwich
           structures
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): Victor Birman, George A. Kardomateas
      The review outlines modern trends in theoretical developments, novel designs and modern applications of sandwich structures. The most recent work published at the time of writing of this review is considered, older sources are listed only on as-needed basis. The review begins with the discussion on the analytical models and methods of analysis of sandwich structures as well as representative problems utilizing or comparing these models. Novel designs of sandwich structures is further elucidated concentrating on miscellaneous cores, introduction of nanotubes and smart materials in the elements of a sandwich structure as well as using functionally graded designs. Examples of problems experienced by developers and designers of sandwich structures, including typical damage, response under miscellaneous loads, environmental effects and fire are considered. Sample applications of sandwich structures included in the review concentrate on aerospace, civil and marine engineering, electronics and biomedical areas. Finally, the authors suggest a list of areas where they envision a pressing need in further research.

      PubDate: 2018-02-05T07:21:14Z
       
  • Recent advances in carbon-fiber-reinforced thermoplastic composites: A
           review
    • Abstract: Publication date: 1 June 2018
      Source:Composites Part B: Engineering, Volume 142
      Author(s): Shan-Shan Yao, Fan-Long Jin, Kyong Yop Rhee, David Hui, Soo-Jin Park
      Carbon fibers (CFs) have high specific tensile strength, high modulus, and outstanding wear resistance, and are widely used for the reinforcement of advanced composite materials. CF-reinforced thermoplastic composites have received much attention because of their easy processability and recycling convenience compared with thermosetting composites. Surface treatment of CFs is generally employed to increase the surface functional groups and interfacial adhesion between the CFs and the surrounding polymer matrix. In this review, we explore recent advances in the surface treatment of CFs and preparation of CF/thermoplastic composites. The thermal, mechanical, and electrical properties of the composites are also discussed.

      PubDate: 2018-02-05T07:21:14Z
       
  • Towards selection chart of flame retardants for natural fibre reinforced
           polypropylene composites
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): A. Elsabbagh, T. Attia, A. Ramzy, L. Steuernagel, G. Ziegmann
      The market of natural fibre thermoplastic composites NFTC is still developing. However, it is limited by the progress in optimising the process parameters and defining the functional additives. One of the most needed additives is the flame retardant FR material. Addition of excessive FRs can decrease the mechanical properties. Polypropylene PP reinforced with 30% natural fibres (flax, jute, hemp and sisal) are prepared using kneading and different FRs are mixed together. The effect of the different FRs on the flame retardance level, namely UL94, as well as the mechanical properties are studied. The studied FRs materials in this work are mineral, halogenated, halogen-free intumescent. Also, the effect of synergism with nanoclays and antimony trioxide is considered. Based on the mechanical properties and the flame retardance levels, a concept of FR selection chart is built considering only the both aspects of the tensile strength and flame retardance test UL94.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • Longitudinal compression and Poisson ratio of fiber yarns in meso-scale
           finite element modeling of composite reinforcements
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): D. Wang, N. Naouar, E. Vidal-Salle, P. Boisse
      Meso-scale finite element modeling is a powerful tool to analyze the deformation of textile composite reinforcements. At the meso-scale, the yarns of the reinforcement are considered to be solids made of a continuous material in contact with their neighbors. These yarns are generally under tension, but some loadings of the reinforcement lead to a longitudinal compression state. The yarns, made up of a large number of fibers, present a specific behavior when under longitudinal compression. Local buckling of the fibers causes the compressive stiffness of the continuous material representing the yarn to be much weaker than when under tension. In addition, longitudinal compression causes an important transverse expansion. It is shown in the present work that the transverse expansion could be depicted by a Poisson ratio that remained roughly constant when the yarn length and the compression strain varied. Buckling of the fibers significantly increases the transverse dimensions of the yarn which leads to a large Poisson ratio (up to 12 for a yarn analyzed in the present study). The longitudinal compression and transverse expansion were integrated in a mechanical model of the yarn. Meso-scale finite element simulations of reinforcements with binder yarns submitted to longitudinal compression showed that these improvements led to results in good agreement with micro-CT analyses.

      PubDate: 2018-02-05T07:21:14Z
       
  • Full-scale tests on masonry vaults strengthened with Steel Reinforced
           Grout
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Stefano De Santis, Francesca Roscini, Gianmarco de Felice
      Masonry vaults can be particularly vulnerable against unsymmetrical service loads, support displacements and seismic actions. Retrofitting is often needed to ensure an adequate safety level according to current standard codes. Externally bonded composites are emerging as a possible retrofitting technique, but no experimental evidence is still available on the response of reinforced vaults taking into account the contribution of buttresses and backfill. This paper describes an experimental investigation on four full-scale vault specimens. One of them was tested unreinforced, whereas the other ones were strengthened with Steel Reinforced Grout (SRG), comprising ultra high tensile strength steel cords, bonded with lime-based mortar either to the extrados or to the intrados. The vaults were subjected to cyclic loading at 1/3 span. The backfill was visible through a panel of Plexiglas, allowing for the use of Digital Image Correlation to measure the displacement field and derive information on damage pattern and arch-fill interaction. Tests showed that SRG prevented the development of the four-hinge mechanism and avoided damage concentrations, increasing the deflection capacity and the strength of the arch by 2–3 times. Finally, it is shown that a simplified analytical approach based on limit analysis provides a reliable estimate of experimental load carrying capacity.

      PubDate: 2018-02-05T07:21:14Z
       
  • Fatigue behaviour at elevated temperature of RC slabs strengthened with EB
           CFRP strips
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Juan Manuel Gallego, Christoph Czaderski, Matteo Breveglieri, Julien Michels
      Reinforced concrete (RC) structures such as concrete box-girder highway bridges may suffer fatigue damage due to cyclic loads. Externally bonded (EB) carbon fibre reinforced polymer (CFRP) strips can be used to increase the fatigue (and static) load bearing capacity of such elements and to increase the service life of the elements. The EB CFRP strips under the asphalt layer can reach elevated temperatures of up to 50 °C during summer when the asphalt is directly exposed to solar radiation. Therefore, in this study, the fatigue behaviour at an elevated temperature of RC slabs strengthened with EB CFRP strips is evaluated. The focus is on the strengthening of lateral cantilevers of deck slabs of concrete box-girder highway bridges. The fatigue behaviour of RC elements is a complex phenomenon that is influenced by many parameters such as the maximum load, stress oscillation level on the longitudinal steel reinforcement, shear span-to-depth ratio, and quality of concrete. This phenomenon becomes even more complicated when elevated temperatures are considered. Majority of the existing experimental works on fatigue behaviour of EB-strengthened RC structures showed that the typical fatigue failure at room temperature is caused by fatigue failure of the longitudinal steel reinforcement followed by strip debonding. In this study, it was investigated if a different type of failure can be observed at elevated temperatures owing to the changes in epoxy properties.

      PubDate: 2018-02-05T07:21:14Z
       
  • A multiscale damage analysis of periodic composites using a
           
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Lorenzo Leonetti, Fabrizio Greco, Patrizia Trovalusci, Raimondo Luciano, Renato Masiani
      A novel multiscale strategy is proposed for the damage analysis of masonry structures modeled as periodic composites. Such a computational strategy, whose aim is to reduce the typically high computational cost exhibited by fully microscopic numerical analyses, is based on a multiscale/multidomain model equipped with an adaptive capability, which allows to automatically zoom-in the zones incipiently affected by damage onset. The associated model refinement criterion requires the determination of microscopically informed first failure surfaces, which take into account both classical and bending deformation effects, by taking advantage of a couple-stress based homogenization technique. In order to assess the efficacy of the proposed multiscale modeling strategy, some numerical simulations are presented, involving a medium-sized wall test subjected to combined shear and flexure loading conditions. The related accuracy and computational performances of this methodology are investigated via suitable comparisons with a purely discrete model of masonry. Special attention is devoted to the analysis of the bending macroscopic deformation effects. Further comparisons with experimental results taken from the literature are carried out in order to validate its predictive capability in terms of peak and post-peak mechanical behavior.

      PubDate: 2018-02-05T07:21:14Z
       
  • Design models for circular and square RC columns confined with GFRP sheets
           under axial compression
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Mariana Jesus, Paulo Silva Lobo, Pedro Faustino
      The confinement of reinforced concrete structural elements can significantly increase their strength and ductility. This motivated numerous research works using different materials, among which are composites. A significant number of constitutive models developed to predict the behaviour of columns confined with fiber polymer sheets have been proposed. Nonetheless, the existing design-oriented models were mainly calibrated for carbon fiber based materials. In the research presented in this paper, sixty experimental results of concrete columns confined with glass fiber reinforced polymers under quasi-static monotonic loading were analysed. This made it possible to calibrate the parameters of a design-oriented model for the prediction of the response of confined concrete columns, with both circular and square cross-sections. The comparison of the proposed model and of an analysis-oriented model with experimental results is presented. The results of the former model show good correlation with experimental data and are generally more accurate than those of the analysis-oriented model considered.

      PubDate: 2018-02-05T07:21:14Z
       
  • Silk fibroin-magnetic hybrid composite electrospun fibers for tissue
           engineering applications
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): R. Brito-Pereira, D.M. Correia, C. Ribeiro, A. Francesko, I. Etxebarria, L. Pérez-Álvarez, J.L. Vilas, P. Martins, S. Lanceros-Mendez
      This manuscript reports on the fabrication of silk fibroin (SF)-based magnetic electrospun fiber composites as scaffolds for tissue engineering applications. The magnetic responsiveness of the SF composite fibers was achieved by the inclusion of cobalt ferrite (CoFe2O4) or magnetite (Fe3O4) nanoparticles prior to processing the fibers via electrospinning. The influence of the processing parameters, including type and amount of nanoparticles in the composite, on the mean fiber size and size distribution was studied. Whereas the average diameter of pristine SF fibers was of 294 ± 53 nm, the inclusion of 5% of CoFe2O4 and Fe3O4 nanoparticles led to a slight increase in the fiber diameter. Nevertheless, the fiber diameter decreased with the higher nanoparticles loading. Regarding the physico-chemical properties of the fibrous mats, it was observed that the degree of crystallinity dropped from 67% of the pristine SF mats to 37% for the SF composites. On the other hand, the onset degradation temperature of the SF electrospun was not significantly altered by inclusion of ferrite nanoparticles. It is shown that the magnetization saturation increased with the nanoparticle filler content for both compositions (CoFe2O4/SF and Fe3O4/SF). Neither the SF pristine fibers nor the SF composites were cytotoxic, indicating their suitability for tissue engineering applications.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • On the mechanical properties of monolithic and laminated nano-ceramic
           resin structures obtained by laser printing
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): B. Henriques, P. Pinto, F.S. Silva, M.C. Fredel, D. Fabris, J.C.M. Souza, O. Carvalho
      The purpose of this study was to evaluate the mechanical properties of laser printed monolithic and laminated nano ceramic resins (NCR) for dental prosthetic applications. Three different types of discs were produced by laser printing: monolithic NCR discs and laminated NCR discs with 100 μm (laminate_100) and 500 μm (laminate_500) resin interlayers (n = 10). To assess the adhesion strength of the photosensitive resin used as interlayer to the NCR, cylindrical specimens were produced. The biaxial flexural strength and shear bond strength of the specimens were measured using a universal testing machine. Data was statistically analyzed by one-way ANOVA followed by Tukey HSD test (α = 0.05). The microstructure and fracture surfaces were analyzed by SEM/EDS. Results were rationalized with finite element analysis (FEA). Laminate_100 specimens showed significantly higher flexural strength (∼50%) than monolithic and Laminate_500 specimens (p < .05). A good adhesion between the resin used as interlayer and the NCR was registered. FEA revealed a more favorable stress distribution in laminates with a thinner interlayer. Modern CAD/CAM systems can be used in the direct manufacturing of correctly designed laminated structures displaying enhanced strength and damage tolerance relative to conventional monolithic ones, thereby positively impacting their clinical performance.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • Analytical model for predicting the tensile strength of unidirectional
           composites based on the density of fiber breaks
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): J.D. Vanegas-Jaramillo, A. Turon, J. Costa, L.J. Cruz, J.A. Mayugo
      While analytical fiber fragmentation models following the global load-sharing (GLS) assumption efficiently reproduce the stress strain curves of unidirectional composites loaded in the direction of the reinforcement when the number of breaks is moderate, they completely fail to predict tensile strength. In this paper, we propose that failure takes place when a critical density of breaks, which depends entirely on the constituent properties, is reached. Therefore, we rewrite classic GLS fragmentation models in terms of the linear density of breaks. The critical number of breaks for a set of glass and carbon reinforced polymer composites is extracted from published experimental data and fitted to an empirical law, with good predictive capability. Our approach complements GLS fragmentation models because it identifies the ultimate stress, from which the stress-strain curve given by the model becomes unrealistic.

      PubDate: 2018-02-05T07:21:14Z
       
  • Effect of filler particle shape on plastic-elastic mechanical behavior of
           high density poly(ethylene)/mica and poly(ethylene)/wollastonite
           composites
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Lubomír Lapčík, David Maňas, Barbora Lapčíková, Martin Vašina, Michal Staněk, Klára Čépe, Jakub Vlček, Kristian E. Waters, Richard W. Greenwood, Neil A. Rowson
      It was found in this study that both fillers (mica and wollastonite) trigger an increase in Young's modulus of elasticity with increasing filler concentration in a HDPE composites matrix. In the case of HDPE/mica the same improvement was also found for the upper yield point vs. filler concentration dependencies indicating higher stiffness. However, for the HDPE/wollastonite composites the opposite trend was observed, i.e. a decrease of the upper yield point and strain at break. These findings were also confirmed by mechanical vibration damping testing where there was found a more intense shift of the first resonance frequency peak position to higher frequencies with increasing filler concentrations for HDPE/mica in comparison to HDPE/wollastonite composites. Both composites exhibited decreasing strain at break with increasing filler concentration indicating a more brittle mechanical behavior in comparison to the virgin HDPE polymer matrix. However, for HDPE/wollastonite composites at 5 w. % filler concentration a 15% increase in the magnitude of the strain at break was found indicating an increase in ductility at 50 mm/min deformation rate. Fracture toughness measurements show, that both studied fillers function as the stress concentrators in the HDPE polymer matrix, which was reflected in the exponentially decreasing dependencies of the fracture toughness vs. filler concentrations. SEM analysis of the fracture surfaces show typical elongation bands of high plasticity deformation regions characteristic of typical shearing bands, interpenetrated with cavities created around filler particles. Thermal analysis data showed for HDPE/mica a strong increase of the crystallinity with increasing filler concentration, however in the case of HDPE/wollastonite the opposite effect of a higher amorphous polymer phase content was found.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • Viscoelastic modelling and dynamic characteristics of CNTs-CFRP-2DWF
           composite shell structures
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Ashirbad Swain, Tarapada Roy
      The carbon nanotubes (CNTs) are well known for its application in the areas of advanced composite materials for their improved elastic properties. The large specific interfacial surface area owing to tiny dimensions of CNTs may greatly escalation the interfacial sliding which may promote the dissipation of energy in a dynamic situation that makes them very ideal for damping applications in engineering structures/systems. The present article investigates the viscoelastic modelling and dynamic responses of the CNTs – based carbon fiber reinforced two dimensional woven fabrics (CNTs-CFRP-2DWF) composite spherical shell panels where CNTs are reinforced in the polymer matrix phase. The Mori – Tanaka (MT) micromechanics in conjunction with weak interface (WI) theory has been developed for the mathematical formulations of the viscoelastic modelling of CNTs-based polymer matrix phase. Further, strength of material (SOM) method has been employed to formulate viscoelastic material behavior of the yarn and finally the viscoelastic properties of the representative unit cell (RUC) is established based on the unit cell method (UCM). An eight-node shell element with five degree of freedom per node has been formulated to study the vibration damping characteristics of spherical shell structures made by CNTs-CFRP-2DWF composite materials. The shell finite element formulation is based on the transverse shear effect as per the Mindlin's hypothesis, and stress resultant-type Koiter's shell theory. Frequency and temperature dependent material properties of such CNTs-CFRP-2DWF composite materials have been obtained and analysed. Impulse and frequency responses of such structures have been performed to study the effects of various important parameters such as volume fraction of CNTs, interfacial condition, agglomeration, temperature, geometries of shell panel on the material properties and such dynamic responses. Obtained results demonstrate that quick vibration mitigation may be possible using such CNTs-CFRP-2DWF composite material which is desirable to overcome the drawbacks of conventional CFRP woven fabric composite materials.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • Effect of the environment on the performance of GFRP reinforcing bars
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): T. D'Antino, M.A. Pisani, C. Poggi
      Fiber reinforced Polymer (FRP) composites are currently employed in the civil engineering industry as externally bonded reinforcement (EBR) of existing reinforced concrete (RC) and masonry structures and as internal reinforcement of concrete elements as an alternative to steel reinforcing bars. Carbon FRP (CFRP) composites are mainly used for EBR applications whereas glass FRP (GFRP) bars are employed as internal reinforcement of concrete elements. This paper sheds light into the effect of different aggressive environments on the tensile behavior of reinforcing GFRP bars. 356 results of tensile tests of GFRP bars subjected to hot dry and humid air, different alkali environments, salt solutions with various concentrations, and plain and distillated water were collected from the literature. According to the “design by testing” procedure provided by EN 1990, a statistical analysis of the results was carried out to calibrate environmental reduction factors able to provide reliable estimations of the long-term behavior of GFRP bars subjected to different exposure conditions. For a given aggressive environment, a clear and unique degradation trend could not be identified, which points out the need of a standard testing procedure able to provide reliable and repeatable results.

      PubDate: 2018-02-05T07:21:14Z
       
  • Curvilinear GFRP bars for tunnel segments applications
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Simone Spagnuolo, Alberto Meda, Zila Rinaldi, Antonio Nanni
      The possibility of adopting glass-fiber reinforced polymer (GFRP) composite bars in tunnel segments as a substitute of the traditional steel reinforcement has been demonstrated. Nevertheless, this application requires a curvilinear shape for the reinforcement, and thus a different production process and rebar geometry. The aim of the paper is the experimental evaluation of the physical and mechanical properties of non-conventional GFRP rebars. The test procedures and obtained results are highlighted and compared with the acceptance criteria available for straight pultruded rebars. Finally, the presented outcomes show the suitability of GFRP non-conventional bars as reinforcement for precast concrete segments in tunnel applications.

      PubDate: 2018-02-05T07:21:14Z
       
  • Nonlinear bending analysis of FG-GRC laminated cylindrical panels on
           elastic foundations in thermal environments
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Hui-Shen Shen, Y. Xiang, Yin Fan, D. Hui
      This paper presents an investigation on the nonlinear bending behaviors of nanocomposite laminated cylindrical panels made of graphene-reinforced composites (GRCs) supported by an elastic foundation under thermal environmental conditions. The extended Halpin-Tsai micromechanical model together with results from MD simulations is employed to obtain the material properties of GRCs which are temperature dependent. A piece-wise functionally graded distribution of graphene fillers along the panel thickness direction is adopted in order to maximize the effect of graphene reinforcement to the panels. The Reddy's third order shear deformable shell theory is applied to derive the governing equations for the bending problem of the panels and the von Kármán geometric nonlinearity, the foundation support and the temperature effect are also included in the derivation. The governing equations are solved by applying a two-step perturbation approach to obtain the panel load-deflection and load-bending moment curves of FG-GRC laminated cylindrical panels subjected to a transverse uniform or sinusoidal load. The influences of loading conditions and temperature variation on the nonlinear bending behaviors of FG-GRC laminated cylindrical panels are discussed in details.

      PubDate: 2018-02-05T07:21:14Z
       
  • Combined centrifugal-slip casting method used for preparation the Al2O3-Ni
           functionally graded composites
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Justyna Zygmuntowicz, Aleksandra Miazga, Paulina Wiecinska, Waldemar Kaszuwara, Katarzyna Konopka, Mikolaj Szafran
      The centrifugal-slip casting method was used for producing the Al2O3-Ni composites with a gradient distribution of the Ni phase. The final products had the shape of hollow cylinders. The casting slurries were water-based and contained alumina and nickel powders with two different particle sizes. The cast samples were then subjected to sintering at a temperature of 1400 °C in an N2/H2 reducing atmosphere with heating and cooling rates of 1 °C/min, and the dwell time - 4 h. The rheological properties of the water-based slurries were examined. It appeared that the presence of the Ni particles strongly affected the slurry properties which was probably associated with the strong interactions between the Ni and α-Al2O3 particles. The Al2O3-Ni composites with a gradient distribution of the Ni particles were examined using the X-ray diffraction method. No new phases such as the nickel aluminate spinel were identified in the sintered composites. The microstructure of the samples was analyzed using Scanning Electron Microscopy (SEM). The observations revealed that the samples were composed of three zones with different distributions of the Ni particles on their cross-section. Finally, the Ni particle distribution in the functionally graded materials was described quantitatively.

      PubDate: 2018-02-05T07:21:14Z
       
  • Strain rate dependent multiaxial characterization of long fiber reinforced
           plastic
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): J. Lienhard, L. Schulenberg
      Long-fiber reinforced thermoplastics (LFT) were characterized for automotive applications with high rate experiments in a range of strain rate from 10 − 3 s − 1 up to 10 2 s − 1 . High-speed video imaging with digital image correlation (DIC) and a high-speed infra-red camera are applied to investigate the strain and temperature development during four different testing types. Different states of stress were investigated to provide adequate input data for simulation. A new fracture initiation criterion is introduced. Nearly pure shear load could be reached with a specifically designed specimen. It was found that global deformations rise with the strain rate, while local strains decrease. The adiabatic temperature-rise enlarges the deformation zone, impedes strain localization and leads to higher energy absorption at higher strain rates.

      PubDate: 2018-02-05T07:21:14Z
       
  • Effect of ageing on the mechanical and chemical properties of binder from
           RAP treated with bio-based rejuvenators
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): M.C. Cavalli, M. Zaumanis, E. Mazza, M.N. Partl, L.D. Poulikakos
      Reclaimed asphalt pavement (RAP) is harder than virgin bitumen due to ageing and it needs to be rejuvenated. Three bio-based rejuvenators are used and the rejuvenating effects are evaluated. Rheological tests show how the rejuvenators may restore the mechanical properties of RAP binder. An ageing index is proposed to show that the rejuvenators are affected differently by ageing. Despite their addition, physio-chemical oxidation did not reverse. Mechanical changes were not caused by chemical changes at functional groups level but a rearrangement of polar/nonpolar components. The results show that considering the effect of aging is vital in identifying how rejuvenators affect the RAP binder chemically and mechanically.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • Effect of perlite particle contents on delamination toughness of S-glass
           fiber reinforced epoxy matrix composites
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Mohamad Alsaadi, Ahmet Erkliğ
      The effects of perlite particulate-filler on the mode I and mode II interlaminar fracture and mechanical behavior of glass fabric/epoxy composites were studied. Composite specimens for double-cantilever beam (DCB), end-notched flexure (ENF) tensile and flexural tests were prepared and tested according to ASTM standards with perlite contents of 1, 3, 5 and 10 wt%. The optical and scanning electron microscopes images were described the mechanisms of mode I and II interlaminar fracture. The results indicated that the mode I and mode II interlaminar fracture toughness were optimum at perlite content of 3 wt% with increment of 39.9% and 72.3%, respectively. The tensile strength and flexural properties reached maximum values at perlite content of 1 and 5 wt%, respectively.

      PubDate: 2018-02-05T07:21:14Z
       
  • Silica coating for interphase bond enhancement of carbon and AR-glass
           Textile Reinforced Mortar (TRM)
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): C. Signorini, A. Nobili, E.I. Cedillo González, C. Siligardi
      In this paper, we investigate the effect of silica nano-coating for interphase bond enhancement on the mechanical performance of Textile Reinforced Mortar (TRM) composite materials aimed at structural rehabilitation and strengthening. Alkali-resistant glass (ARG) and carbon fabric reinforcements are preliminarily treated via sol-gel deposition of SiO2 coating to promote bond formation capability with the mortar matrix. Optical and electron microscopy provide evidence of interphase bond enhancement. Mechanical performance is assessed both in traction, through uni-axial elongation of prismatic coupons, and in flexure, by three-point bending of laminated masonry bricks. Results are given in terms of mean strength curves, ultimate and design strength and strain values, cracked and uncracked moduli, mean crack spacing, mean crack width and energy dissipation. It is shown that mean absolute performance of silica coating offers a significant improvement over uncoated fabric, yet it is inferior to that of specimens which have been treated with a liquid partially-organic adhesion promoter (polymer coating). However, when design values are considered which incorporate the dispersion of experimental data, silica coating proves superior or at least equivalent to polymer coating, respectively for carbon and ARG fabric. These promising results describe the first application of silica nano-coating to fabric reinforced composite materials.

      PubDate: 2018-02-05T07:21:14Z
       
  • Microstructures and mechanical properties of Cu/Ti3SiC2/C/graphene
           nanocomposites prepared by vacuum hot-pressing sintering and hot isostatic
           pressing
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Xiaosong Jiang, Wanxia Liu, Yanjun Li, Zhenyi Shao, Zhiping Luo, Degui Zhu, Minhao Zhu
      Copper-graphite composite is an ideal friction material due to its good heat resistance, wear resistance and friction coefficient stability. The addition of Ti3SiC2 can improve strength, hardness and wear resistance of copper-graphite alloy material without affecting its self-lubricating properties and electrical conductivity. Two-dimensional graphene has become an attractive composite reinforcement owing to their unique electrical, mechanical and thermal properties. Cu/Ti3SiC2/C/Graphene naocomposite materials reinforced with graphene have been fabricated by vacuum hot-pressing sintering and hot isostatic pressing. Microstructures and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials with different graphene contents have been systematically investigated. Microstructures of the composites were examined by optical microscopy, X-ray diffraction, back scattered electron imaging, scanning electron microscope with energy dispersive spectrometer and transmission electron microscope. The mechanical properties were determined from Brinell hardness, tensile, compressive and shear tests. Results demonstrated that there was an optimum value of graphene content which has an impact on microstructures and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials. Based on graphene content on microstructure and mechanical properties of Cu/Ti3SiC2/C/Graphene naocomposite materials, strengthening and fracture mechanisms by graphene reinforcement have been analyzed.

      PubDate: 2018-02-05T07:21:14Z
       
  • Ultra-low sintering temperature ceramic composites of CuMoO4 through Ag2O
           addition for microwave applications
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): Nina Joseph, Jobin Varghese, Merja Teirikangas, Mailadil Thomas Sebastian, Heli Jantunen
      The present paper presents ceramic composites with ultralow sintering temperature of 500 °C and densification of 96% by adding small amount (0.5, 1 and 2 wt%) of Ag2O to CuMoO4 by simple mixing method. The effect of Ag2O addition on the structure, microstructure, sintering and thermal as well as microwave dielectric properties of CuMoO4 is also studied. The reduction in the sintering temperature is due to the formation of trace amount (1.4%) of copper silver molybdate (Cu2Ag2(MoO4)3) as observed from Rietveld refinement analysis as well as backscattered SEM image. Doping has very little influence on the structure and coefficient of thermal expansion that is about 4.7–5.2 ppm/°C. The composites sintered at 500 °C exhibit relative permittivity of about 8–9, quality factor (Qf) of 26000–37000 GHz at 12 GHz, temperature coefficient of resonant frequency of -31-33 ppm/°C and are compatible with Al electrode. The present work results in obtaining well-densified ultralow temperature cofired ceramic composites at low sintering temperature without much structural change and good thermal properties but with different dielectric properties by small doping. These composites can be used as low cost candidates for wide range of microwave applications like multilayer packages and substrates owing to the low energy required during processing and hence can pave way to the advancement of electronic materials.

      PubDate: 2018-02-05T07:21:14Z
       
  • Bending and wrinkling of composite fiber preforms and prepregs. A review
           and new developments in the draping simulations
    • Abstract: Publication date: 15 May 2018
      Source:Composites Part B: Engineering, Volume 141
      Author(s): P. Boisse, J. Colmars, N. Hamila, N. Naouar, Q. Steer
      Bending properties play a significant role in the forming of textile composites reinforcements, particularly in determining the shape of wrinkles. The physics related to the bending of fibrous reinforcements is specific. Bending is due to slippage between the fibers and since the fibers are quasi-inextensible, standard plate and shell theories are irrelevant. To measure bending characteristics, three experimental tests (and their variants) have been developed in the last decades, and efforts are currently devoted to extending and improving these tests. From their results, simulations can be performed by introducing a flexural energy related to the bending moment and the curvature. In particular, wrinkles during forming can be simulated. In the case of 3D modeling of thick reinforcements, the use of generalized continuum mechanics model is necessary because of the bending stiffness of each fiber and the slippage between fibers. In order to simulate textile reinforcements with shells, some shell approaches, different of the standard theories, can correctly calculate the rotations of textile reinforcement normals.

      PubDate: 2018-02-05T07:21:14Z
       
  • Microwave absorption and mechanical performance of α-MnO2 nanostructures
           grown on woven Kevlar fiber/reduced graphene oxide-polyaniline nanofiber
           array-reinforced polyester resin composites
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Ankita Hazarika, Biplab K. Deka, Kyungil Kong, DoYoung Kim, Young-Woo Nam, Jae-Hun Choi, Chun-Gon Kim, Young-Bin Park, Hyung Wook Park
      Various morphologies of α-MnO2 nanostructures were synthesized on the surface of woven Kevlar fiber (WKF) by hydrothermal method under different reaction conditions. Reduced graphene oxide-polyaniline nanofiber (RGO-PANI) arrays were synthesized by an in situ dilute polymerization technique and then dispersed within polyester (PES) resin. High-performance composites based on α-MnO2-grown WKF and RGO-PANI array-dispersed PES were fabricated with effective microwave-absorbing and mechanical properties by vacuum-assisted resin transfer molding (VARTM). WKF/MnO2 nanofibers/PES/PANI-RGO (2%) composites showed superior electromagnetic parameters in the frequency range of 1–18 GHz. The reflection loss (RL) of WKF/MnO2 nanofibers/PES/PANI-RGO (2.0%) was −36.5 dB at an absorbing frequency of 11.8 GHz, which has not been reported before. A higher tensile strength (160.12%), modulus (104.43%), and absorbed impact energy (207%) were observed for α-MnO2 nanofibers, compared with other morphologies of α-MnO2-incorporated WKF composites and the properties were enhanced with an increased percentage of PANI-RGO.

      PubDate: 2018-02-05T07:21:14Z
       
  • On the post-curing of graphene nanoplatelets reinforced hand lay-up glass
           fabric/epoxy nanocomposites
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): G.V. Seretis, S.F. Nitodas, P.D. Mimigianni, G.N. Kouzilos, D.E. Manolakos, C.G. Provatidis
      Literature can hardly be found on the effect of post-curing parameters on the performance of graphene reinforced nanocomposites. In this study, the effect of post-curing temperature and time on the mechanical and thermal properties of graphene nanoplatelets (GNPs) reinforced E-glass fabric/epoxy nanocomposites is investigated. Tensile, flexural and TGA tests were carried out for the mechanical and thermal characterization. An opposite relation between mechanical and thermal properties was observed. Also, the already reported decrease of the mechanical properties while increasing the post-curing time begins later (after 4 h and 6 h for tensile and flexural tests, respectively) for the GNPs nanocomposites.

      PubDate: 2018-02-05T07:21:14Z
       
  • Improved mechanical properties of bitumen modified with acetylated
           cellulose fibers
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Solenne Desseaux, Salomé dos Santos, Thomas Geiger, Philippe Tingaut, Tanja Zimmermann, Manfred N. Partl, Lily D. Poulikakos
      Temperature sensitivity of bitumen modified with acetylated microfibrillated cellulose (MFCac), both in the low and high temperature ranges, is significantly decreased. The complex shear modulus for an MFCac content of 2 wt% was 10 times higher than for bitumen alone. In addition the phase angle at high temperatures indicates increased elastic behavior that results in favorable properties with respect to rutting. On the low temperature side (−25 °C), the deformation to failure in fracture toughness tests was around 100 times higher with MFCac modified bitumen than for the non-modified one whereas the failure forces were similar.
      Graphical abstract image

      PubDate: 2018-02-05T07:21:14Z
       
  • Elastoplastic-damaged meso-scale modelling of concrete with recycled
           aggregates
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): G. Mazzucco, G. Xotta, B. Pomaro, V.A. Salomoni, F. Faleschini
      The use of recycled concrete aggregates is very attractive from the point of view of reducing concrete production costs and of sustainability. A peculiar origin of such aggregates is that of demolitions of pre-existing concrete buildings. Scope of this work is to analyse the challenging aspects of recycled aggregates modelling in concrete mixtures and to define a procedure to cope with them. Particularly, numerical analyses dealing with the mechanical behaviour of concrete mixtures made of natural and recycled aggregates are here performed at the meso-scale level, distinguishing between concrete paste and aggregates themselves. Some compelling issues for the modelling phase are addressed, i.e.: i) the correct reproduction of recycled aggregates within the concrete samples, which involves both the acquisition of the external geometry of the aggregates and their random disposition in the sample, ii) the characterization of the mechanical constitutive law of the composite. An elastic-plastic-damaged formulation is adopted for representing the constitutive behaviour of mortar and cement matrix; the procedure is calibrated and validated so proving its predictability features when describing damage triggering and spreading within concrete samples subjected to compressive loads.

      PubDate: 2018-02-05T07:21:14Z
       
  • Synthesis and characterization of titania-silica fume composites and their
           influence on the strength of self-cleaning mortar
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Andrei-Vlad Zanfir, Georgeta Voicu, Alina-Ioana Bădănoiu, Daniela Gogan, Ovidiu Oprea, Eugeniu Vasile
      This paper describes the sol-gel synthesis and characterization of a titania-silica fume composite obtained by the coating of silica fume (SF) particles with TiO2 photocatalyst nanoparticles. SEM and TEM images revealed the presence of TiO2 nano-spheres at the surface of bigger SF spherical particles and HRTM confirmed the presence of anatase form. The methylene blue photodegradation tests have shown that photocatalytic activity of TiO2-SF composites is improved in the first hours, due to an efficient dispersion of the TiO2 nanoparticles at the surface of SF particles. The TiO2-SF composite powders have a good pozzolanic activity and can be used for the partial substitution of Portland cement in the preparation of self-cleaning mortar. The values of compressive strength of mortars with 3 wt%. TiO2-SF powders are higher as compared with those assessed for reference (Portland cement mortar), especially for longer hardening times (28, 90 days).

      PubDate: 2018-02-05T07:21:14Z
       
  • Extraction and investigation of lightweight and porous natural fiber from
           Conium maculatum as a potential reinforcement for composite materials in
           transportation
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Ahmet Çağrı Kılınç, Serhan Köktaş, Yasemin Seki, Metehan Atagür, Ramazan Dalmış, Ümit Halis Erdoğan, Ali Aydın Göktaş, M. Özgür Seydibeyoğlu
      The aim of the study is to evaluate the use of undervalued Conium maculatum plant fibersas a new potential for the reinforcement of composite materials. In this research, new natural cellulosic fibers were extracted from Conium maculatum plant using conventional water retting method. Mechanical strength, crystallography, thermal stability and chemical structure of Conium maculatumfibers were investigated by single fiber tensile testing, X-Ray Diffraction Analysis (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Additionally, surface topography and surface chemistry were analyzed by Scanning Electron Microscope (SEM) and X-Ray Photoelectron Spectroscopy (XPS), respectively. SEM images revealed that the fiber has a porous structure which is very critical for the transportation industry. XPS results indicated that the fiber surface is hydrophobic which is very critical for the composites prepared with hydrophobic matrices like polyolefin materials. Chemical composition of the fibers was also determined. The main components of Conium maculatumfibers such as cellulose, hemicellulose and lignin were reported to be 49.5, 32.2 and 8.6%, respectively. The crystallinity index was stated as 46.4%. The fibers are thermally stable up to 260 °C. Tensile strength of Conium maculatum fibers were determined as 327.89 ± 67.41 MPa. This research paper suggests a novel sustainable ecological material for reinforcement in polymeric composites.

      PubDate: 2017-12-27T01:37:29Z
       
  • Exfoliated boron nitride nanosheet/MWCNT hybrid composite for thermal
           conductive material via epoxy wetting
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Kiho Kim, Jooheon Kim
      Herein, we describe the fabrication of thermally conductive composites based on an epoxy matrix with a hybrid filler of hexagonal boron nitride (h-BN) and multi-walled carbon nanotubes (MWCNTs) via the wetting method. The h-BN particles were exfoliated to boron nitride nanosheets (BNNSs) by heating in a tubular furnace with steam and sonication. The h-BN particles in the composite were densely packed and oriented almost perpendicular to the bottom. On the other hand, the BNNSs were more loosely packed and randomly oriented, and exhibited higher through-plane thermal conductivity despite the low filler content. After the incorporation of MWCNTs, the filler thermal conductivities of both the composites significantly increased. In particular, 9 wt% of MWCNTs was sufficient to increase the thermal conductivity of the BNNS composite from 3.12 to 4.25 W m−1 K−1 because of the intercalation of the nanotubes between the BNNSs, which provided a three-dimensional heat flow path. Moreover, the MWCNTs interrupted the dense particle packing and the filler concentration was reduced from 56.7 to 43.8 wt%. In the case of h-BN composite, this effect was relatively weak because the nanotubes were agglomerated between the micron-sized BN particles.

      PubDate: 2017-12-27T01:37:29Z
       
  • Characterization of hybrid pultruded structural products based on preforms
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): F.J.G. Silva, A. Baptista, G. Pinto, R.D.S.G. Campilho, M.C.S. Ribeiro
      Pultrusion is a widely known technique for production of constant cross-section profiles, such as bars, L-shape or T-shape profiles, as well as structural tubes in polymer matrix composite materials. In some applications, requirements are demanding for profiles able to provide better thermal or sound insulation or needing a slightly higher moment of inertia without increasing the ratio between weight and strength. In such cases, hybrid pultruded profiles with core based on preforms are a possible solution. After obtaining prototypes according to the methodologies described in a previous work, and as a complement to that work, it is necessary to verify if the properties of these hybrid profiles correspond to the initial expectations, by performing destructive and non-destructive tests. Thus, tensile, compression and bending tests were performed, in order to verify the mechanical benefits achieved through the core introduction into the hollow profile and to analyse the added value brought by these new products. These values, once properly validated, can be added to existing databases related to structural calculation programs, enabling to get the adequate values for calculations regarding this kind of profiles. In addition, thermal and acoustic insulation tests were performed, in order to quantify the physical improvements achieved regarding these properties, which are extremely important in specific applications linked to the civil construction and public works, among many others. The cored profiles showed a strong adhesion between the profile and any kind of core tested as well as improved properties in terms of thermal insulation and moment of inertia. However, the sound insulation did not present significant improvements, probably due to GFRP profile external rigidity and consequent reflection.

      PubDate: 2017-12-27T01:37:29Z
       
  • Strengthening mechanisms in ultrasonically processed aluminium matrix
           composite with in-situ Al3Ti by salt addition
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Rahul Gupta, G.P. Chaudhari, B.S.S. Daniel
      Al3Ti reinforced Aluminium composites with different weight percent of Al3Ti particles were developed by in-situ reaction of aluminium alloy with potassium hexafluorotitanate (K2TiF6). Ultrasonication of the aluminium melt during salt reaction was carried out to refine the cast microstructure and achieve better dispersion of in-situ formed Al3Ti particles. The in-situ composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Al3Ti particles generated in the melt promoted heterogeneous nucleation, which was responsible for grain refinement of the cast microstructure. The well dispersed Al3Ti significantly improved the mechanical properties including ductility, yield strength (YS), ultimate tensile strength (UTS) and hardness. The dominant strengthening mechanism in the composite was the thermal mismatch strengthening followed by Hall-Petch strengthening.

      PubDate: 2017-12-27T01:37:29Z
       
  • Multi-stiffness topology optimization of zero Poisson's ratio cellular
           structures
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Jian Huang, Qiuhua Zhang, Fabrizio Scarpa, Yanju Liu, Jinsong Leng
      This work features a multi-stiffness topology optimization of a zero Poisson's ratio cellular structure for morphing skin applications. The optimization is performed with stiffness constraints to minimize the weight by using a state-of-the-art solid isotropic microstructure with penalty (SIMP) method. The topology optimization has been performed to minimize flatwise compressive and transverse shear moduli for aerodynamic pressures and shear forces. The multi-stiffness topology optimization is performed using a norm method with weighting coefficients. Both the single-stiffness and the multi-stiffness topology optimization have generated new honeycomb design by imposing symmetry conditions and geometric post-processing to avoid the presence of stress concentrations. The mechanical performances of the new honeycomb designs are validated using two approaches: one based on force boundary conditions (HyperWorks) and another with displacement BCs (ANSYS). The work shows some alternate potential topologies and configurations of cellular structures for lightweight zero Poisson's ratio honeycomb designs.

      PubDate: 2017-12-27T01:37:29Z
       
  • Multifunctional graphene/POSS epoxy resin tailored for aircraft lightning
           strike protection
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Marialuigia Raimondo, Liberata Guadagno, Vito Speranza, Leila Bonnaud, Philippe Dubois, Khalid Lafdi
      This paper presents a first successful attempt to obtain a conductivity mapping at nanoscale level of a new multifunctional fire retardant graphene/polyhedral oligomeric silsesquioxane (POSS) epoxy resin using Tunneling Atomic Force Microscopy (TUNA) that is a very sensitive mode by which ultra-low currents ranging from 80 fA to 120 pA can be measured. The multifunctional material, specifically designed to meet structural aeronautical requirements, such as suitable thermal stability, fire resistance, mechanical performance and electrical conductivity, has proven to be a promising candidate in the field of aeronautic and aerospace composites. The results also highlight the great potentiality of TUNA technique to analyze conductive networks at nanodomain level. Through simultaneous topographic and current images acquisition, this technique enables a direct correlation of local topography with electrical properties of the nanofiller based samples. The intrinsic electrical conductivity of the manufactured polymeric systems allows TUNA measurements without using electrical conductive paint, which is usually employed for polymeric systems to ensure effective electrical contacts to the ground.

      PubDate: 2017-12-27T01:37:29Z
       
  • Failure modes in FRCM systems with dry and pre-impregnated carbon yarns:
           Experiments and modeling
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Jacopo Donnini, Giovanni Lancioni, Valeria Corinaldesi
      Fiber Reinforced Cementitious Matrix (FRCM) systems have emerged in recent years as an effective tool for strengthening and retrofitting of the existing built heritage. The effectiveness of FRCM systems is strongly related to the bond developed at the interface between inorganic matrix and fabric reinforcement and between the inorganic matrix and the substrate. However, since the major weakness is often located at the matrix-to-fiber interface, the study of stress-transfer mechanisms between fibers and matrix, and a better understanding of the failure processes become of fundamental importance. In this paper, interface bond-slip relations are derived from pull out tests on multifilament carbon yarns embedded in a cementitious matrix. Two different types of yarns are investigated, dry and pre-impregnated with epoxy resin. A variational model able to reproduce the mechanisms of interface debonding and frictional slippage observed in experiments is developed, where the constitutive parameters are calibrated on the base of the experimental data available from pull out tests. The model is implemented in a finite elements code, and pull out and double shear bond tests on masonry substrates are simulated. Finally, numerical results are compared with experimental evidences.

      PubDate: 2017-12-27T01:37:29Z
       
  • Evaluation of hybrid effect on the thermomechanical and mechanical
           properties of calcite/SGF/PP hybrid composites
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Oguzkan Senturk, Ahmet Emin Senturk, Mehmet Palabiyik
      The thermomechanical and mechanical properties of calcite-filled polypropylene (PP) composites and their short glass fiber (SGF)-reinforced hybrid composites were studied herein. The interfacial adhesion strength and the influence of the combined particle filler and short fiber content were examined to characterize the positive hybrid effect. The thermal stabilities of the hybrid composites were analyzed by thermogravimetric/differential thermal analysis. Consequently, the increase in the calcite and SGF contents was caused by the increasing melting and decomposition temperatures. In contrast, the calcite and SGF contents had minor effect on the melting temperatures. In the mechanical tests, the samples were characterized by tensile, flexural, and unnotch impact properties. The presence of calcite and SGF in the composites increased the interfacial adhesion strength and enhanced the tensile and bending properties, but reduced the tensile elongation and the impact strength. The effectiveness of the interfacial adhesion strength was characterized by a dynamic mechanical analysis. The viscoelastic properties indicated that the fiber matrix interaction was enhanced by incorporation of calcite and SGF. The morphology of the fracture surfaces was investigated by scanning electron microscopy. These observations were proven by comparing the thermomechanical and mechanical test results aimed to identify the SGF/matrix interaction and the positive hybrid effect.

      PubDate: 2017-12-27T01:37:29Z
       
  • First observation of the effect of the layer printing sequence on the
           molecular structure of three-dimensionally printed polymer, as shown by
           in-plane capacitance measurement
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Naga B. Gundrati, Patatri Chakraborty, Chi Zhou, D.D.L. Chung
      The layer printing sequence in three-dimensional (3D) printing affects the molecular structure of the printed layers, as shown for bottom-up stereolithography printing using an ultraviolet-curable acrylate ester resin. The first printed layer has less molecular alignment than the last printed layer, due to the longer ultraviolet exposure and consequent more curing in the former. Increasing the layer thickness from 12.4 to 26.3 μm decreases this effect, due to the greater molecular alignment for a smaller layer thickness. These results are obtained by measuring the in-plane capacitance for the two opposite surfaces of the printed material. The technique is unprecedented in 3D printing.

      PubDate: 2017-12-27T01:37:29Z
       
  • Dielectric properties and thermal conductivity of epoxy composites using
           core/shell structured Si/SiO2/Polydopamine
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Zhengdong Wang, Yonghong Cheng, Mengmeng Yang, Jialiang Huang, Daxian Cao, Siyu Chen, Qian Xie, Wanxi Lou, Hongjing Wu
      We report the fabrication of epoxy-based composites using well-designed core/shell Si/SiO2 (denoted as Si*) and core/shell/shell structured Si/SiO2/Polydopamine (denoted as Si*@PDA) particles as fillers, which exhibit improved dielectric properties and thermal conductivity. Using the core-shell Si* and Si*@PDA particles as fillers in the epoxy-based composites, the dielectric loss tangent is remarkably suppressed and the volume resistivity is apparently enhanced, as compared with that using raw Si particles as fillers. Moreover, the Si*@PDA composites have higher dielectric constant and lower loss tangent. For instance, the dielectric constant of Si*@PDA/epoxy composite with 33.8 vol% filler content is up to 19.8 at room temperature at 100 Hz, which is nearly 5.3 times of that of the pure epoxy polymer (3.4), while its loss tangent is only 0.085. Additionally, the core-shell particle-based composites still possess a high thermal conductivity.
      Graphical abstract image

      PubDate: 2017-12-27T01:37:29Z
       
  • Multidisciplinary tool for composite wind blade design &amp; analysis
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): J. Wang, P. Simacek, N. Gupta, S.G. Advani
      Composite part design process proceeds with the designers' gradually eliminating the uncertainty in design parameters. However, the analysis tools that have been developed to aid this process require the designer to decide precise parameter values at the very beginning of the design stage which reduces their effectiveness. To improve their utility, this paper introduces a management strategy to integrate multi-disciplinary analysis modules with CAD software and account for design uncertainties during the design stage. Interdependent cross-disciplinary design parameters are separated in accordance with their uncertainty levels, and different fidelity analysis models are assigned to each set of parameters accordingly. As the design process proceeds, more precise design parameters are input for analysis modules that have higher level of fidelity. This management method resembles the practical design flow and is therefore intuitive to the designer in the decision-making process. An example using this approach to develop multidisciplinary composite wind blade with such design and analysis software is shown to illustrate its effectiveness and efficiency in complex composite part design.

      PubDate: 2017-12-27T01:37:29Z
       
  • In situ electrochemical synthesis of silver-doped poly(vinyl
           alcohol)/graphene composite hydrogels and their physico-chemical and
           thermal properties
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): Mohamed M. Abudabbus, Ivana Jevremović, Katarina Nešović, Aleksandra Perić-Grujić, Kyong Yop Rhee, Vesna Mišković-Stanković
      This paper presents silver/poly(vinyl alcohol) (Ag/PVA) and silver/poly(vinyl alcohol)/graphene (Ag/PVA/Gr) composites prepared by the immobilization of silver nanoparticles (AgNPs) in PVA and PVA/Gr hydrogel discs previously cross linked by the freezing/thawing method. The AgNPs inside the hydrogel matrices were synthesized following an innovative in situ method of electrochemical reduction of Ag+ ions within PVA and PVA/Gr hydrogel discs. In addition, the novel materials introduced here were characterized by UV–visible spectroscopy, cyclic voltammetry, Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, silver release measurements, and thermogravimetric analysis. The effective immobilization of the AgNPs inside the PVA and PVA/Gr hydrogel networks was achieved by their bonding with the exposed hydroxyl groups in PVA. Also, the incorporation of graphene into the PVA matrix and the bonding between PVA molecules and incorporated graphene sheets improves thermal stability of Ag/PVA/Gr and prevents aggregation and growth of AgNPs as observed by Fourier transform infrared spectroscopy and field emission scanning electron microscopy.

      PubDate: 2017-12-27T01:37:29Z
       
  • Enhancing the out-of-plane performance of masonry walls using engineered
           cementitious composite
    • Abstract: Publication date: 1 May 2018
      Source:Composites Part B: Engineering, Volume 140
      Author(s): S. Pourfalah, B. Suryanto, D.M. Cotsovos
      A novel technique for enhancing the out-of-plane behaviour of masonry infill walls is proposed herein. The technique involves the use of a thin layer of engineered cementitious composite (ECC) which is fully or partially bonded onto the face of masonry walls. To investigate the feasibility of this technique, the present research focuses on studying the behaviour of a series of beam-like masonry specimens with or without an ECC retrofitting layer subjected to a four-point bending load. The load is applied monotonically to failure at rates of 1 mm/min or 200 mm/min. The results show that the ECC-retrofitted specimens exhibited a significant enhancement in the out-of-plane performance in terms of strength, stiffness and deflection compared to the un-strengthened specimens. It is observed that specimens with a partially bonded ECC layer out-performed their counterparts having a fully bonded ECC layer. The partially de-bonding technique is found to allow the ECC layer achieve its full ductility potential. The results also reveal that specimens subjected to an elevated loading rate exhibited a greater load-carrying capacity and stiffness but lower deflection.

      PubDate: 2017-12-27T01:37:29Z
       
 
 
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