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ENGINEERING (1267 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 8)
3D Research     Hybrid Journal   (Followers: 21)
AAPG Bulletin     Hybrid Journal   (Followers: 8)
AASRI Procedia     Open Access   (Followers: 14)
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: 273)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 3)
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: 7)
Advanced Journal of Graduate Research     Open Access  
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 5)
Advanced Science Letters     Full-text available via subscription   (Followers: 10)
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: 5)
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: 17)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 43)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 44)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 3)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 6)
AIChE Journal     Hybrid Journal   (Followers: 35)
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: 26)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 10)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 24)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Antarctic Science     Hybrid Journal   (Followers: 1)
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: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 11)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 5)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
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: 28)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 1)
BER : Motor Trade Survey     Full-text available via subscription  
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 1)
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: 3)
Beyond : Undergraduate Research Journal     Open Access  
Bhakti Persada : Jurnal Aplikasi IPTEKS     Open Access  
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Bilge International Journal of Science and Technology Research     Open Access  
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 21)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 37)
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   (Followers: 1)
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Bitlis Eren University Journal of Science and Technology     Open Access  
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: 12)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 13)
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   (Followers: 2)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 31)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 42)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Thermal Engineering     Open Access   (Followers: 5)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
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  
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: 3)
CienciaUAT     Open Access   (Followers: 1)
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: 13)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
Clinical Science     Full-text available via subscription   (Followers: 9)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 6)
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: 14)
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: 28)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Composite Structures     Hybrid Journal   (Followers: 277)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 208)
Composites Part B : Engineering     Hybrid Journal   (Followers: 249)
Composites Science and Technology     Hybrid Journal   (Followers: 193)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 16)
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: 31)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 8)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 5)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 7)
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)

        1 2 3 4 5 6 7 | Last

Journal Cover
Composites Part B : Engineering
Journal Prestige (SJR): 2.039
Citation Impact (citeScore): 5
Number of Followers: 249  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1359-8368
Published by Elsevier Homepage  [3163 journals]
  • Thermo-mechanical performances of polypropylene biocomposites based on
           untreated, treated and compatibilized spent coffee grounds
    • Authors: Hamid Essabir; Marya Raji; Sana Ait Laaziz; Denis Rodrique; Rachid Bouhfid; Abou el kacem Qaiss
      Pages: 1 - 11
      Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Hamid Essabir, Marya Raji, Sana Ait Laaziz, Denis Rodrique, Rachid Bouhfid, Abou el kacem Qaiss
      In this work, biocomposites were produced by compounding polypropylene (PP) with spent coffee grounds (SCG) obtained after soluble coffee preparation. The samples were prepared by extrusion compounding and injection molding using different SCG contents (0, 5, 10, 15 and 20wt.) in order to investigate the effect of particle loading on the thermal, rheological and mechanical properties. Then, the effect of bleaching treatments and the use of compatibilizers (silane and styrene-ethylene-butene-styrene-graft-maleic anhydride) on the biocomposites properties at 15 wt% was examined. The results showed that good SCG dispersion and distribution into PP was achieved and that bleaching led to better interfacial interaction, which was further increased by using a coupling agent. As a result, the tensile and torsion properties were increased.

      PubDate: 2018-05-17T16:03:54Z
      DOI: 10.1016/j.compositesb.2018.05.020
      Issue No: Vol. 149 (2018)
  • Experimental study on CFRP-strengthened steel beams
    • Authors: Tomasz W. Siwowski; Paulina Siwowska
      Pages: 12 - 21
      Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Tomasz W. Siwowski, Paulina Siwowska
      Recently, as a viable alternative to strengthening or repairing steel bridges with welded or bolted plates, bonded CFRP plates have been used. The main goal of the presented study is to compare the flexural behaviour of steel beams strengthened with the CFRP plates. The research has evaluated two strengthening schemes: adhesive-bonded passive plates and adhesive-bonded prestressed or active plates. The ductility and yield/ultimate carrying capacity of steel beams as well as the effectiveness of strengthening have been established in each case. The failure modes of the strengthened beams comprised the CFRP plate debonding or plate rupture, depending on the strengthening system (passive or active) and some system parameters, as the CFRP modulus of elasticity, end plate anchoring and plate prestressing level. The influence of these parameters on the strengthening effectiveness has been also discussed.

      PubDate: 2018-05-17T16:03:54Z
      DOI: 10.1016/j.compositesb.2018.04.060
      Issue No: Vol. 149 (2018)
  • Single and repeated impact behaviors of bio-sandwich structures consisting
           of thermoplastic face sheets and different balsa core thicknesses
    • Authors: Okan Ozdemir; Nahit Oztoprak; Halis Kandas
      Pages: 49 - 57
      Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Okan Ozdemir, Nahit Oztoprak, Halis Kandas
      This paper aims to investigate the single and repeated impact behaviors of bio-sandwich structures consisting of E-glass fiber – reinforced thermoplastic face sheets and balsa cores. Low velocity impact tests were performed using a drop-weight impact machine under a hemispherical impactor. Preliminary single low velocity impact loadings were applied to the bio-sandwich composites with different core thicknesses (namely 15 and 25 mm) so as to obtain the energy limits which were ranged from fully elastic level (10 J) to perforation energy level (80 J). Impact behaviors and damage mechanisms which occurred at both face sheets and internal parts of the balsa core were elucidated through the energy profile diagrams and force – deformation (F-D) curves under low velocity single impact loadings. Besides, low velocity repeated impact tests of the bio-sandwich structures were performed with the same impact energy levels. Repetitive impact behaviors were also investigated with F-D curves at some specific repeated impact numbers. Impact failures which occurred in the upside and bottom of composite structures were detected with digital camera. According to the experimental findings, it was concluded that the total number of impact loads under impact energy level of 10 J until perforation were 38 for the sandwich structures with 15 mm balsa core thickness while it was 98 for the sandwich structures with 25 mm balsa core thickness. Based upon the test results, the number of impacts for perforation (N r ) under smaller impact energies without testing was easily predicted with the derived equation in the form of E i = a N r b , where E i represents the impact energy while a and b are the constants.

      PubDate: 2018-05-17T16:03:54Z
      DOI: 10.1016/j.compositesb.2018.05.016
      Issue No: Vol. 149 (2018)
  • Hybrid bio-composites reinforced with sisal-glass fibres and Portland
           cement particles: A statistical approach
    • Authors: Sergio Luiz Moni Ribeiro Filho; Pablo Resende Oliveira; Luciano Machado Gomes Vieira; Tulio Hallak Panzera; Rodrigo Teixeira Santos Freire; Fabrizio Scarpa
      Pages: 58 - 65
      Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Sergio Luiz Moni Ribeiro Filho, Pablo Resende Oliveira, Luciano Machado Gomes Vieira, Tulio Hallak Panzera, Rodrigo Teixeira Santos Freire, Fabrizio Scarpa
      The hybrid configuration of bio-reinforced composites has established a new extended boundary for the development of pro-ecological technologies due to light weight, moderate specific strength, low cost, environmental benefits, and potential applications of natural components. This work investigates the physical and mechanical properties of hybrid composites made of sisal/glass fibres and Portland cement inclusions. A full factorial design was generated to identify the effects of the stacking sequence and cement particles on the flexural strength, flexural stiffness, apparent density, apparent porosity and water absorption of the composites. The significant contributions of these main factors and their interactions were determined via Design of Experiments (DoE) and Analysis of Variance (ANOVA). The fracture features and damage mechanisms of hybrid composite were also reported. The inclusion of cement microparticles led to an increased apparent porosity, as well as enhanced water absorption, flexural stiffness and flexural strength of the hybrid composites. The mechanical properties were strongly dependent on the fibre stacking sequence, which accounts for approximately 98% of the effects observed. Moreover, the stacking sequence affected the damage mechanism of the bio-composites. Finally, the replacement of glass fibres by unidirectional sisal reinforcements may potentially improve the specific properties in structural applications with an environmental sustainable footprint.

      PubDate: 2018-05-17T16:03:54Z
      DOI: 10.1016/j.compositesb.2018.05.019
      Issue No: Vol. 149 (2018)
  • Hierarchical micromechanical modeling of the viscoelastic behavior coupled
           to damage in SMC and SMC-hybrid composites
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Dimitrios Anagnostou, George Chatzigeorgiou, Yves Chemisky, Fodil Meraghni
      The aim of this paper is to study, through a multiscale analysis, the viscoelastic behavior of glass reinforced sheet molding compound (SMC) composites and SMC-hybrid composites mixing two types of bundle reinforcement: glass and carbon fibers. SMC exhibit more than two distinct characteristic length scales, so that a sequence of scale transitions is required to obtain the overall behavior of the composite. An analytical procedure is used consisting of properly selected well-established micromechanical methods like the Mori-Tanaka (MTM) and the composite cylinders (CCM) accounting for each scale transition. After selecting a representative volume element (RVE) for each scale, the material response of any given length scale is described on the basis of the homogenized behavior of the next finer one. This hierarchical approach is appropriately extended to the viscoelastic domain to account for the time dependent overall response of the SMC composite material. The anisotropic damage has been introduced through a micromechanical model considering matrix penny-shape microcrack density inside bundles. The capabilities of the hierarchical modeling are illustrated with various parametric studies and simulation of experimental data for glass-based SMC composites.

      PubDate: 2018-06-18T02:23:54Z
  • Nanoporous gold reinforced with carbon based nanomaterials: A molecular
           dynamics study
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Deniz Ezgi Gulmez, Yunus Onur Yildiz, Mesut Kirca
      Considering the fact that carbon based nanostructures (CBNs) and nanoporous (np) metals are very promising for future applications, the main motivation of this study is to improve the mechanical characteristics of np metals by employing CBNs including graphene nanoribbons (GNRs), fullerenes and CNTs within the cellular voids by presenting a new metal-carbon nanocomposite material. For this purpose, a Voronoi-based atomistic modeling technique is used to obtain numerical models of the proposed hybrid structures and their mechanical properties under tensile and compressive loading conditions are investigated by classical molecular dynamics. Instead of reinforcing with discrete units, a heat welding procedure is applied to generate a covalently bonded network of carbon based structures. Results clearly indicate that the utilization of carbon based nanostructures enhances both tensile and compressive response of np metals significantly while a minor microstructural change is observed within the crystal structure. The major effect is observed especially on the yield and post-yield behavior of np structures, while the elastic modulus is not affected remarkably. The main reason for the enhancement is greatly attributed to the covalent bonding generated between the CBN units. As an indicator, the np specimen with GNR network presents higher tensile performance compared to the other CBN units due to larger number of covalent bonds. The proposed hybridization can also be evaluated for the enhancement on the thermal and electrochemical performance of the np metals.

      PubDate: 2018-06-18T02:23:54Z
  • Application of sinusoidal shear deformation theory and physical neutral
           surface to analysis of functionally graded piezoelectric plate
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Mohammad Arefi, Elyas Mohammad-Rezaei Bidgoli, Rossana Dimitri, Michele Bacciocchi, Francesco Tornabene
      The concept of neutral surface for a Functionally Graded Piezoelectric (FGP) plate is developed in this paper. The electro-elastic analysis of a FGP plate resting on Winkler-Pasternak foundation is performed in the theoretical framework provided by a two-variable sinusoidal shear deformation theory, including the aforementioned concept of neutral surface. First, the location of neutral surface is defined with respect to the position of the middle surface and then the governing bending equations are derived using the principle of virtual work. An analytical method is presented to investigate the variation of the displacement and stress components in terms of the main parameters of the model, which are volume fraction exponent of the constituents, the electric potential and foundation parameters. The numerical results are validated through the comparison with available references. The numerical results prove that the value of transverse bending deflection is greater than the corresponding shear deflection. In addition, it can be observed that the volume fraction exponent has peculiar influence on the distribution of displacements and stresses.

      PubDate: 2018-06-18T02:23:54Z
  • Multi-material adhesive joints for automotive industry
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): M.D. Banea, M. Rosioara, R.J.C. Carbas, L.F.M. da Silva
      The application of adhesively bonded joints in automotive industry has increased significantly in recent years mainly because of the potential for lighter weight vehicles, fuel savings, and reduced emissions. The principal benefits are design flexibility and joining of dissimilar and/or new materials, among others. On the other hand, the use of lightweight materials such as high strength steel, aluminum alloys as well as composites in making automotive body components to achieve a reduced vehicle mass has also continuously increased. In this paper, similar and multi-material adhesive joins were investigated experimentally and numerically. Several important factors, such as overlap length and adherend stiffness, influencing the strengths of multi-material adhesive joints were investigated. It was found that, for relatively short overlaps in SLJs bonded with structural modern tough adhesives, failure is dominated by adhesive global yielding and the influence of geometry and/or material combination on joint strength is not significant. Overall numerical values of the maximum load were very close to experimental results, validating the numerical methodology to predict the lap shear strength and providing the necessary data to explain the obtained behaviour.

      PubDate: 2018-06-18T02:23:54Z
  • Structural behaviour of hybrid glass beams with T cross-sections
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Giuseppe Campione, Francesco Cannella
      An experimental investigation regarding the flexural and the shear behaviour of glass beams with length 900, 1300, 1700 mm and T cross-section is presented and discussed. T cross-sections were obtained by assembling glass web and glass flange. Some specimens were also reinforced internally in the web with steel plates of thickness 6 mm and depth 25 and 50 mm placed at the bottom portion of the beams for the entire length of the beams themselves. Three specimens for each investigated series were tested in flexure focusing on the flexural and shear response through the determination of the load-deflection curves and the crack patterns at rupture identifying the effects of steel plates. The shear span to depth ratios a/d were 2, 3 and 4, respectively. A simple model is also presented for a preliminary design of composite glass beams able to predict the ultimate load including limit states due to glass cracking, flexural failure with glass crushing or plates yielding, shear compression and diagonal tension failure. The resistance is obtained from equilibrium conditions of a portion of beam enclosed between the support and shear span, taking also into account the presence of steel plates. The model is able to reproduce experimental results to the varying of the geometrical characteristics of beam, of the reinforcement area and on the type of reinforcement.

      PubDate: 2018-06-18T02:23:54Z
  • Quantitative analysis of QSI and LVI damage in GFRP unidirectional
           composite laminates by a new ultrasonic approach
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Anna Castellano, Aguinaldo Fraddosio, Mario Daniele Piccioni
      Our work is focused on a new experimental approach for the comparison between Quasi Static Indentation (QSI) damage and Low-Velocity Impact (LVI) damage in polymer composites starting from the results of ultrasonic goniometric immersion tests. In particular, the comparison is performed through the analysis of the additional anisotropy induced by the damage in unidirectional Glass Fiber-Reinforced Polymer (GFRP) composites due to QSI and LVI damage tests performed with a low level of the employed energy. To this aim, we ultrasonically reconstruct the acoustic curves (velocity curves and slowness curves) before and after the damage. Ultrasonic experiments are performed by using a goniometric ultrasonic immersion device designed and built at our laboratory, aimed at the mechanical characterization of anisotropic materials. We highlight differences and similarities between QSI and LVI damage starting from the analysis of the variations of the acoustic behavior and by using a suitable anisotropic damage model developed in the framework of the Continuum Damage Mechanics theory. The proposed experimental approach can be suitably developed for in situ investigations on low-velocity impact damage in polymer composite components.

      PubDate: 2018-06-18T02:23:54Z
  • High performance 3-node shell element for linear and geometrically
           nonlinear analysis of composite laminates
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Gil Rama, Dragan Marinkovic, Manfred Zehn
      Thin-walled structures hold primacy among modern engineering structures. All the advantages offered by the curved geometry and thinness of the walls come even more to the fore when combined with exquisite properties of fiber-reinforced composite laminates. Directionally dependant material properties open vast possibilities for tailoring global structural properties and, therewith, optimization. Successful design of such structures calls for high performance shell type finite elements. This paper presents a linear triangular shell element based on the equivalent single-layer approach and the first-order shear deformation theory. The shear locking effect is resolved by the descrete shear gap (DSG) approach combined with the cell smoothing technique. To improve the element performance with respect to the membrane behavior, the assumed natural deviatoric strains (ANDES) formulation is applied, with necessary modifications to meet the requirements of curved structures with anisotropic material properties. Geometric nonlinearities are addressed by the co-rotational formulation. Examples demonstrate the element applicability and performance.

      PubDate: 2018-06-18T02:23:54Z
  • Comparison of mechanical properties of C-S-H and portlandite between
           nano-indentation experiments and a modeling approach using various
           simulation techniques
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Jia Fu, Siham Kamali-Bernard, Fabrice Bernard, Marilyne Cornen
      This work focuses on elastic modulus of two main constituents of cement based materials: portlandite (CH) and Calcium Silicates Hydrates (C-S-H). At nano-scale, the single CH crystal using Density Functional Theory (DFT) is investigated and the homogenized elastic modulus is obtained to be assessed as the RVE unit, which is used in nano-indentation simulation. Then the monolithic C-S-H structure with the chemical formula: (CaO)1.67(SiO2)(H2O)1.75 is simulated during the stretch process at strain rate 10−3 ps−1 by Molecular Dynamics (MD) method using ClayFF field, and its averaged elastic modulus is used to assess Young's moduli of LD and HD C-S-H phases considering the porosity factor. Then at micro scale, FEM is used to simulate the nano-indentation test on ABAQUS software and Young moduli of CH and C-S-H phases are determined by the load-depth curve. Young modulus by the load-depth curve simulated is calculated to compare with the experimental one. The results show that: 1) the Young's modulus calculated by DFT and Reuss-Voigt-Hill (RVH) calculation is 45.46 GPa, which is in quite good agreement with experimental averaged value (39.88 GPa) and with the literature values (45.94 GPa by Laugesen, 52.4 GPa by Speziale et al., 44.69 GPa by Kerisit et al., 46.58 GPa by Holuj et al.). 2) Based on the elastic modulus of the monolithic C-S-H structure by MD simulations, the assessment results on LD C-S-H and HD C-S-H after homogenization are very close to nanoindentation experiments data. 3) By FEM method, the simulated P-h curve is adopted to compare the extent of deviation from the experimental values, which is within an acceptable relative error. The homogenized elastic properties of polycrystals can be obtained by elastic constants of single crystal (using DFT and RVH estimation), thus can be used to explain the relationship between structure and mechanical properties of CH from nano-scale to micro-scale. Results enable to provide useful parameters for composite cements systems modeling and a method to calculate elastic modulus of other similar structures.

      PubDate: 2018-06-18T02:23:54Z
  • Strengthened infilled RC frames: Continuum and macro modeling in nonlinear
           finite element analysis
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Matteo Breveglieri, Guido Camata, Enrico Spacone
      Strengthening and retrofitting masonry infill Reinforced Concrete (RC) frames is crucial due to the large use of this structural typology in earthquake-prone countries. Masonry infills can provide a positive and negative effect on the seismic response. A positive effect is due to the fact that the infills dissipate energy and therefore increase the overall damping. A negative effect may take place if their disposition is irregular or if they fail irregularly, thus the structure behavior becomes irregular. Furthermore, the infills generally stiffen the structure and thus increase the base shear force. It has been shown that by using an adequate infill strengthening technique, performance and safety of the structures and of the infills can be improved. Several models for Un-Reinforced Masonry (URM) infills have been developed in the past, but there is a lack of models available to describe the behavior of strengthened infilled frames. A simplified analytical strut and tie model is proposed based on the results obtained by Finite Element (FE) analyses. The mechanical characteristics of the tension tie and of the compression strut depend on the stiffness and strength of the reinforcement in addition to the geometrical and mechanical parameters of the infilled frame. The proposed model is validated with experimental results of a Carbon Fiber Reinforced Polymer (CFRP) strengthened infilled RC frame. The experimental data are reproduced by means of continuum FE models in order to assess the influence of various parameters on the seismic response and to calibrate the simplified model's parameters. Lateral stiffness and strength obtained with this simplified model show a good agreement with the experimental results and the continuum FE models.

      PubDate: 2018-06-18T02:23:54Z
  • New evaluation of interfacial and mechanical properties of thermally-
           treated Pine/CFRP composites using electrical resistance measurement
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Pyeong-Su Shin, Jong-Hyun Kim, Yeong-Min Baek, Ha-Seung Park, Dong-Jun Kwon, Sun-Ok Moon, K. Lawrence DeVries, Joung-Man Park
      Interfacial and mechanical properties of two thermally-treated (at 160 and 200 °C) pine/carbon fiber reinforced plastic (CFRP) composites were evaluated using mechanical wettability and electrical resistance (ER) methods. The wetting affinity between pine and epoxy adhesive and the associated spreading of epoxy resin on pine a surface was measured by placing drops of epoxy directly on the surface. Izod, 3-point bending and lap shear tests combined with ER measurements were used to determine the mechanical and interfacial properties of pine and pine/CFRP composites. The interfacial properties pine treated at 160 °C, exhibited the highest mechanical properties than those of the untreated and 200 °C treated pines. Changes in ER for the 160 °C treated pine for the Izod and 3-point bending tests results was small, but significant changes in ER were observed for both neat pine and pine treated at 200 °C for these tests. This is likely due to mechanical deterioration as a result of thermal degradation for 200 °C treated pine. This improvement in interfacial and mechanical properties at 200 °C is attributed to the hardening and reinforcement effects at the interface possibly due to the reduction in moisture in the pine. If the impact shock was applied to the pine parts in pine/CFRP composites, the monitored ER was dependent upon the thermal treated pine conditions. There was the some correlation among thermal treated pines, ER, and their fracture patterns.

      PubDate: 2018-06-18T02:23:54Z
  • On modal analysis of laminated glass: Usability of simplified methods and
           Enhanced Effective Thickness
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Alena Zemanová, Jan Zeman, Tomáš Janda, Jaroslav Schmidt, Michal Šejnoha
      This paper focuses on the modal analysis of laminated glass beams. In these multilayer elements, the stiff glass plates are connected by compliant interlayers with frequency and temperature-dependent behavior. The aim of our study is (i) to assess whether approximate techniques can accurately predict the behavior of laminated glass structures and (ii) to propose a simple tool for modal analysis based on the Enhanced Effective Thickness concept. For this purpose, we consider four approaches to the solution of the related nonlinear eigenvalue problem: a complex-eigenvalue solver based on the Newton method and three simplified approaches. In particular, we limit our attention to the modal strain energy method, the dynamic effective thickness method, and the Enhanced Effective Thickness method. A comparative study of free vibrating laminated glass beams is performed considering different geometries of cross-sections, boundary conditions, and material parameters for interlayers under two ambient temperatures. The viscoelastic response of polymer foils is represented by the generalized Maxwell model. We show that the simplified approaches predict natural frequencies with an acceptable accuracy for most of the examples. However, there is considerable scatter in predicted loss factors. The Enhanced Effective Thickness approach adjusted to modal analysis results in lower errors in both quantities compared to the other two simplified procedures. It reduces the extreme error in loss factors by half compared to the modal strain energy method and to one quarter compared to the original dynamic effective thickness method.

      PubDate: 2018-06-18T02:23:54Z
  • A phenomenological model for dynamic response of double-network hydrogel
           composite undergoing transient transition
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Haibao Lu, Xiaodong Wang, Xiaojuan Shi, Kai Yu, Yong Qing Fu
      We present a phenomenological model for dynamic deformation and mechanical response of double-network (with short-chained ionic network and long-chained covalent network) hydrogel composite based on theory of transient networks. Molecular structures and stress-strain relations of the hydrogel composite were investigated based on thermomechanical properties of the individual network. Constitutive relations were derived for its nonlinear viscoelastic responses and annihilation/reformation rates of active short chains were determined by means of Eyring formula. An extended Volokh model was proposed to separate effects of large strain hysteresis and anomalous viscoelastic relaxation on the hydrogel composite after strain reversal. Experimental results from rate-independent tests are well in agreement with that of the numerical simulations. This study provides a fundamental simulation tool for modelling and predicting mechanics and mechanisms of viscoelastic response and mechanical responses in double-network hydrogel composite.

      PubDate: 2018-06-18T02:23:54Z
  • Synthesis and characterization of eco-friendly carboxymethyl cellulose
           based carbon foam using electron beam irradiation
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Hong Gun Kim, Lee Ku Kwac, Yong-Sun Kim, Hye Kyoung Shin, Kyong-Yop Rhee
      Carbon foams were prepared by carbonization process without additional stabilization process after manufacturing carboxymethyl cellulose (CMC) composites using a facile electron beam irradiation (EBI) method. A gel fractionation technique was used to study cross-linking degree of infusible structure in the produced CMC composite materials. We observed an increase in cross-linking with increasing CA concentration and EBI doses between 20 kGy and 80 kGy. The CMC composite prepared using 4 wt% CA and 80 kGy EBI represents the highest gel fraction value of ∼98%, showing the highest carbon yields and compressive strength due to the increase of cross-linked parts in carbon foam obtained from these CMC composites, which lowers break defects after carbonization. In addition, available surface area was estimated via Brunauer-Emmett-Teller analysis of the carbon foam samples. The carbon foam produced from the CMC composite treated with 4 wt% CA via 80 kGy resulted in highest specific surface area of 372.06 m2/g and adsorption pore size of 2.20 nm indicating greater interaction between gas and the carbon atoms.

      PubDate: 2018-06-18T02:23:54Z
  • Highly stretchable and transparent electrode film based on SWCNT/Silver
           nanowire hybrid nanocomposite
    • Abstract: Publication date: 15 October 2018
      Source:Composites Part B: Engineering, Volume 151
      Author(s): Bu-Yeon Hwang, Sul-Hwa Choi, Ki-Wook Lee, Jin-Yeol Kim
      Highly stretchable, flexible, and transparent electrode films were fabricated based on a composite of silver nanowire (Ag NW) networks hybridized with single-walled carbon nanotubes (SWCNTs) in a sandwich structure, wherein a Ag NW-SWCNT hybrid network electrode was embedded between layers of polydimethylsiloxane and transparent polyurethane films. When 0.025 wt% SWCNTs were hybridized with Ag NWs, a Ag NW-SWCNT network electrode, which had excellent optical properties (very low haze value of less than 1% and 95% transmittance) and a low sheet resistance value of 30 Ω/sq, was obtained through the effective electrical transportation of the NW–NW, CNT–NW, and CNT–CNT junctions. The fabricated film heaters showed environmental endurance, and no significant performance degradation was observed after the films were kept at a high temperature of 85 °C and humidity of 85%. They also exhibited high stretchability up to 20%. Effective Joule heating can increase the temperature of the electrode films (30 Ω/sq) up to 68 °C at a bias of 11 V.

      PubDate: 2018-06-09T08:21:35Z
  • Mechanical buckling analysis of functionally graded power-based and carbon
           nanotubes-reinforced composite plates and curved panels
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): S. Zghal, A. Frikha, F. Dammak
      The main aim of this paper is to investigate the mechanical buckling behavior of functionally graded materials and carbon nanotubes-reinforced composite plates and curved panels. The governing equations are established using a double directors finite element shell model which induces a high-order distribution of the displacement field and takes into account the effect of transverse shear deformations. The effective material properties of functionally graded materials are estimated using a power law distribution and those of nanocomposites by an extended rule of mixture with some efficiency parameters. Uniform and four profiles of carbon nanotubes are considered to describe the distribution of these reinforcements through the thickness of the nanocomposite shell structure. A comparison study of the present results with those available in the literature is carried out for the isotropic case in order to prove the validity as well as the accuracy of the present model. Then, the results are extended to functionally graded materials and nanocomposites. The results reveal that the critical buckling load of plates and curved panels can be significantly increased as a result of a functionally graded reinforcement. They also show that the mechanical buckling behavior of such structures is significantly influenced by the plate aspect ratio, the length-to-thickness ratio, radius-to-thickness ratio, boundary conditions, power law index as well as the carbon nanotubes profiles and their volume fractions.

      PubDate: 2018-06-09T08:21:35Z
  • Design, analysis and optimization of anisogrid composite lattice conical
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Valerio G. Belardi, Pierluigi Fanelli, Francesco Vivio
      A methodology for structural analysis and optimal design of conical anisogrid composite lattice shell structures subject to different external loads concurrently applied and multiple stiffness constraints is presented. The critical buckling load of the anisogrid lattice conical structure is exactly assessed, independently of the buckling failure mode, by means of a discrete approach. The method makes use of a full FE parametric modeling technique able to manage all the geometrical parameters of the anisogrid composite lattice structure. Additionally, the genetic algorithm NSGA-II is employed to set up an optimization procedure which allows to analyze different sets of geometrical variables, both continuous and discrete, to reach the optimal solution in terms of mass amount and fulfilling of structural and stiffness requirements, aiming at the preliminary design of an actual structure. Numerical case-studies are outlined in order to demonstrate the practical usefulness and versatility of the proposed procedure to industrial cases where the anisogrid lattice conical structure undergoes multiple external loads and various stiffness constraints must be satisfied.

      PubDate: 2018-06-09T08:21:35Z
  • Fiber reinforced composites sandwich panels with web reinforced wood core
           for building floor applications
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Dian Zhu, Huiyuan Shi, Hai Fang, Weiqing Liu, Yujun Qi, Yu Bai
      The bending behavior of an innovative fiber reinforced polymer (FRP) sandwich panel was investigated for application in a multistory building. The panels featured a paulownia wood core reinforced by glass fiber reinforced polymer (GFRP) facesheets and web and was manufactured by a vacuum assisted resin infusion process. Specimens with different web thickness, web spacing, height, and facesheet thickness were loaded under four-point bending to validate the effectiveness of the detailed web configuration in improving panel stiffness and capacity. The results showed that the bending stiffness and ultimate bending strength could be enhanced by increasing the web thickness, web height, and facesheet thickness, as well as by reducing web spacing. An theoretical model based on Timoshenko beam theory was proposed to predict the bending stiffness and ultimate strength of the sandwich specimens. Furthermore, finite element analysis was established to verify the influences of web height, thickness, spacing, and facesheets on the GFRP floor panel performance. The theoretical results showed good agreement with the numerical and experimental results in terms of stiffness and ultimate bending strength. This work therefore assists the design of a multistory building completed with the proposed sandwich panel as the floor system.

      PubDate: 2018-06-09T08:21:35Z
  • Vibration-based identification of mechanical properties of orthotropic
           arbitrarily shaped plates: Numerical and experimental assessment
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): G. Battaglia, A. Di Matteo, G. Micale, A. Pirrotta
      An innovative procedure is introduced for the identification of the mechanical parameters of orthotropic plates of arbitrary shape, under various boundary conditions, based on vibration data. The method employs a combination of a convenient Rayleigh-Ritz approach and Particle-Swarm Optimization to estimate elastic constants of the orthotropic material in a straightforward manner, without requiring computationally demanding iterative Finite Element analyses. Specifically, the pb-2 Rayleigh-Ritz procedure is extended and applied to deal with orthotropic plates, simplifying the approach to more easily treat generic plate shapes, taking advantage of the Green's theorem. The method is then appropriately combined with the Particle-Swarm Optimization procedure to expeditiously identify material parameters based on available vibration data. Several numerical applications are presented to show the reliability of the approach, and comparisons with pertinent results available in the literature demonstrate the efficiency and accuracy of the proposed procedure. The study is then supplemented by experimental tests developed in the Laboratory of Experimental Dynamics at the University of Palermo, Italy. In this context, because of the obvious relevance for modern additive manufacturing processes, vibration tests are performed on several 3D printed stiffened plates. Numerical vis-à-vis experimental data are examined, showing that the proposed procedure accurately capture equivalent orthotropic parameters of the stiffened plates.

      PubDate: 2018-06-09T08:21:35Z
  • Facile synthesis of porous CuCo2O4 composite sheets and their
           supercapacitive performance
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Ashok Kumar Das, Nam Hoon Kim, Seung Hee Lee, Youngku Sohn, Joong Hee Lee
      The synthesis of metal oxide composites with porous structures for supercapacitor application has drawn much attention owing to their high surface area and easy access of the electrolyte ions to the electrode surface through the pores of the active materials. A facile hydrothermal approach is suggested for the synthesis of porous CuCo2O4 composite sheets and their application as an active electrode material for supercapacitor application. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) measurements show the formation of porous CuCo2O4 composite sheets. BET surface area measurements show that the porous CuCo2O4 composite sheet has 69.44 m2 g−1 surface area, which is 4.7 times higher than quasi-spherical CuCo2O4 nanoparticles. The porous CuCo2O4 composite sheet delivered 1037 C g−1 specific capacity at 5 mV s−1. Additionally, the porous CuCo2O4 composite sheet retained 94% of its initial specific capacity after 5000 charge-discharge cycles at 10 A g−1 indicating an excellent cyclic stability. This excellent supercapacitive performance is attributed to the high surface area and enhanced ion transport through the pores of the CuCo2O4 sheets. This high specific capacity and excellent cyclic stability of the porous CuCo2O4 composite sheets prove to be a promising candidate for supercapacitor application.
      Graphical abstract image

      PubDate: 2018-06-09T08:21:35Z
  • Thermally conductive polymer composites and nanocomposites:
           Processing-structure-property relationships
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Siu N. Leung
      Rapid fabricating technology advancement in the computing and electronic industries has led to new challenges in thermal management of electronics. As significantly more components are being packed in a smaller footprint in micro-and-nano-electronics, the amount of heat being generated in them has dramatically increased. In this context, efficient thermal management is critical to maintain the performance and reliability of electronic devices. Furthermore, other emerging technologies, such as light emitting diodes, flexible and wearable electronics, as well as electric vehicles, demand novel thermally conductive materials with new attributes (e.g., light-weight and flexible). This review reports key research advancements in elucidating the processing-structure-property relationships of thermally conductive polymer composites and nanocomposites. The recent progresses in processing technologies to tailor the phase morphologies and microstructures of polymer composites and nanocomposites and thereby enhance their effective thermal conductivity are discussed in detail. Finally, this review concludes by summarizing the key developments in this research area and prospects.

      PubDate: 2018-06-06T07:55:34Z
  • Experimental and numerical investigation on the crashworthiness of a
           composite fuselage sub-floor support system
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): A. Riccio, A. Raimondo, F. Di Caprio, M. Fusco, P. Sanità
      In the present paper, advanced numerical methodologies have been adopted to investigate the structural behaviour of a composite subcomponent for aerospace applications subjected to quasi-static compression and dynamic loads. The analysed structural component, made of laminated carbon fibres reinforced polymers, is part of the floor support system in the cargo area of a commercial aircraft. The inter-laminar and intra-laminar damage onset and propagation has been preliminary monitored under a quasi-static compressive displacement application. Then, the effects on the structural integrity of two impact energy levels have been analysed: 42 J energy has been applied to study the dynamic behaviour in an elastic linear rate while 585 J energy has been considered to assess the crashworthiness behaviour. The adopted numerical model has been validated by comparisons between the numerical results and analytical mass-spring model results and experimental data in terms of stiffness, strain, and ultimate load. The simultaneous assessment of numerical results and experimental data has allowed to provide a comprehensive insight on the damage onset and propagation leading to the structural collapse of the investigated sub-floor support system.

      PubDate: 2018-06-06T07:55:34Z
  • Prediction of notched strength for cylindrical composites pipes under
           tensile loading conditions
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): H. Benyahia, M. Tarfaoui, A. El Moumen, D. Ouinas
      In this paper, an experimental study has been performed on thick, ±55° filament wound glass/epoxy tubes using quasi-static tests to examine their offshore applications. A new design for the experimental test is developed in which the end tabs and fixture system are made in a way that the stress concentration at the edges of the composite pipe can be reduced. Split disk uniaxial tensile test has been performed on composite pipes with 86 mm of the internal diameter and the thickness of 6.2 mm, in order to evaluate the mechanical properties and to quantify the effect of geometric non-linearities. These pipes can be subjected to different phenomena which can result in introducing a defect in the structure. Two types of pipe specimens are tested which include the composite with notch and the other without notches. The objective of the using a notched specimen is to examine the evolution of the damage and to study the mechanical properties as a function of this damage. The experimental results are described as the influence of the number and the size of notches on the mechanical behavior. These results have shown that the yield stress decreases and yield strain increase with increasing of the notch size and number. The evolution of damage showed that the presence of notches plays an unfavorable role in the integrity of the structure.

      PubDate: 2018-06-06T07:55:34Z
  • A novel pseudo-grain approach for the estimation of the elastic stress
           distributions within the matrix of short fiber-reinforced polymers
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Riccardo Pietrogrande, Paolo Andrea Carraro, Matthias De Monte, Marino Quaresimin
      The aim of the work is to provide a new methodology for the calculation of the linear elastic stress distributions within the matrix of a short fiber-reinforced Representative Volume Element (RVE) with misaligned fibers, without relying on complex algorithms for the generation and solution of the microstructure. For this purpose, a Pseudo-Grain approach is adopted, the novelty of which lies in the computation of local stress distributions through the analytical combination of numerical solutions from unidirectional (UD) grains that can be easily and quickly solved through commercial codes. The new approach consists in two steps: i) the application of Voigt boundary conditions to Finite Element (FE) models (grains) with fully aligned fibers and ii) the mathematical combination of the computed Stress Cumulative Distribution Functions (S-CDF) on the basis of the second-order Fiber Orientation Tensor (FOT) of the microstructure of interest. The latter can be generally derived from process simulations or experimental analyses. The method is validated by comparing the resulting stress fields with those calculated from actual RVEs with different fiber volume fractions, fiber aspect ratios and Fiber Orientation Tensors, showing a very good agreement.

      PubDate: 2018-06-06T07:55:34Z
  • A new approach for bending analysis of bilayer conical graphene panels
           considering nonlinear van der Waals force
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Shahriar Dastjerdi, Bekir Akgöz, Leila Yazdanparast
      In the present study, the effects of nonlinear van der Waals forces on the bending analysis of orthotropic bilayer conical graphene panels are investigated. In order to model the nano-sized panels, the first-order shear deformation shell theory is used to obtain the governing equations by applying energy method in nonlocal form. Semi-analytical polynomial method (SAPM) is utilized to solve the resulting nonlinear governing equations. Due to cover a wide range of geometric shapes, the geometry is considered as a conical panel, so the results can be simulated for cylindrical panels, annular sectors, and even rectangular plates. The van der Waals force between upper and lower layers of graphene panel is simulated by an extension spring with the linear and nonlinear stiffness. It is easy to obtain the results of single-layer panels by eliminating the van der Waals force, and also for macroscopic plates, with neglecting the nonlocal effects. Finally, the affecting parameters on the results are examined in detail such as the plate size, orthotropic effects of material, nonlocal effects, van der Waals force including its nonlinear term and various types of boundary conditions, even the free edges.

      PubDate: 2018-06-06T07:55:34Z
  • Free vibration analysis of axially functionally graded tapered, stepped,
           and continuously segmented rods and beams
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Slaviša Šalinić, Aleksandar Obradović, Aleksandar Tomović
      In this paper a new non-iterative computational technique referred to as the symbolic-numeric method of initial parameters (SNMIP) is proposed. The SNMIP represents a modification of the iterative numeric method of initial parameters in differential form known in the literature. The SNMIP is applied to study free vibrations of Euler-Bernoulli axially functionally graded tapered, stepped, and continuously segmented rods and beams with elastically restrained end with attached masses. Both the longitudinal vibration of rods and transverse vibration of beams are considered. The influence of the attached masses and springs on the natural frequencies of vibration of axially functionally graded rods and beams is examined. The validity and accuracy of the method are proven through the comparison with the known results in the available literature.

      PubDate: 2018-06-06T07:55:34Z
  • Multi-scale wave propagation modelling for two-dimensional periodic
           textile composites
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): V. Thierry, L. Brown, D. Chronopoulos
      In this article, a method allowing vibro-acoustic and ultrasonic wave propagation analysis of highly anisotropic textile composites at a mesoscopic level is presented for the first time. The method combines the advantages of mode-based Component Mode Synthesis (CMS) that allows reduction of the size of the Dynamic Stiffness Matrix (DSM) of a textile unit cell, and of a Wave Finite Element Method (WFEM), which associates the Periodic Structure Theory (PST) with standard Finite Element Method (FEM). The scheme presented allows the study of the wave propagation properties of a periodic structure by modelling only a unit cell. A multi-scale approach is used to enable the comparison of standard vibrational analysis of textile composite structures, using homogenised properties, with a more complex analysis, where the mesoscale properties of the structure are preserved. It is shown for two different types of weaves that using a standard homogenised model results in significant errors in the dispersion curves. Also band-gap behaviour within specific frequency ranges are successfully predicted using the mesoscale models, whereas it was not observed in the macroscale ones.

      PubDate: 2018-06-06T07:55:34Z
  • Hygrothermal viscoelastic material characterisation of unidirectional
           continuous carbon-fibre reinforced polyamide 6
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Y.L.M. van Dijk, T. Grätzl, M. Abouhamzeh, L. Kroll, S. Shroff
      This paper presents results of material characterisation experiments on the hygrothermal viscoelastic behaviour of unidirectional laminates of continuous carbon-fibre reinforced polyamide 6. The material behaviour when subjected to the automotive painting process is of interest. Coefficients of thermal- and -moisture expansion were determined from dilatometer experiments and micrometer measurements together with weighing, respectively. Diffusion coefficients were generated from thermogravimetric analysis and fitted with the Arrhenius equation. Dynamic mechanical analysis and digital image correlation of quasi-static tensile tests were performed to obtain a relaxation curve and a major Poisson's ratio, respectively. The Williams-Landel-Ferry equation was fitted to the time shift factors.

      PubDate: 2018-06-06T07:55:34Z
  • What are the key parameters to produce a high-grade bio-based
           composite' Application to flax/epoxy UD laminates produced by
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Thomas Cadu, Michael Berges, Olivier Sicot, Véronique Person, Benoit Piezel, Laetitia Van Schoors, Vincent Placet, Stéphane Corn, Romain Léger, Loïc Divet, Patrick Ienny, Stéphane Fontaine
      The development of composites based on vegetal fibers requires a good control of manufacturing process. The aim of this work is to determine the key parameters to produce high grade flax/epoxy unidirectional laminated composite by thermocompression. So, many processing parameters have been tested and ranked according to their influence on mechanical properties. Since variability can be high for this kind of materials, statistical analyses have been used to determine if properties variations were significant or not. Among all studied parameters, the three which have been identified as first rank influence on mechanical properties are: fibers conditioning, curing pressure and exit plate temperature.

      PubDate: 2018-06-03T07:42:22Z
  • Experimental study on fatigue performance of adhesively bonded anchorage
           system for CFRP tendons
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Gui-hua Xie, Yong-sheng Tang, C.M. Wang, Shi-quan Li, Rong-gui Liu
      This study is concerned with the fatigue performance of adhesively bonded anchorage for carbon fiber reinforced polymer (CFRP) tendons subjected to cyclic loading. Series of monotonous and cyclic experiments under different stress amplitudes and loading frequencies were carried out in order to investigate the mechanical performance of bonded anchorage systems for CFRP tendons and to study the influence of cyclic loading on the anchoring performance. The fatigue damage and the relationships between damage, loading frequency and interfacial temperature rise of anchorage systems were analyzed. The results show that cyclic tension-tension loading is instrumental in enhancing the synergistic interaction between the anchorage components and it also stabilizes the entire anchorage system performance provided that the stress amplitude is kept lower than 10% of the ultimate tensile capacity of the anchorage systems and the maximum stress is less than 50% of the ultimate capacity of the anchorage system. The loading frequency influences significantly the temperature variation in the anchorage system. A high loading frequency may result in a sharp temperature rise at the early-stage and mid-stage of cyclic tension-tension loading, followed by a rather stable late stage. This phenomenon of temperature rise during fatigue tests may indicate the extent of fatigue damage in the anchorage system.

      PubDate: 2018-06-03T07:42:22Z
  • Facile preparation of reduced graphene oxide/copper sulfide composite as
           electrode materials for supercapacitors with high energy density
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Tingkai Zhao, Wenbo Yang, Xin Zhao, Xiarong Peng, Jingtian Hu, Chen Tang, Tiehu Li
      Recently, copper sulfide (CuS) quite arouses researchers' interest due to its high theoretical capacity and excellent electroconductivity. However, poor cycling stability seriously limited the application in supercapacitors. In addition to the improvement of cycling performance, it is also a challenge to develop electrode materials with energy density. Herein, RGO/CuS composite is prepared successfully by solvothermal reaction methods. By the observation using FESEM and TEM, CuS microstructure displays regular and tiny nanoparticles, which are supported by RGO sheets. After the electrochemical measurements, RGO/CuS composite exhibits a maximum specific capacitance of 946 F g−1 at 10 mV s−1 and 906 F g−1 at 1 A g−1, respectively. The excellent cycling stability is also achieved and it maintains 89% retention after 5000 cycles at 5 A g−1. RGO/CuS composite also possesses high energy density of 105.6 W h kg−1 at the power density of 2.5 kW kg−1, which indicates that RGO/CuS composite has a bright future as electrode materials for supercapacitors.

      PubDate: 2018-06-03T07:42:22Z
  • Vibrational characteristics of embedded microbeams lying on a
           two-parameter elastic foundation in thermal environment
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Bekir Akgöz, Ömer Civalek
      In the present work, thermo-elastic vibrational behavior of thick microbeams embedded in a two-parameter elastic foundation is studied. A Winkler-Pasternak type elastic foundation model is employed to simulate the interactions between microbeam and elastic medium. Size-dependent constitutive equations and associated boundary conditions are obtained by applying dynamic version of virtual work's principle based on modified couple stress and various beam theories. Several numerical examples are presented to examine the sensibility of various parameters associated with slenderness ratio, temperature rise, length scale, Winkler and shear layer parameters on the natural frequencies and critical temperature point of embedded microbeams.

      PubDate: 2018-06-03T07:42:22Z
  • Sustainable nanocomposites of epoxy and silica xerogel synthesized from
           corn stalk ash: Enhanced thermal and acoustic insulation performance
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Gulcihan Guzel Kaya, Elif Yilmaz, Huseyin Deveci
      The synthesis of silica xerogel from corn stalk ash in ambient pressure drying was carried out by sol-gel method. With the usage of silica xerogel (0.5, 1.0 and 1.5 wt%) in epoxy resin (ER), silica xerogel/epoxy nanocomposites were successfully prepared. The uniform dispersion of silica xerogel in neat ER was observed except nanocomposite including 1.5 wt% silica xerogel. The low density nanocomposites showed high thermal stability and low thermal conductivity. The char residue at 600 °C and thermal conductivity of nanocomposite including 1.5 wt% silica xerogel were specified as 20.30% and 0.220 W/mK, respectively. The acoustic velocity of the nanocomposites was decreased with increasing amount of silica xerogel. The water sorption of the nanocomposites was slightly higher than neat ER. The water contact angle of the nanocomposites were between 75° and 70°. The study provided a new thermal and acoustic insulation material instead of expensive and health risk traditional materials.
      Graphical abstract image

      PubDate: 2018-05-31T07:35:09Z
  • Plastic deformation mechanisms in severely strained eutectic high entropy
           composites explained via strain rate sensitivity and activation volume
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): T. Maity, K.G. Prashanth, Ö. Balçi, Z. Wang, Y.D. Jia, J. Eckert
      Eutectic high entropy composites (EHECs) are novel class of material with excellent combination of strength and ductility, thus having a large potential for industrial applications. However, the mechanisms operating behind the trade-off between strength and ductility has not been investigated in detail. In this work, the influence of severe straining imposed by high-pressure torsion (HPT) was evaluated for a series of CoCrFeNiNb x alloys with varying Nb content (x molar ratio), hypoeutectic (x = 0.25), eutectic (x = 0.65) and hypereutectic (x = 0.80) compositions. Strain rate sensitivity (m) and activation volume (V *) calculations were calculated from constant strain rate (CSR) nanoindentation experiments, revealing that dislocation interaction with lamellae interfaces become the rate-limiting step for the strength-ductility trade-off in these EHECs.

      PubDate: 2018-05-31T07:35:09Z
  • Experimental investigation on out-of-plane behavior of masonry panels
           strengthened with CFRP sheets
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Mario Fagone, Giovanna Ranocchiai
      The use of composite materials, in particular Carbon Fibre Composite Materials (CFRP), as reinforcement of both concrete and masonry structures is more and more widespread in the structural rehabilitation and retrofitting of existing buildings, thanks to their excellent mechanical performance combined with lightness and simplicity of application. Since the bond capacity of CFRP-to-masonry bonded joints, with respect to in-plane loads, is generally lower than the composite tensile strength, several methods have been proposed in the literature to increase their structural performance. Among these, CFRP spike anchors showed to be able to effectively increase strength and dissipative capability of CFRP reinforcement sheets. Nevertheless, their use in technical practice is discouraged by the lack of specific rules that adequately support designers. The development of predictive formulas, appearing necessary to bridge this gap, requires an extensive experimental database that highlights the peculiar characteristics of these reinforcements. As a contribution in this field, this paper presents an experimental program concerning the analysis of the mechanical behavior of this type of reinforcements applied to masonry structural elements loaded by out-of-plane actions. The experimental results showed that the effectiveness of such anchors strongly depends on the shape ratio of the specimens.

      PubDate: 2018-05-31T07:35:09Z
  • Local stress in periodic composites via the Riesz summability method
    • Abstract: Publication date: 1 October 2018
      Source:Composites Part B: Engineering, Volume 150
      Author(s): Andrea Caporale, Raimondo Luciano, Carlo Maria Medaglia, Rosa Penna
      Different summation methods of multidimensional trigonometric Fourier series are adopted for approximating the local strain and stress in elastic periodic composites. In fact, approximating the exact solution of a problem with the original partial sums of Fourier series can produce unwanted effects, such as the Gibbs phenomenon at the jump discontinuities that may occur at the interface between the constituents of the composites. Nevertheless, the Fourier coefficients of the original partial sums contain enough information to provide better estimates via the summability methods. In the means provided by the summability methods, the Fourier coefficients are suitably weighted by reducing windows, involving a regularization of the numerical solution. First, a complete solution method is used in order to determine some Fourier coefficients of the local strain in periodic composites. Next, these Fourier coefficients are used to construct suitable summations and means exhibiting better convergence properties than those of the original partial sums of Fourier series. The proposed method, valid for a great variety of the geometry of the constituents embedded in the matrix, is here applied to unidirectional composites with cylindrical fibers. The behavior of the iterated Fejér partial sums, Fejér and Riesz means is investigated in order to improve the convergence, observing that the Riesz means have better convergence properties than those of the original partial sums of Fourier series.

      PubDate: 2018-05-31T07:35:09Z
  • Effects of hydrazine reduced graphene oxide on the inter-laminar fracture
           toughness of woven carbon fiber/epoxy composite
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Nitai Chandra Adak, Suman Chhetri, Tapas Kuila, Naresh Chandra Murmu, Pranab Samanta, Joong Hee Lee
      In this work, the hybridization effects of hydrazine reduced graphene oxide (rGO) on the inter-laminar shear strength (ILSS), impact strength, and in-plane fracture toughness of symmetric type carbon fiber/epoxy composite (CF/epoxy) laminates were investigated. The composite laminates were fabricated through the vacuum-assisted resin transfer molding (VARTM) process. At 0.2 wt% of rGO loading, the CF/epoxy composites showed the best load carrying capacity among the developed laminates. ILSS, impact strength, and critical stress intensity factor (K IC ) were enhanced by ∼ (84, 100, and 33) %, respectively, in the case of rGO (0.2 wt%) filled CF/epoxy composite specimens, as compared to CF/epoxy composite. The consumed fracture energy of rGO (0.2 wt%)/CF/epoxy increased, as compared to the rGO (0.4 wt%)/CF/epoxy composite. The fracture surfaces obtained from field emission scanning electron microscopy of the developed composites showed compatible dispersion of rGO in the epoxy matrix, and branched fracture of the specimens. This study suggests that the rGO nanofiller might be used as a matrix modifier to resist matrix fracture, as well as fiber fracture.

      PubDate: 2018-05-28T09:01:18Z
  • High sensitive damage sensors based on the use of functionalized graphene
           nanoplatelets coated fabrics as reinforcement in multiscale composite
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Rocío Moriche, Alberto Jiménez-Suárez, María Sánchez, Silvia G. Prolongo, Alejandro Ureña
      Functionalized graphene nanoplatelets networks created through glass fiber fabrics were used to detect and locate damage in multiscale composite materials. The electrical behavior of multiscale composite materials was strongly influenced by microstructural features. Coated fabrics presented high sensitivity to breakage of fibers due to the preferential orientation of f-GNPs through fibers. This sensitivity was higher when damage was induced perpendicular to the fiber direction and the region where damage could be detected was bigger in the case of locating the measuring electrical channels perpendicular to fiber direction. These phenomena are related again to the morphology of the electrical network through the coating. Due to the insulating character through thickness of composites, detection and location was limited to layers of fabric of the composite. Nevertheless, self-sensors had the capacity of detecting and locating damage with high sensitivity by means of abrupt increases in electrical resistance induced by breakage.

      PubDate: 2018-05-28T09:01:18Z
  • Experimental and statistical analysis of low velocity impact response of
           filament wound composite pipes
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Lokman Gemi, Mehmet Kayrıcı, Muhammet Uludağ, Dilek Soylu Gemi, Ömer Sinan Şahin
      Nowadays, filament wound composite pipes (GRP) are used as a structural element in many applications such as natural gas and oil transmission lines, and portable bridge constructions for military purposes. GRP pipes can expose to impact loading from various causes. This loading can cause an invisible level of damage. Thus, the detection and evaluation of such damages are of great importance. In this study, the low velocity impact response of (±55°)3 filament wound E-glass/epoxy composite pipes has been studied. The pipes have been subjected to drop weight impact loading with various impact energies. The force-time and force-displacement relations have been examined. The impact damage formation was also evaluated. It is concluded that the damage development in the pipes is controlled by displacement trough radial direction. The obtained results were evaluated statistically by means of Weibull approach. Microscopy analysis of impacted region revealed that debonding, radial cracks, transfer cracks and delamination damage modes are the main observed damage modes.

      PubDate: 2018-05-28T09:01:18Z
  • Micromechanics of kink band formation in open-hole fibre composites under
           compressive loading
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Vedad Tojaga, Simon P.H. Skovsgaard, Henrik Myhre Jensen
      The micromechanics of kink band formation in open-hole fibre composites under compressive loading is described. The objective being the development of a methodology for designing of structural components with open-holes. Our results explain why failure by kink band formation propagates from the edges of an open-hole in a direction almost perpendicular to the loading direction and why the 0 plies govern the compressive failure of an open-hole laminate. The proposed design methodology accounts for the microstructure, including the fibre/matrix bonding, and the nonlinear behaviour of the constituents, enabling it to prevent local failure at the hole edges, or global failure, by kink banding of a laminate containing stress concentrations.

      PubDate: 2018-05-28T09:01:18Z
  • Influence of phenylphosphonic amide on rheological, mechanical and
           flammable properties of carbon fiber/RTM6 composites
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Xiaomin Zhao, Lu Zhang, Juan Picón Alonso, Sofía Delgado, M.R. Martínez-Miranda, De-Yi Wang
      The aim of this work was to study the influence of a high efficient halogen-free phenylphosphonic amide flame retardant (FP1) to epoxy resin (brand name RTM6) on the rheological, mechanical and water absorption properties of the carbon fiber/RTM6 epoxy composite (CFR). With a 8 wt% loading FP1 in RMT6, the processing of CFR/FP1 was able to use the equal condition with that of CFR since the viscosity of RTM6 was maintained at a similar level in the minimum viscosity temperature region. The addition of FP1 showed negligible impacts on the interlayer share strength (ILSS) and in-plane share strength (IPSS) of CFR. The interfacial strength between RTM6 matrix and carbon fiber was decreased due to the impact of FP1 on cross-linking density and polarity of RTM6. The flame retardant efficiency of FP1 showed difference in presence of carbon fiber or not in RTM6. RTM6/FP1 (8 wt%) had a LOI value of 38%, achieved a V-0 rating at thickness of 3.2 mm in UL 94 test and showed 60% reduction in peak of heat release rate. RTM6/carbon fiber/FP1 (8 wt%) had a LOI of 43%, while it showed reduced performance in UL 94 and cone calorimeter tests.

      PubDate: 2018-05-28T09:01:18Z
  • Strengthening of RC beams using bottom and side NSM reinforcement
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Cristian Sabau, Cosmin Popescu, Gabriel Sas, Jacob Wittrup Schmidt, Thomas Blanksvärd, Björn Täljsten
      The allowable strain in fibre reinforced polymers reinforcement is limited by design codes to avoid debonding. The near-surface mounted (NSM) reinforcement technique has been proven to produce better anchorage behaviour compared to externally bonded reinforcement solutions. However, NSM solutions do not always eliminate debonding issues, with concrete cover detachment (CCD) typically occurring in RC beams strengthened for flexure. This experimental study investigated the efficiency of side mounted (S) compared to bottom mounted (B) NSM bars to prevent CCD. The experimental results were compared to models available in the literature that predict the observed failure modes and the crack spacing in the NSM anchorage zone. Compared to B-NSM, the S-NSM solution was successful in avoiding brittle CCD failure and showed increased rotational capacity and energy dissipation at failure. Existing CCD debonding models were found to be conservative.

      PubDate: 2018-05-28T09:01:18Z
  • Synthesis and growth mechanism of various SiO2 nanostructures from
           straight to helical morphologies
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Wei Tian, Siyan Liu, Longjiang Deng, Nasir Mahmood, Xian Jian
      Taking into account the high demands and applications of amorphous SiO2 in various nanostructured forms, here we have synthesized various nanostructures of SiO2 including nanosprings, straight nanofibers, nanotubes and nanobelts. A simple catalytic chemical vapor deposition (CCVD) technique is developed where Si, SiO2 and graphene capsules are utilized as starting materials. The structural and chemical analysis of the as-prepared nanostructures confirms the amorphous nature of SiO2 and shows the minor existence of SiC, which acts as a growth directing agent for various shapes of SiO2. The electron microscopic observations delineate the morphologies of the as-prepared nanostructures with different shapes i.e. nano-fibers, tubes, springs and belts. It is observed that straight SiO2 fibers having diameter of ∼440 nm are thicker than the fibers (∼220 nm) constructing the nanosprings while the overall helical diameter falls in the range of 530–690 nm. The in-depth structural and morphological studies reveal that the growth mechanism of SiO2 nanostructures is in the vapor-liquid-solid (VLS) growth mode. The unique microstructures with special morphologies straight, helical and hollow shapes make them potential candidate for several functional applications such as nanoelectron-magnetic devices, mechanical sensor system and flexible energy storage devices.

      PubDate: 2018-05-28T09:01:18Z
  • Dynamic responses of aerothermoelastic functionally graded CNT reinforced
           composite panels in supersonic airflow subjected to low-velocity impact
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Z.G. Song, X. He, K.M. Liew
      The low-velocity impact behaviors of aeroelastic functionally graded CNT (carbon nanotube) reinforced composite panels in supersonic airflow are investigated. Thermal effects are taken into account. Reddy's higher-order shear deformation theory is applied in the structural modeling. The effective material properties of the functionally graded CNT reinforced composite panel are calculated by the rule of mixture. The aerodynamic pressure is evaluated by the first-order piston theory. The contact force between the panel and the impactor is simulated by the Hertz law. Hamilton's principle and the assumed modes method are used to formulate the equation of motion which is then solved by the numerical method because of the high nonlinearity. A simplified mass-damping-spring model is also introduced to solve the problem. Influences of the aerodynamic pressure, CNTs distribution and volume fraction and thermal effects on the impact responses of the functionally graded CNT reinforced composite panels are investigated. The simulating results using the numerical model and the mass-damping-spring model are compared. The affect factor considering the inertial effect of the panel in the low-velocity impact for the CNT reinforced composite panel is given out.

      PubDate: 2018-05-28T09:01:18Z
  • 3D particle models for composite laminates with anisotropic elasticity
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Lei Wan, Dongmin Yang, Yaser Ismail, Yong Sheng
      This paper presents an assessment of three different particle based approaches for 3D modelling of fibre reinforced polymer (FRP) composite laminates with anisotropic elasticity, namely 3D Discrete Lattice model, 3D Hexagonal Close Packing model and Extended 2D Hexagonal and Square Packing model. These approaches are compared and evaluated against experimental results using a 0 ∘ ply lamina case. It has been confirmed that the Extended 2D Hexagonal and Square modelling approach in Discrete Element Method (DEM) is capable of modelling 3D composite laminates with better efficiency. Angle-ply lamina and two different laminates are modelled with the chosen particle approach. Good agreements between DEM, Finite Element and theoretical results prove the capability of this developed DEM approach for modelling the elastic behaviour of general FRP composite lamina and laminates.

      PubDate: 2018-05-28T09:01:18Z
  • Effect of multiscale reinforcement on the mechanical properties and
           microstructure of microcrystalline cellulose-carbon nanotube reinforced
           cementitious composites
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Ahmad Alshaghel, Shama Parveen, Sohel Rana, Raul Fangueiro
      The present research investigated for the first time the combined effect of microcrystalline cellulose (MCC) and carbon nanotube (CNT) on the performance of cement composites. Multi-scale or hierarchical composites were developed by dispersing MCC and multi-wall CNT (MWCNT) within the cementitious matrix as reinforcements. Homogeneous suspensions of MCC (0.4 wt% and 1 wt%) and CNTs (0.2 wt% and 0.6 wt%) in water were prepared using two different surfactants, cetyltrimethylammoniumbromide (CTAB) and Pluronic F-127 using ultrasonication energy, and the suspensions were subsequently added to cement-sand mixture to fabricate cementitious composites. The composite samples were stored in water for 28 and 56 days to carry out the hydration process and were next characterized for flexural and compressive properties, dry bulk density, porosity, hydration products and fracture surface morphology. It was observed that the flexural and compressive strengths of cement composites improved significantly due to the MCC - CNT hybrid reinforcement. The highest improvements in flexural strength of 12.3% and 23.2% and compressive strength of 16.3% and 27.9% were achieved with 0.5 wt % MCC-0.3 wt % CNT in 28 and 56 days, respectively. In addition, significant improvements in flexural modulus, flexural strain and fracture energy were also noticed. Positive influence of hybrid reinforcement on the porosity of cementitious composites was also confirmed; the average pore diameter of plain mortar reduced from 47.5 nm to 30 nm. Further, the multi-scale composites exhibited higher bulk density, better hydration and crack bridging by CNTs leading to higher fracture energy.

      PubDate: 2018-05-28T09:01:18Z
  • Mechanical performance of epoxy coated AR-glass fabric Textile Reinforced
           Mortar: Influence of coating thickness and formulation
    • Abstract: Publication date: 15 September 2018
      Source:Composites Part B: Engineering, Volume 149
      Author(s): Massimo Messori, Andrea Nobili, Cesare Signorini, Antonella Sola
      The mechanical performance of epoxy coated AR-glass fabric reinforced composite is investigated. A three-stage manufacturing process is considered, which involves fabric surface functionalization, liquid coating deposition and long-term setting and finally fabric embedment in the mortar matrix. Two epoxy coatings are considered, which only differ by the hardening agent. However, coating thickness is significantly diverse as a result of modified viscosity during liquid deposition. Performance is assessed in uni-axial tension as well as in three-point bending and it is expressed in terms of strength curves, data dispersion, crack pattern and failure mechanism. Remarkably, despite being very similar, the analyzed coatings produce a significantly different performance, especially when data dispersion is incorporated and design limits are considered. Indeed, although both coatings are able to consistently deliver fabric rupture at failure, only the thinnest is associated with small data scattering and an almost plastic post-peak behavior in bending. The associated design elongation limit reaches the maximum allowed value according to the ICC guidelines. In fact, it appears that coating thickness plays a crucial role in determining mechanical performance and fabric flexibility. The proposed manufacturing process proves extremely effective at enhancing matrix-to-fabric adhesion and thereby prevent telescopic failure.

      PubDate: 2018-05-28T09:01:18Z
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Heriot-Watt University
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