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  Subjects -> ENGINEERING (Total: 2284 journals)
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ENGINEERING (1208 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 6)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 229)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
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: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 25)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 29)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arid Zone Journal of Engineering, Technology and Environment     Open Access   (Followers: 2)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
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: 8)
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: 4)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
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: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 3)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 3)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 254)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 181)
Composites Part B : Engineering     Hybrid Journal   (Followers: 227)
Composites Science and Technology     Hybrid Journal   (Followers: 184)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 13)
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: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  

        1 2 3 4 5 6 7 | Last

Journal Cover Composites Part A : Applied Science and Manufacturing
  [SJR: 1.599]   [H-I: 113]   [181 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1359-835X
   Published by Elsevier Homepage  [3042 journals]
  • Facile synthesis of three-dimensional (3D) interconnecting polypyrrole
           (PPy) nanowires/nanofibrous textile composite electrode for high
           performance supercapacitors
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Qiongzhen Liu, Bo Wang, Jiahui Chen, Fei Li, Ke Liu, Yuedan Wang, Mufang Li, Zhentan Lu, Wenwen Wang, Dong Wang
      In present work, polypyrrole (PPy) has been in-situ polymerized on a poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofirous textile to form a 3D interconnecting PPy nanowires/nanofibrous textile composite electrode (designated as NW-PPy/NFs/PET). It demonstrates that the introduction of anthraquinone-2-sulfonic acid sodium (AQS) can tune the morphology of PPy from nanospheres to nanowires. The resulting PPy@PVA-co-PE conformal nanofibers act as bridges among intertwined PPy@PET fibers and PPy nanowires, leading to continuous pathways for ion/electron transfer and larger surface area for faradic reaction. Benefiting from this unique structure, the two-electrode supercapacitor using NaCl solution as electrolyte delivers a high power density of 800Wkg−1 at an energy density of 20Whkg−1 per mass of active materials. Furthermore, the symmetric all-solid-state NW-PPy/NFs/PET supercapacitor demonstrates high flexibility and cycle stability. Therefore, this work may open a new way to develop light weight and cost-effective electrodes for flexible energy storage devices.

      PubDate: 2017-07-23T23:59:46Z
  • Flexible hdC-G reinforced polyimide composites with high dielectric
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Xiaojian Liao, Wan Ye, Linlin Chen, Shaohua Jiang, Guan Wang, Lin Zhang, Haoqing Hou
      Carbon nanotubes (CNTs) reinforced composites with high dielectric permittivity empower miscellaneous applications in flexible electronics but are hindered by the large addition and agglomeration of fillers and weak mechanical performance. Here, we prepare homogeneous dispersion of CNTs and graphene oxide (hdC-G) via solvent-exchange, and fabricate hdC-G/polyimide (PI) composite films by in situ polymerization and thermal imidization. The achieved hdC-G can construct a 3D network and keep a long term stability. The hdC-G/PI composites show high dielectric permittivity of 124.9 at 100Hz, 4000% higher than that of pure PI. The hdC-G/PI composites also exhibit enhanced thermal stability and improved tensile strength without sacrificing the flexibility. This solvent-exchange approach can greatly enrich the applications of synergistic uses of CNTs and GO in composites and the hdC-G/PI composites with simultaneously high dielectric permittivity, low content of fillers, good mechanical and thermal performances can be good candidates for flexible electronics.

      PubDate: 2017-07-23T23:59:46Z
  • Pre-impregnated natural fibre-thermoplastic composite tape manufacture
           using a novel process
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): O.P.L. McGregor, M. Duhovic, A.A. Somashekar, D. Bhattacharyya
      Pre-impregnated flax and thermoplastic poly(amide) composite tapes have been produced using a novel process. The manufacturing method uses an impregnation unit with a siphon system to impregnate continuous flax yarns with the polymer in the form of a slurry. After water evaporation, the powder is sintered and the coated yarns are compressed by passing them through a pair of heated rollers. Using a parametric study of the process, tape quality has been assured using the key outcome criteria of tensile strength/stiffness, surface roughness, fibre weight fraction, width and thickness. The temperature of the air heater placed before the roller has the biggest influence on tape quality. A heating model was developed using finite element software LS-DYNA. The research novelty comes from producing composite tapes with good tensile properties and surface finish using aligned natural fibres; the feasibility of automated tape placement and winding has also been demonstrated.

      PubDate: 2017-07-23T23:59:46Z
  • On the variability of mesoscale permeability of a 2/2 twill carbon fabric
           induced by variability of the internal geometry
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): M. Bodaghi, A. Vanaerschot, S.V. Lomov, N.C. Correia
      This paper incorporates geometric variability in the determination of permeability, using distributions and spatial correlations of yarn spacing, width and thickness and distortions of yarn centrelines. Variability of a 2/2-twill carbon fabric geometry over a region of ten-by-ten unit cells is characterized based on representation of the yarn path deviations using Markov chains and the correlations between the deviations in the neighbouring yarns using Series Expansion approach. The Stokes equation is solved for the generated stochastic unit cells to predict inter-yarn permeability of each unit cell in principal directions. There is a good agreement between the calculated mean permeability and the values in the Permeability Benchmark II. The predictions show permeability varies over the medium as a function of inter-yarn gaps. Permeability variations show a correlation length of circa 20mm, the size of two-unit cells. Permeability values in x direction have no evident correlation with those in y direction.

      PubDate: 2017-07-23T23:59:46Z
  • Heater power control for multi-material, variable speed Automated Fibre
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Mattia Di Francesco, Laura Veldenz, Giuseppe Dell'Anno, Kevin Potter
      Automated Fibre Placement requires accurate control of the heater power to deposit the material at appropriate temperatures throughout the process. This paper presents a simple semi-empirical thermal model of the process which correlates the heater power and the layup speed with the substrate surface temperature. The deposition temperature was measured over a range of heater powers and layup speeds. The experimental data is used to define and validate a semi-empirical thermal model for two classes of materials used in conjunction with a diode laser: carbon fibre reinforced thermoplastics and bindered dry fibres. This enables open-loop, speed dependent heater power control, based on defining and programming the speed dependent heater power function in the machine controls.

      PubDate: 2017-07-23T23:59:46Z
  • Lignocellulosic fiber breakage in a molten polymer. Part 3. Modeling of
           the dimensional change of the fibers during compounding by twin screw
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): F. Berzin, J. Beaugrand, S. Dobosz, T. Budtova, B. Vergnes
      In Part 1 and Part 2 of this series, models describing lignocellulose fiber breakage during melt mixing process have been established. In Part 3, these models are applied to predict fiber size when compounding composites in a twin-screw extruder. A comparison with the experimental values of fiber dimensions in composites made under different processing conditions is performed. Various types of fibers (flax, hemp and sisal) with different initial morphologies and sizes were considered in order to show the generality of the approach. First, experimental results, highlighting the main impact of processing parameters on the fiber dimensions, are presented. A particular interest was paid on the change of fiber length, diameter and aspect ratio (length/diameter) all along the screws. Then, it is shown how flow modeling can help to better interpret these results and lead to a predictive approach of fiber breakage during twin-screw extrusion, in order to optimize the compounding process.

      PubDate: 2017-07-23T23:59:46Z
  • Mechanisms and characterization of impact damage in 2D and 3D woven
           fiber-reinforced composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Kevin R. Hart, Patrick X.L. Chia, Lawrence E. Sheridan, Eric D. Wetzel, Nancy R. Sottos, Scott R. White
      Low velocity impact damage of 2D and 3D woven glass/epoxy composites with the same areal density and material constituents were examined. Characterization of damage for both plate and beam sample geometries was investigated through the collection of high-resolution cross-sectional images after impact. Load and displacement data collected during impact testing reveals that the threshold load to introduce delamination damage is independent of the fabric architecture and is constant across a range of impact energies. Delamination length and opening of 3D woven composites was less than 2D composites impacted at the same energy as a result of suppression of delamination propagation and opening offered by the Z-tow reinforcement of the 3D fabric architecture. The formation of transverse shear cracks was independent of the fabric architecture.

      PubDate: 2017-07-23T23:59:46Z
  • On the stochastic variations of intra-tow permeability induced by internal
           geometry variability in a 2/2 twill carbon fabric
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): M. Bodaghi, A. Vanaerschot, S. V. Lomov, N. C. Correia
      This study investigates the stochastic variation of tow cross sections in a 2/2 twill carbon fabric and intra-tow permeability. A large sampling of tow cross sections (720 per layer) done by X-ray Micro-Computed-Tomography of a 7-layer composite plate is used to validate the use of the following statistical distributions of the random geometrical parameters: tow thickness (normal), tow width (log-logistic), intra-tow fibre volume fraction (log-normal) – and intra-tow permeability (gamma). The intra-tow fibre volume fraction and permeability variables are auto-correlated with a correlation length of ca. 3mm, which corresponds to a correlation length of the out-of-plane tow centroid coordinates and is close to the spacing of the warp and weft yarns. The findings can serve as guidelines in doing Monte Carlo modelling of woven preforms variability and continue previously published work on inter-tow geometry and permeability.

      PubDate: 2017-07-23T23:59:46Z
  • Tensile behaviour of uncured sheet moulding compounds: Rheology and
           flow-induced microstructures
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): D. Ferré Sentis, T. Cochereau, L. Orgéas, P.J.J. Dumont, S. Rolland du Roscoat, T. Laurencin, M. Terrien, M. Sager
      During compression moulding, Sheet Moulding Compounds (SMCs) are subjected to tensile strains that yield detrimental tears. To understand these mechanisms, tensile experiments were performed with two uncured industrial SMC formulations with low and high pore and fibre contents. These experiments were coupled with Digital Image Correlation to estimate mesoscale strain fields on the sample surface. X-ray microtomography was used to obtain 3D ex situ evolutions of pores and fibre-bundle orientation. Both formulations behaved as porous, elastoviscoplastic, anisotropic and shear thinning fluids, showing strain hardening followed by softening and sample breakage. During stretching, SMCs dilated with anisotropic pore growth, whereas fibre bundles aligned along the tensile direction following the prediction of the modified Jeffery’s equation. In addition, the ductility of SMCs was largely altered both by the initial pore contents and fibre-bundle flocs/aggregates induced during the prepreg fabrication, the latter leading to undesirable strain localisation bands enhancing sample breakage.

      PubDate: 2017-07-23T23:59:46Z
  • Comparison of Compression-After-Impact and Flexure-After-Impact protocols
           for 2D and 3D woven fiber-reinforced composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Kevin R. Hart, Patrick X.L. Chia, Lawrence E. Sheridan, Eric D. Wetzel, Nancy R. Sottos, Scott R. White
      Post-impact mechanical response of 2D and 3D woven glass/epoxy composite plates and beams of equivalent areal density are evaluated using both Compression-After-Impact (CAI) and Flexure-After-Impact (FAI) testing protocols. Residual strength and stiffness for CAI and FAI are compared after normalization of impact energy with respect to specimen volume. Post-impact flexural strength and modulus from FAI testing exhibit larger reductions with respect to impact energy in comparison to CAI results. At the largest impact energies tested, FAI testing yields 70% reduction in flexural strength compared to only 20% reduction (in compressive strength). Architecturally, 3D woven composites retain greater post-impact mechanical performance as a result of the through-thickness Z-tow which suppresses delamination growth and opening during impact.

      PubDate: 2017-07-23T23:59:46Z
  • Synergic effects of cellulose nanocrystals and alkali on the mechanical
           properties of sisal fibers and their bonding properties with epoxy
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Zhongsen Zhang, Yan Li, Chaozhong Chen
      Cellulose nanocrystal (CNC), as a new promising nanomaterial, has attracted considerable attention in recent years. In this research, electrophoretic deposition (EPD) was employed to modify sisal fibers with CNCs. Sisal fibers were treated with alkali before CNCs were deposited on their surface. The synergic effects of alkali and CNCs on the mechanical properties of sisal fiber and its interfacial properties with epoxy resin over a range of temperatures were investigated. The results showed that a 62% increase in tensile modulus of sisal fibers was obtained. At room temperature, the CNCs coating did not show any obvious effect on the interfacial shear strength (IFSS) between sisal fiber and epoxy while changing the debonding mode with an increased debonding frictional force. In the case of being at elevated temperatures, the CNCs modification significantly reduced the inverse effect of temperature on IFSS owing to the formation of an interphase with improved thermo-mechanical stability.

      PubDate: 2017-07-23T23:59:46Z
  • Amino-terminated nitrogen-rich layer to improve the interlaminar shear
           strength between carbon fiber and a thermoplastic matrix
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Nan Li, Lishuai Zong, Zuoqiang Wu, Cheng Liu, Xin Wang, Feng Bao, Jinyan Wang, Xigao Jian
      An amino-terminated nitrogen-rich layer of poly(cyclotriphosphazene-co-melamine) (PPM) coating was used to functionalize carbon fiber (CF) to strengthen the interfacial adhesion of CF reinforced copoly(phthalazinone ether sulfone)s (PPBES) through a facile in-situ polymerization. FTIR, Raman and XPS confirm the chemical bonds between CF and PPM. SEM and dynamic contact angle tests demonstrate that PPM coating can enhance surface wettability, roughnes of CF, which can improve interlaminar shear strength and flexural strength of CF/PPBES by 23.2% and 29.3% with no discernable decrease on tensile strength of CFs. According to DMA test, storage modulus and service temperature increase by 15GPa and 6°C. SEM observations certify that the failure mechanism transforms from interface failure for CF/PPBES to matrix failure and fiber broken for CF-PPM/PPBES. Moreover, the successful preparation of PPM coatings on CF surface provides new insights for the fabrication of advanced thermoplastic composites from readily available components via a facile route.

      PubDate: 2017-07-23T23:59:46Z
  • Synthesis and characterization of novel phenolic resin/silicone hybrid
           aerogel composites with enhanced thermal, mechanical and ablative
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Rongying Yin, Haiming Cheng, Changqing Hong, Xinghong Zhang
      A novel lightweight phenolic resin/silicone (PR-Si) hybrid aerogel composite was fabricated through vacuum impregnation using PR-Si hybrid aerogels as matrix and low density (0.184g/cm3) carbon-bonded carbon fibre as 3-dimensional reinforcement. The PR-Si hybrid aerogels was synthesized through a facile sol-gel polymerization, accompanied by solvent exchange and ambient pressure drying from a mixture of PR and methyltrimethoxysilane (MTMS) with ethylene glycol as the porogen and hexamethylenetetramine as the catalyst. The hybrid aerogels possess hierarchically micro-meso-macroporous structure and higher thermal stability than that of the pristine PR aerogels. The obtained aerogel composites exhibit low density (0.312–0.356g/cm3), high compressive strength (0.76–4.08MPa), low thermal conductivity (0.098–0.240W/(mK)), and good thermal ablative and insulative properties in oxyacetylene flame simulated high temperature environment (linear ablation rates as low as 0.073mm/s and internal temperature peaks below 200°C at 38mm in-depth position as the surface temperature approximately 1800°C).

      PubDate: 2017-07-23T23:59:46Z
  • Grafting of size-controlled graphene oxide sheets onto carbon fiber for
           reinforcement of carbon fiber/epoxy composite interfacial strength
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Caifeng Wang, Jun Li, Jiali Yu, Shaofan Sun, Xiaoyu Li, Fei Xie, Bo Jiang, Guangshun Wu, Fei Yu, Yudong Huang
      It is widely accepted that the interfacial properties of carbon fiber (CF) reinforced composites tend to be weak due to the poor wettability and chemically inert surface of CF, which greatly limits the reinforcement effect of CF in composites. Here, size-controllable graphene oxide sheets (GO) were grafted on CF using Poly(oxypropylene) Diamines (D400) as the bridging agent to improve the interfacial properties of CF composites. It was found that the size and content of active functional groups on GO played important roles in controlling the surface morphology of GO grafted CF. Moreover, the interfacial shear strength (IFSS) of the middle sized GO sheets grafted CF/epoxy composites reached a maximum value of 82.2MPa, with an enhancement of 75.6% compared with untreated CF. That is to say, the strong mechanical interlocking between CF and epoxy resin and the improved wettability of resin on CF surface were responsible for the enhancement of IFSS. Instead of decaying of fiber tensile strength after treatment, the tensile strength of GO grafted CF increased from 4.73GPa to 5.02GPa. The reason for the enhancement may be due to that GO bridged the surface defects on CF. This hierarchical reinforcement was believed to have widely potential applications in high performance polymer matrix composites.

      PubDate: 2017-07-23T23:59:46Z
  • Effect of residual stress on the matrix fatigue cracking of rapidly cured
           epoxy/anhydride composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Mathew W. Joosten, Steven Agius, Tim Hilditch, Chun Wang
      There is an increasing demand for rapid cure resin systems for high-volume production of composite structures, especially for the automotive sector. While shortening production time, rapid cure cycles often lead to high residual thermal stresses in the structure. This study investigates the impact of residual stress on the onset of fatigue induced matrix micro-cracking in carbon-epoxy composites made of rapid curing resin. The effect of residual stress on the onset of fatigue induced matrix cracking was predicted using a simplified analytical model with the assumption of plane stress. A good agreement is observed between the analytical prediction and experimental results, however, further validation is required to assess the model’s potential in accelerating the design and certification of composite structures to meet fatigue endurance requirements.

      PubDate: 2017-07-23T23:59:46Z
  • Bio-inspired sandwich-structured carbon/silicon/titanium-oxide nanofibers
           composite as an anode material for lithium-ion batteries
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Dongling Jia, Xue Li, Jianguo Huang
      A bio-inspired sandwich-structured carbon/silicon/titanium-oxide nanofibers composite is fabricated based on the self-assembly technique by using cellulose substance as both the carbon source and the structural scaffold. It holds the hierarchical structure of the initial cellulose substance. And it is composed of thin silicon layer sandwiched between the carbon nanofiber and the outer titanium oxide coating layer consisting of anatase titania nanoparticles with oxygen defects. Owing to the synergetic effect of the porous carbon nanofiber and titanium oxide coating layer, as well as its unique three-dimensional network structure, this nanocomposite shows enhanced lithium storage properties. For the composite with 24.1wt% of titanium oxide, it delivers a stable reversible capacity of ca. 792.6mAhg−1 at a current density of 100mAg−1 after 160 discharge/charge cycles, which superiors to the nanofibrous silicon and carbon/silicon matters as well as the carbon/silicon/titanium-oxide composites with low titanium oxide content therein.
      Graphical abstract image

      PubDate: 2017-07-12T13:13:18Z
  • Prediction of size effects in open-hole laminates using only the Young’s
           modulus, the strength, and the R-curve of the 0° ply
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): C. Furtado, A. Arteiro, M.A. Bessa, B.L. Wardle, P.P. Camanho
      Advanced non-linear Finite Element models for the strength prediction of composite laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the laminate level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R -curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general laminates, and an analytical model to estimate the R -curve of balanced laminates. These laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.

      PubDate: 2017-07-12T13:13:18Z
  • Experimental and cohesive finite element investigation of interfacial
           behavior of CNT fiber-reinforced composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Dan Li, Qing-Sheng Yang, Xia Liu, Xiao-Qiao He
      The interfacial behavior of carbon nanotube fiber (CNT fiber) composites is studied by using an experiment of fiber pulling-out from a polymer microdroplet and cohesive finite element method. A clamping fixture based on nano-tensile test system was designed for the microdroplet test of interfacial properties of the composites. Force-displacement curves and shear strengths of the interface between CNT fibers and polymers were obtained. Then an experiment-based cohesive finite element model was established to simulate the debonding and slipping of interface between the CNT fiber and polymer. Calculated force-displacement curves for fiber pullout from microdroplet are comparable with the experimental data. The debonding strength and failure feature of the interface of CNT fiber composite were discussed. It is found that the looseness of CNT fiber assembled by CNT bundles and threads leads to relatively low interfacial strength, which is very different from the traditional continuum-block fiber composites.

      PubDate: 2017-07-12T13:13:18Z
  • High temperature ablation and thermo-physical properties improvement of
           carbon fiber reinforced composite using graphene oxide nanopowder
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Samire Sabagh, Ahmad Aref Azar, Ahmad Reza Bahramian
      Ablative nanocomposites were prepared by incorporating graphene oxide (GO) nanosheets into resole type phenolic resin and then impregnating them into rayon-based carbon fabric. GO were dispersed into phenolic resin at 0.25, 0.75, and 1.25wt.% loadings using high shear mixing to insure uniform GO dispersion. The morphology and structure of graphene oxide nanosheets (synthesized by a Hummers method) and the structural, thermal and ablative properties of the samples were characterized using Fourier Transform Infrared spectroscopy(FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), oxyacetylene flame test, and Thermo-Gravimetric Analysis (TGA) methods. It was found that the thermal stability and ablative properties of the GO/phenolic resin/carbon fiber composites were greatly enhanced due to the well dispersion of GO sheets in polymer matrix and the strong interfacial interaction between the GO sheets and phenolic matrix as well as layered carbon structure after pyrolysis. The specimen with 1.25wt.% GO showed the best results in the rate of ablation, thermal diffusivity and thermal stability compared to other samples. This laminate had constant thermal diffusivity at different temperatures, and improved char yield and ablation rate to about 10% and 51%, respectively.

      PubDate: 2017-07-12T13:13:18Z
  • Modelling the effect of process-induced anisotropy on the constitutive
           behavior of chopped fiber composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): N. Feld, C. Maeyens, B. Delattre, N. Grandmaison
      This study aims at understanding the influence of process-induced anisotropy on the mechanical behavior of chopped fiber composites up to the onset of failure. Due to the specific microstructure of these materials – neither laminates nor reinforced plastics – a new specimen geometry must be devised for their characterization. Experimental investigations coupled with full field analyses led to the definition of a geometry that avoids edge effects and minimizes strain heterogeneity along the free length. Specimens adopting this geometry were cut out of plates manufactured with a controlled process-induced anisotropy, in different directions. Monotonic and cycled loading paths were applied to these coupons and an elastic–plastic damageable behavior is observed, with little strain rate effects in quasi-statics. Both linear and nonlinear mechanisms display a significant anisotropy, which is found to evolve monotonously with process-induced strains. Simple scalar evolution laws for irreversible strains and loss of stiffness may nevertheless be identified.

      PubDate: 2017-07-12T13:13:18Z
  • Study of thermal conductivity and stress-strain compression behavior of
           epoxy composites highly filled with Al and Al/f-MWCNT obtained by
           high-energy ball milling
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): L.K. Olifirov, S.D. Kaloshkin, Di Zhang
      The paper presents a method of manufacturing highly filled aluminum-carbon nanotubes/epoxy composites. Aluminum and aluminum-carbon nanotubes powder with various particle-size distributions and morphologies were obtained by high-energy ball milling. Thermal conductivity and compressive stress-strain behavior of aluminum/epoxy composites strongly depended on the mean size of aluminum particles and carbon nanotubes content. The thermal conductivity of 23W/m·K and compressive strength of 160MPa were achieved for the aluminum/epoxy composite with 80wt% (or 63vol.%) filler loading. Additions of 2wt% of carbon nanotubes led to an increase in the compressive strength of the aluminum/epoxy composite from 160 to 195MPa, but they impaired the value of thermal conductivity (13.5W/m·K).

      PubDate: 2017-07-12T13:13:18Z
  • Influence of chain transfer agent on structure/property relation of
           polymer nanocomposites with functionalized carbon nanotubes
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Miftah U. Khan, Vincent G. Gomes
      Nanocomposites comprising polystyrene/carbon nanotube (PS/CNT) were synthesized via in-situ emulsion polymerization, where the CNTs were functionalized by an unsaturated organic fatty acid. The effect of chain transfer agent (CTA) on nanocomposite synthesis and structure-property relationships were investigated. The presence of CTA affected the polymer molar mass and subsequently the structure of the nanocomposites was altered as a result of the chain length variation. The TEM images showed structural modification of the nanocomposite matrix, and in particular the effect on CNT orientation on using CTA. The composites without CTA (PS/CNT) and with CTA (PS/CNT@CTA) showed significant influence of CTA not only in terms of polymerization kinetics and monomer conversion, but also on the final thermomechanical properties. The mechanical and thermal properties of the PS/CNT nanocomposites were found to be substantially altered when CTA was used during the polymerization process, which were explained in the light of composite structural changes on using CTA.

      PubDate: 2017-07-12T13:13:18Z
  • Acoustic energy absorption properties of fibrous materials: A review
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Xiaoning Tang, Xiong Yan
      Fibrous materials have been widely used in noise reduction due to the porous structures. In this review, available studies regarding the prediction methods of acoustic absorption coefficient are gathered. Empirical model could predict the acoustic absorption coefficient based on facile airflow resistivity, while microstructural model is determined by detailed structural parameters of fibrous materials. Various fibrous materials including inorganic and metallic fibers, synthetic fibers, natural fibers, and nanofibrous membranes for noise reduction are reviewed. Inorganic and metallic fibers have the advantages of corrosion resistance, high temperature resistance and long service life. The tailored cross-sections of synthetic fibers such as circle, hollow and triangle are beneficial to improve acoustic absorption properties. Natural fibrous materials are biodegradable, renewable and eco-friendly. Nanofibrous materials are lightweight and have good potential in low frequency noise reduction. Herein, we summarized the recent advances concerning the acoustic absorption of various fibrous materials.

      PubDate: 2017-07-12T13:13:18Z
  • Prediction of delamination onset and growth for AP-PLY composite laminates
           using the finite element method
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Weiling Zheng, Christos Kassapoglou
      A recently developed fibre placement architecture, Advanced Placed Ply (AP-PLY), has been shown to have promising damage tolerance characteristics for composite structures. Understanding delamination creation and growth in such architecture is of particular concern. Approaches to predict delamination onset in AP-PLY architectures and to analyse delamination growth are presented. The recovered interlaminar stresses between layers combined with a maximum stress criterion were used to determine delamination onset of simple AP-PLY composite laminates under out-of-plane loads. 2D finite element models with cohesive elements inserted at the interfaces of woven layers were used to evaluate the delamination initiation and propagation in different woven patterns of simple AP-PLY composite beams. The predictions were compared to results from the stress recovery method and to test results. The parameters of the woven pattern, such as woven angle, number of woven plies, number of straight filling plies, and the location of the woven patterns through the thickness direction, were investigated and shown to have a significant effect on delamination creation and growth.

      PubDate: 2017-07-12T13:13:18Z
  • Residual mechanical properties of carbon fibre reinforced thermoplastics
           with thin-ply prepreg after simulated lightning strike
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Shinichiro Yamashita, Yoshiyasu Hirano, Takeo Sonehara, Jun Takahashi, Kazumasa Kawabe, Tetsuhiko Murakami
      This study experimentally examined the residual mechanical properties of a carbon-fibre/polyamide-6 laminate and randomly-oriented carbon-fibre strand (ROS) thermoplastic composites with thin-ply prepreg after a simulated lightning strike, and compared the results with those of a carbon-fibre/epoxy laminate fabricated from thick-ply prepreg. The damage was characterized by visual inspection, ultrasonic scanning, and optical microscopy. The residual mechanical properties were evaluated using a four-point flexural test. The flexural strength of the carbon-fibre/epoxy laminate was considerably reduced due to delamination, whereas the carbon-fibre/polyamide-6 laminate with a thin-ply prepreg exhibited improved retention of flexural properties. Lightning damage to ROS composites was spread over larger areas and depths, while being scattered and spotted, consistent with superior retention of flexural strength. Moreover, the flexural properties of intact and damaged ROS composites were improved by thin-ply prepreg. These results suggest that the application of thin-ply prepreg to thermoplastics affords composites with superior mechanical properties and lightning resistance.

      PubDate: 2017-07-02T14:03:44Z
  • One-pot preparation of porous piezoresistive sensor with high strain
           sensitivity via emulsion-templated polymerization
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Lei Yang, Ruiying Wang, Qingting Song, Yu Liu, Qiangqiang Zhao, Yifeng Shen
      Flexible conductive polymer composite foams (CPCFs) are considered as promising materials for piezoresistive sensors. However, most of them have low strain sensitivity with gauge factor (GF) of around 1.0. Herein, for the first time, W/O emulsion-templated polymerization is developed to fabricate graphene-based flexible CPCFs with high strain sensitivity. Compared to the literature-reported CPCFs, our materials have conductive network with higher specific surface area, improving conductive pathways formation between fillers under compression. In the vicinity of conductive percolation threshold, the CPCF has highest GF of 6.0 within 0–5% strain range and piezoresistive stability, demonstrating its high strain sensitivity and promising applicability in strain sensors.
      Graphical abstract image

      PubDate: 2017-07-02T14:03:44Z
  • Experimental and numerical investigations on formability of
           out-of-autoclave thermoset prepreg using a double diaphragm process
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Hassan Alshahrani, Mehdi Hojjati
      The formability of textile out-of-autoclave thermoset prepreg using double diaphragm forming has been investigated to produce a component for aerospace applications. A one-step procedure has been used for both the forming and curing processes using the same experimental setup. A finite element model has been developed to simulate the double diaphragm forming process, with consideration for the diaphragm material properties at forming conditions. To identify potential causes for wrinkle development, important considerations, such as local fiber compressive stresses, shear angle distributions, and stacking lay-up sequences, have been analyzed. Furthermore, different forming simulation scenarios were applied to reduce the wrinkle defects. Results indicate that a change in lay-up sequences significantly affects the formability; thus, wrinkle formations cannot be avoided at challenging locations for some lay-up arrangements. The forming simulations are in agreement with the experimental results in terms of prediction of large wrinkles and intra-ply shear. Meanwhile, high local compressive stress regions provide a good indication for where the critical areas appear, which can be considered when the small wrinkles cannot be predicted with the element size used.

      PubDate: 2017-07-02T14:03:44Z
  • Thermal conductivity and thermo-physical properties of
           nanodiamond-attached exfoliated hexagonal boron nitride/epoxy
           nanocomposites for microelectronics
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Yinhang Zhang, Jang Rak Choi, Soo-Jin Park
      This research focused on evaluating the thermal and physical properties of a composite reinforced with nanodiamonds and epitaxial boron nitride in an epoxy matrix. Nanodiamond-attached exfoliated hexagonal boron nitride nanoplates were fabricated using 4,4′-methylene diphenyl diisocyanate as the coupling agent. The morphology and structure of boron nitride (BN), exfoliated hexagonal BN nanoplates (EBN), and nanodiamond-attached EBN nanoplates (NDEBN) were determined. Epoxy composites were fabricated by in-situ polymerization and reinforced with various concentrations of either EBN or NDEBN nanoplates. These composites exhibited high thermal stability and high thermal conductivity, attributed to the exceptional thermal stability and thermal conductivity inherent in nanodiamond materials. In addition, inserting nanodiamond particles between BN layers prevented the BN nanosheet from forming agglomerates. We also found that nanodiamond particles improved dynamic mechanical properties by acting as a crack pinning role, which could restrict the molecular mobility of the epoxy.

      PubDate: 2017-07-02T14:03:44Z
  • Evaluation of the role of functionalized CNT in glass fiber/epoxy
           composite at above- and sub-zero temperatures: Emphasizing interfacial
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Rajesh Kumar Prusty, Dinesh Kumar Rathore, Bankim Chandra Ray
      Present work is aimed to elucidate the temperature dependant reinforcement efficiency due to the chemical restructuring of the nano-filler/matrix interphase in carbon nanotube embedded glass fiber/epoxy composite. Oxidized CNT/glass/epoxy composite exhibits 25% and 10% better strength than control glass/epoxy (GE) and pristine CNT/glass/epoxy composites respectively, at room temperature. Covalently bonded CNT/epoxy interface in oxidized nanotube modified epoxy matrix restricts the interfacial debonding to a better extent than pristine one upon excursion to elevated temperature. However, due to massive interfacial decohesion, both these nanophased GE composites result in inferior strength over control GE at 110°C. On the contrary, mechanical gripping at the CNT/epoxy interface at lower temperature maximizes its failure strength, resulting in an admirable structural material for low and cryogenic temperature applications. Thermo-mechanical properties and microscopic evidences of the interfaces at nanoscale (CNT/epoxy) and microscale (glass/epoxy) divulge the synergetic strengthening effect due to both chemical functionalization and low temperature environment.

      PubDate: 2017-07-02T14:03:44Z
  • Improvement of thermal conductivities for PPS dielectric nanocomposites
           via incorporating NH2-POSS functionalized nBN fillers
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Xutong Yang, Lin Tang, Yongqiang Guo, Chaobo Liang, Qiuyu Zhang, Kaichang Kou, Junwei Gu
      The proposed combining method of silane coupling agent of γ-aminopropyl triethoxy silane/aminopropyllsobutyl polyhedral oligomeric silsesquioxane (KH-560/NH2-POSS) was performed to functionalize the surface of hexagonal nanometer boron nitride fillers (f-nBN), aiming to fabricate the f-nBN/polyphenylene sulfide (f-nBN/PPS) nanocomposites with excellent thermal conductivities, outstanding thermal stabilities and optimal dielectric properties. The usage of f-nBN fillers was benifit for improving the thermally conductive coefficient (λ) and decreasing dielectric constant (ε) values of the PPS nanocomposites. The f-nBN/PPS nanocomposite with 60wt% f-BN fillers was an excellent dielectric nanocomposite with high λ & ideal ε values and outstanding thermal stability, λ of 1.122W/mK (increased by 400% compared to that of pristine PPS matrix), ε of 3.99 and THeat-resistance index (THRI ) beyond 275°C, which holds potential for electronic packaging materials and ultra high voltage electrical apparatus.

      PubDate: 2017-07-02T14:03:44Z
  • Non-destructive monitoring of delamination healing of a CFRP composite
           with a thermoplastic ionomer interlayer
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): W. Post, M. Kersemans, I. Solodov, K. Van Den Abeele, S.J. García, S. van der Zwaag
      A comparative study is performed on the monitoring of delamination healing in CFRP-ionomer sandwich composites by non-destructive techniques and destructive compression testing. Artificial delaminations of various areal dimensions and nature were introduced during production of the composites. The extent of the delamination and the healing thereof was monitored in both air and water-coupled ultrasonic C-scan experiments as well as by the frequency shift of the local defect resonance (LDR). It is shown that the LDR approach can be used to detect the early stage healing of the delaminations while ultrasonic C-scanning techniques are very effective to determine the extent of healing in the final stages of the repair process. A quasi-linear relation was observed between the delaminated area measured with ultrasonic C-scan and the compressive failure strength in destructive testing. This correlation shows the beneficial effect on the compression strength of the delaminated area reduction by on-demand healing.

      PubDate: 2017-07-02T14:03:44Z
  • Graphene for flame-retarding elastomeric composite foams having strong
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Sherif Araby, Jihui Li, Ge Shi, Zheng Ma, Jun Ma
      It is a great challenge to make elastomeric polymer foams antistatic, flame-retardant and mechanically robust. The challenge was addressed herein by in situ polymerizing polyvinyl alcohol, formaldehyde and graphene sheets. The graphene sheets – each in average being ∼5nm thick – had a carbon to oxygen atomic ratio of 9.8 and a Raman ID /IG of 0.03. The sheets proved to react with formaldehyde building up a strong interface for the composites, and the reaction promoted the exfoliation and dispersion of graphene sheets in the matrix. They were found to create a large number of fine pores to the composites. Graphene sheets at 0.12vol% increased the foam water retention rate from 346% to 784%. These composites had a percolation threshold of electrical conductivity at 0.023vol%. The composites reached a limiting oxygen index of 59.4, implying an exceptional self-extinguishing performance.

      PubDate: 2017-07-02T14:03:44Z
  • Improved durability of lignocellulose-polypropylene composites
           manufactured using twin-screw extrusion
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Elisa Koivuranta, Maiju Hietala, Ari Ämmälä, Kristiina Oksman, Mirja Illikainen
      The objective of this study was to investigate the use of peat as a potential lignocellulose source in composites manufactured by twin-screw extrusion. The effects of peat decomposition rate and particle size on the mechanical properties and moisture resistance of peat-polypropylene (PP) composites under cyclic conditions were evaluated. The properties of the peat-PP composites were compared to commercial lignocellulosic fibre products, namely wood-plastic composite (WPC), medium density fibreboard (MDF) and hardboard (HB). The results show that prior cyclic freeze-thaw testing peat-PP composites had properties equal to commercial WPC, but their mechanical permanence was better after freeze-thaw conditioning. When moderately decomposed, smaller particle–size peat was used, peat-PP composites had better dimensional stability, though particle size did not affect as much as the decomposition degree. Thus, the chemical structure of peat has a greater influence on composite durability, as better water and weather resistance are achieved with peat that is more decomposed.

      PubDate: 2017-07-02T14:03:44Z
  • Resin impregnation behavior in carbon fiber reinforced polyamide 6
           composite: Effects of yarn thickness, fabric lamination and sizing agent
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Satoshi Kobayashi, Takamasa Tsukada, Tetsuya Morimoto
      In the present study, the effects of yarn thickness, fabric lamination (such as number of fabric plies) and sizing content on resin impregnation behavior in carbon fiber reinforced polyamide 6 composites were investigated. Micro-braided yarn (MBY) was fabricated using carbon fiber yarn consisted of 3000, 6000 and 12000 carbon fibers and polyamide 6 fiber yarn. Carbon fiber yarn with different sizing content was also used for MBY. Plain woven fabrics were made with MBY. Composite plates were compression-molded using the fabrics. Impregnation ratio was measured by surface observation of the cross-section of the composite. From the results, it is confirmed that the composites with dense fabrics inhibited fiber yarn flattening and restricted the influence of fabric lamination. Resin impregnation behavior was inhibited with sizing contents.

      PubDate: 2017-07-02T14:03:44Z
  • Low velocity impact resistance and energy absorption of environmentally
           friendly expanded cork core-carbon fiber sandwich composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Joe Walsh, Hyung-Ick Kim, Jonghwan Suhr
      This study investigates the use of expanded cork (a 100% natural lightweight agglomerate material) as a core material in composite sandwich structures with carbon fiber face sheets. The characterization performed focused particularly on energy absorption capability. Rohacell® 110 IG, a synthetic foam commonly used as a core material in high performance aerospace applications, was also used and characterized to compare the energy absorbing characteristics of the sandwich composites. Bending tests were done to examine the stiffness of the sandwich beams. Wavenumber and damping tests were performed to characterize the acoustic and vibrational damping properties of the composites. Both full penetration and partial penetration low velocity impact tests were completed to determine the damage resistance of the composites. It was seen that when compared to the synthetic foam, expanded cork showed a decrease in bending stiffness, but a large improvement in acoustic, damping, and impact damage resistance characteristics. It seems that expanded cork could be an attractive lightweight sandwich core material that will allow for increased energy absorption and will also reduce the carbon footprint of the structures.

      PubDate: 2017-07-02T14:03:44Z
  • Elongated TiO2 nanotubes directly grown on graphene nanosheets as an
           efficient material for supercapacitors and absorbents
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Yimei Zhang, Fei Wang, Hao Zhu, Dandan Zhang, Jie Chen
      The successful applications of supercapacitors and adsorbents hinge on the development of highly stable and efficient materials. Herein, we report a facile approach to fabricate a novel type of three dimensional porous materials composed of elongated TiO2 nanotubes (eTNTs) and reduced garphene oxide (rGO). The eTNTs-rGO composites is the graphene oxide (GO) nanosheets joins with commercially available TiO2 nanoparticles through the hydrothermal process combined with mechanical stirring, which converts the TiO2 nanoparticles to elongated TiO2 nanotubes (eTNTs) and the alkaline medium simultaneously converts GO to rGO. The electrochemical performance of eTNTs-rGO composites is measured by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy in 1M Na2SO4 electrolyte. The specific capacitance is 338Fg−1 at a scan rate of 5mVs−1. The eTNTs-rGO composites electrode exhibited long-term cycle stability, retaining about 93.3% specific capacitance after 3000 cycles. Additionally, the eTNTs-rGO composites show excellent adsorption capacity for bisphenol A, which can reach 159.3mgg−1. The superb electrochemical performance and adsorption capacity demonstrated the potential of eTNTs-rGO composites as an attractive material for energy storage and environmental.

      PubDate: 2017-07-02T14:03:44Z
  • Joining of carbon fibre reinforced polymer (CFRP) composites and aluminium
           alloys – A review
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): A. Pramanik, A.K. Basak, Y. Dong, P.K. Sarker, M.S. Uddin, G. Littlefair, A.R. Dixit, S. Chattopadhyaya
      This paper investigates comprehensive knowledge regarding joining CFRP and aluminium alloys in available literature in terms of available methods, bonding processing and mechanism and properties. The methods employed comprise the use of adhesive, self-piercing rivet, bolt, clinching and welding to join only CFRP and aluminium alloys. The non-thermal joining methods received great attention though the welding process has high potential in joining these materials. Except adhesive bonding and welding, other joining methods require the penetration of metallic pins through joining parts and therefore, surface preparation is unimportant. No model is found to predict the properties of jointed structures, which makes it difficult to select one over another in applications. The choice of bonding methods depends primarily on the specific applications. The load-bearing mechanism of bolted joints is predominantly the friction that is the first stage resistance. Hybrid joints performance is enhanced by combining rivets, clinch or bolts with adhesives.

      PubDate: 2017-06-22T07:39:30Z
  • Conductive thermoplastic polyurethane composites with tunable
           piezoresistivity by modulating the filler dimensionality for flexible
           strain sensors
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Yanjun Zheng, Yilong Li, Kun Dai, Mengran Liu, Kangkang Zhou, Guoqiang Zheng, Chuntai Liu, Changyu Shen
      Conductive elastomer composites based strain sensors have attracted increasing attention recently. In this paper, flexible composites were prepared by incorporating thermoplastic polyurethane (TPU) with zero-dimensional carbon black (CB) and one-dimensional carbon nanotubes (CNTs), respectively. CNTs/TPU showed a lower percolation threshold (0.28wt.%) and wider sensing range (0-ca.135% strain), compared with CB/TPU (1.00wt.% and 0-ca. 90% strain). CB/TPU composites exhibited a higher sensitivity with a GF of 10.8 under 20% strain, while CNTs/TPU showed a lower GF of 6.8. In cyclic loading-unloading test, both the two composites showed non-monotonic ‘shoulder peak’ behaviors. For CB/TPU, the ‘first peak’ was higher than the ‘second peak’; interestingly, CNTs/TPU presented a negative strain effect. The discrepancy was mainly ascribed to the difference of filler dimensionality and the evolution of the conductive network.

      PubDate: 2017-06-22T07:39:30Z
  • Fatigue modeling in composites with the thick level set interface method
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): M. Latifi, F.P. van der Meer, L.J. Sluys
      This paper presents a new discontinuous damage model for modeling fatigue crack growth in composites. This new fatigue model is formulated based on the thick level set interface approach which we developed recently. In this approach the thick level set (TLS) method is combined with interface elements for modeling delamination growth. Crack growth under cyclic loading is described with the Paris relation. In contrast with popular cohesive zone methods, this new approach provides an accurate non-local evaluation of the energy release rate as well as a framework in which the crack growth rate can be directly imposed. The proposed 3D mixed-mode model is validated against experimental and theoretical data.

      PubDate: 2017-06-22T07:39:30Z
  • Influence of specimen pre-shear and wrinkling on the accuracy of uniaxial
           bias extension test results
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): J. Alsayednoor, F. Lennard, W.R. Yu, P. Harrison
      The influence of unintended specimen pre-shear and out-of-plane wrinkling on the accuracy of shear angle and axial force results, measured during a uniaxial bias extension (UBE) test on engineering fabrics, is examined. Three techniques of measuring test kinematics are investigated, including manual image analysis, 2-D and 3-D full-field analysis. Error introduced by specimen pre-shear is shown to influence test results in different ways, depending on analysis technique. Procedures to take specimen pre-shear error into account when interpreting results are demonstrated, though an important recommendation resulting from this investigation is to minimise pre-shear as much as possible. Out-of-plane wrinkling is shown to create significant errors in kinematic data when using 2-D analysis methods (up to 20% overestimates of measured shear angle). It is shown that wrinkle-error can be corrected if 3-D stereoscopic analysis methods are employed.

      PubDate: 2017-06-22T07:39:30Z
  • Modification of GO based on click reaction and its composite fibers with
           poly(vinyl alcohol)
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Juan Li, Yao Cheng, Shiyu Zhang, Yajun Li, Jun Sun, Chuanxiang Qin, Jianjun Wang, Lixing Dai
      We present a novel approach to the functionalization of graphene oxide (GO) based on click reaction, in which GO was modified by 3-mercaptopropionic acid (MPA) via thiol-ene reaction in mild reacting conditions. The modified GO (mGO) was bonded with poly(vinyl alcohol) (PVA) to get PVA grafted mGO (p-mGO) and the composite fibers of PVA and p-mGO were prepared using a wet-spinning process. Compared with PVA grafted GO (p-GO) without the process of click reaction, where PVA chains only distribute at the edge of GO, much more PVA chains are bonded on the surface of mGO. Therefore, p-mGO has better dispersibility in PVA than p-GO because of better interaction between p-mGO and PVA, resulting in much higher mechanical properties of PVA/p-mGO than PVA/p-GO. For example, the strength of PVA/p-mGO fiber is up to 908.93MPa, 57% higher than that of PVA/p-GO fiber at the same GO loading of 0.4wt%.
      Graphical abstract image

      PubDate: 2017-06-22T07:39:30Z
  • Ternary hybrid nanoparticles of reduced graphene oxide/graphene-like
           MoS2/zirconia as lubricant additives for bismaleimide composites with
           improved mechanical and tribological properties
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Zhengyan Chen, Hongxia Yan, Qing Lyu, Song Niu, Cheng Tang
      To develop low friction coefficient and high wear resistance composites, the ternary hybrid nanoparticles consisting of reduced graphene oxide (rGO), graphene-like MoS2 and ZrO2 with active amino groups (NH2-rGO/MoS2/ZrO2) were successfully prepared through a facile and effective one-pot hydrothermal method. Subsequently, the bismaleimide (BMI) composites with different weight fraction of fillers were fabricated to enhance the mechanical and tribological properties of BMI resin. The results demonstrate that the layers of MoS2 in the filler can significantly decrease and just a little content of fillers can remarkably improve the mechanical and tribological properties of BMI resin. In particular, the average friction coefficient and volume wear rate of the BMI composite containing 0.4wt.% NH2-rGO/MoS2/ZrO2 can reach the lowest value of 0.15 and 1.5×10−6 mm3/(N·m), respectively. The excellent friction-reducing and wear-resistance performances are mainly attributed to the good synergistic effect among the rGO nanosheets, graphene-like MoS2 and ZrO2.
      Graphical abstract image

      PubDate: 2017-06-22T07:39:30Z
  • RGO/TPU composite with a segregated structure as thermal interface
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): An Li, Cong Zhang, Yang-Fei Zhang
      Thermal management has become a serious problem with the development of electronics, where thermal interface material (TIM) is crucial for heat transfer from the device to heat sink. In this work, reduced graphene oxide/thermoplastic polyurethane (RGO/TPU) composites with a segregated structure were proposed and prepared by a simple method to obtain superior thermal conductive property and used as TIM. The microstructures and thermal properties of RGO/TPU composites were characterized, as well as heat transfer performance and thermal fatigue resistance. The obtained composite, at an ultralow graphene loading of 1.04wt.%, exhibits a high thermal conductivity (0.8Wm−1 K−1). Furthermore, the composite as a TIM presents a good performance in practical application and has a stable performance in the thermal cycling test.

      PubDate: 2017-06-22T07:39:30Z
  • Modification of basalt fibre using pyrolytic carbon coating for sensing
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Bin Hao, Theresa Förster, Edith Mäder, Peng-Cheng Ma
      This paper reported the modification of basalt fibre (BF) using a chemical vapour deposition (CVD) method, aiming at enhancing the functionality of BF for sensing applications. Various techniques were used to characterize the surface, electrical and mechanical properties of fibres before and after CVD treatment. The results showed that a thin layer of pyrolytic carbon with a thickness of 15–30nm was deposited on the fibre surface, making the insulating fibres electrically conductive. Upon embedding a strand of these fibres into epoxy resin, the corresponding composites exhibited a piezoresistive effect with the highest gauge factor of 38.6 under the mechanical load. Analysis of the stress–strain curve along with the corresponding electrical resistance of the sample confirmed that BF with pyrolytic carbon coating could be used as both reinforcement and a sensor to monitor structural damage in composite structures.

      PubDate: 2017-06-22T07:39:30Z
  • PvT-HADDOC: A multi-axial strain analyzer and cure monitoring device for
           thermoset composites characterization during manufacturing
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Mael Péron, Romain Cardinaud, Nicolas Lefèvre, Julien Aubril, Vincent Sobotka, Nicolas Boyard, Steven Le Corre
      Process-induced strains have an important role on the development of residual stresses and final dimensions of composite parts. It is of utmost importance to characterize them in order to optimize the process conditions. This paper is devoted to the presentation of a new device, which can measure the curing strains of thermosetting composite materials under process representative conditions (temperature and pressure up to 200°C and 1.0MPa, respectively). The sample strains are recorded along two directions (through-thickness and in-plane), and the degree of cure is estimated in the same time. The device has been thoroughly validated thanks to several tests, demonstrating its accuracy. Two specific materials were tested, i.e. a glass-vinylester SMC and a UD carbon-epoxy composite. The measured coefficients of thermal expansion and of chemical shrinkage are in excellent agreement with both theoretical and experimental values available in the literature.

      PubDate: 2017-06-22T07:39:30Z
  • Enhancing mechanisms of multi-layer graphenes to cementitious composites
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Baoguo Han, Qiaofeng Zheng, Shengwei Sun, Sufen Dong, Liqing Zhang, Xun Yu, Jinping Ou
      The mechanical property and underlying enhancing mechanisms of cementitious composites filled with multi-layer graphenes (MLGs) are investigated in this paper. Research results indicate that the addition of MLGs can achieve an enhancement of 54% in compressive strength and a reinforcement of 21% in flexural strength to cementitious composites, respectively. The strengthening effects can be attributed to extensive distribution network of MLGs inside matrix, decreasing ratio of water to cement and self-curing caused by water adsorption and release of MLGs, reducing primary cracks due to MLGs presence, strong bonding between MLGs and matrix, and lowering orientation index of calcium hydroxide crystal in hydration products of cementitious composites. It is therefore concluded that MLGs are effective nanoscale fillers for reinforcing cementitious composites.

      PubDate: 2017-06-22T07:39:30Z
  • Interlaminar toughening of woven fabric carbon/epoxy composite laminates
           using hybrid aramid/phenoxy interleaves
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Doris W.Y. Wong, Han Zhang, Emiliano Bilotti, Ton Peijs
      The influence of a hybrid interleaf system based on aramid and phenoxy fibres on the interlaminar toughness and damage tolerance of epoxy based carbon fibre reinforced plastic (CFRP) laminates was studied. An interleaf consisting of a non-woven aramid mat was either used on its own or in combination with epoxy-dissolvable thermoplastic phenoxy fibres. These thermoplastic phenoxy fibres are miscible with the epoxy resin and phase separate upon curing to improve ductility and toughness. Tensile properties, Mode-I fracture toughness, interlaminar shear strength (ILSS), as well as compression after impact (CAI) properties of the toughened CFRP laminates have all been characterized and analysed. Fractography was used to identify the toughening mechanisms in the CFRP laminates with different interleaf compositions. At the optimal interleaf composition, obvious synergic effects were found in terms of the overall mechanical performance of these hybrid composite laminates, including a near 150% increment in interlaminar fracture toughness in comparison to a reference CFRP laminate.

      PubDate: 2017-06-22T07:39:30Z
  • Shape memory behaviors in cylindrical shell PLA/TPU-cellulose nanofiber
           bio-nanocomposites: Analytical and experimental assessment
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): Mohsen Barmouz, Amir Hossein Behravesh
      Experimental and analytical investigations were conducted to assess shape memory behavior of Polylactic acid-thermoplastic polyurethane/cellulose-nanofiber bio-nanocomposites. Shape memory polymers were manufactured for experimental evaluation in cylindrical shell form. Subsequently, analytical assessment of shape memory behavior of thin sheet samples was accomplished based on the isothermal thermomechanical tests. Besides, evaluation of the acquired inclusive responses was performed for the cylindrical shell shape memory polymers, utilizing variance analysis. The results were indicative of dominant effect of programming temperature on force recovery ratio. Additionally, it showed that a higher force recovery can be attained at the higher weight ratios of cellulose-nonofiber and thermoplastic polyurethane. The analytical examination of the compounds with and without cellulose nanofibers correlates with the experimental results so that adding cellulose nanofibers to the polymeric matrix imposed notable promotion of stress recovery (over 40%) with a slight reduction in strain recovery.

      PubDate: 2017-06-22T07:39:30Z
  • Permeability of carbon fibre PEEK composites for cryogenic storage tanks
           of future space launchers
    • Abstract: Publication date: October 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 101
      Author(s): M. Flanagan, D.M. Grogan, J. Goggins, S. Appel, K. Doyle, S.B. Leen, C.M. Ó Brádaigh
      This work presents an experimental investigation into the permeability of carbon fibre (CF) polyetheretherketone (PEEK) for cryogenic storage tanks for space applications. The effects of cryogenic cycling, manufacturing method, PEEK matrix type, fibre type, cryogenic temperatures, pressure, and thickness on the permeability of CF-PEEK laminates are investigated. Laminates are manufactured using autoclave, press and in-situ laser assisted automated tape placement (ATP) consolidation. Optical microscopy is used to characterise the microstructure of test samples. The results show that, for undamaged autoclaved CF-PEEK samples, the permeability remains essentially constant for the ranges of pressures and thicknesses tested. Samples manufactured using the ATP process and samples which were damaged by cryogenic cycling, had a higher leak rate than autoclaved and pressed samples. For cryogenically cycled samples, the leak rate was shown to be dependent on the damage state of the microstructure.

      PubDate: 2017-06-22T07:39:30Z
  • Effects of graphene oxide aggregates on hydration degree, sorptivity, and
           tensile splitting strength of cement paste
    • Abstract: Publication date: September 2017
      Source:Composites Part A: Applied Science and Manufacturing, Volume 100
      Author(s): Xiangyu Li, Zeyu Lu, Samuel Chuah, Wengui Li, Yanming Liu, Wen Hui Duan, Zongjin Li
      It has recently been found the graphene oxide (GO) aggregates form in cement paste due to the chemical cross-linking of calcium cations. Therefore, the effects of GO addition on the properties of cement based materials should be dependent on the properties of GO aggregates rather than GO nanosheets. In this study, GO aggregates were first characterized by particle size measurement. Then, the effects of GO aggregates on the degree of hydration, sorptivity, and tensile strength of cement paste were investigated. The aspect ratio of GO aggregates is much larger than that of the original GO nanosheets. Compared to plain cement paste, the increase of non-evaporable water content of the cement paste was found to be very limited, around 1.17% and 3.90% for cement pastes containing 0.02% and 0.04% by weight GO, respectively. The sorptivity of cement paste, especially the secondary sorptivity, was notably reduced for GO incorporated cement paste. The tensile strength was significantly improved by GO aggregates. Incorporation of 0.04% by weight GO increased the tensile strength by 67% compared to that of plain cement paste.

      PubDate: 2017-05-13T04:02:22Z
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