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  Subjects -> ENGINEERING (Total: 2298 journals)
    - CHEMICAL ENGINEERING (192 journals)
    - CIVIL ENGINEERING (192 journals)
    - ELECTRICAL ENGINEERING (104 journals)
    - ENGINEERING (1209 journals)
    - ENGINEERING MECHANICS AND MATERIALS (385 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (69 journals)
    - MECHANICAL ENGINEERING (92 journals)

ENGINEERING (1209 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 252)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
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: 26)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 30)
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: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 2)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 5)
AIChE Journal     Hybrid Journal   (Followers: 32)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 17)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 8)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 18)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 1)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
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: 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: 4)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 30)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 7)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 268)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 193)
Composites Part B : Engineering     Hybrid Journal   (Followers: 274)
Composites Science and Technology     Hybrid Journal   (Followers: 192)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computers & Geosciences     Hybrid Journal   (Followers: 29)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 6)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 32)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 7)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 43)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
Corrosion Series     Full-text available via subscription   (Followers: 6)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | Last

Journal Cover Composites Part A : Applied Science and Manufacturing
  [SJR: 1.599]   [H-I: 113]   [193 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1359-835X
   Published by Elsevier Homepage  [3118 journals]
  • Bioinspired mechanical and thermal conductivity reinforcement of highly
           explosive-filled polymer composites
    • Abstract: Publication date: April 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 107
      Author(s): Guansong He, Jiahui Liu, Feiyan Gong, Congmei Lin, Zhijian Yang
      The low mechanical and thermal conductivity property of polymer bonded explosives (PBX) could greatly restrict its further practical application. In this study, inspired by mussels, a facile and noncovalent modification for three carbon nanofillers including multiwalled carbon nanotubes (CNTs), graphene and graphene nanoplates (GNPs), was adopted by the self-polymerization of dopamine. Next, in-depth characterizations, including SEM, TEM, FTIR, FT-Raman and TGA, confirmed that the carbon nanofillers were successfully coated by a dense graphite-like structure polydopamine (PDA) without destroying the original structures, through the oxidation of dopamine at room temperature. The polydopamine-coated nanofillers (pFillers) were further incorporated into PBX matrix. Compared to neat PBX and PBX/carbon nanocomposites, the PBX/pFillers nanocomposites exhibited improved tensile and compression strength, creep resistance, and thermal conductivity. The work presented herein greatly broadens the application scope of the bioinspired dopamine, and will be potential of interest to the communities in highly particle-filled polymer composites.

      PubDate: 2017-12-27T03:25:03Z
       
  • A multi-pattern compensation method to ensure even temperature in
           composite materials during microwave curing process
    • Abstract: Publication date: April 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 107
      Author(s): Jing Zhou, Yingguang Li, Nanya Li, Shuting Liu, Libing Cheng, Shaochun Sui, James Gao
      Microwave curing technologies have many advantages in manufacturing fiber reinforced polymer composite materials used in aerospace products, compared with traditional autoclave curing technologies. However, the uneven electromagnetic field of microwave in the cavity of the curing chamber results in uneven temperature on the surface of composite laminates during curing, which has been a major obstacle in industrial applications worldwide. Existing methods attempted to solve the problem by the random superposition of uneven electromagnetic fields, but the results were still not satisfactory to meet the high quality requirements of aerospace parts. This paper reveals the one-to-one correspondence between heating patterns of composite parts and microwave curing system settings, and reports a new concept to solve this problem by continuously monitoring and compensating the uneven temperature distribution in real-time. Experimental results from both fiber optical fluorescencesensors and infrared thermal imagers showed significant improvement in temperature uniformity compared with existing methods.

      PubDate: 2017-12-27T03:25:03Z
       
  • Dynamic bridging mechanisms of through-thickness reinforced composite
           laminates in mixed mode delamination
    • Abstract: Publication date: March 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 106
      Author(s): Hao Cui, Mehdi Yasaee, Stephen R. Hallett, Ivana K. Partridge, Giuliano Allegri, Nik Petrinic
      Delamination resistance of composite laminates can be improved with through-thickness reinforcement such as Z-pinning. This paper characterises the bridging response of individual carbon fibre/BMI Z-pins in mixed mode delamination at high loading rate using a split Hopkinson bar system. The unstable failure process in quasi-static tests, was also captured with high sampling rate instruments to obtain the complete bridging response. The energy dissipation of the Z-pins were analysed, and it was found that the efficacy of Z-pinning in resisting delamination growth decreased with an increase in mixed mode ratio, with a transition from pull-out to pin rupture occurring. The Z-pin efficacy decreased with loading rate for all mode mix ratios, due to the changing in failure surface with loading rate and rate-dependent frictional sliding.

      PubDate: 2017-12-27T03:25:03Z
       
  • Thermal conductivity and mechanical properties of flake graphite/copper
           composite with a boron carbide-boron nano-layer on graphite surface
    • Abstract: Publication date: March 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 106
      Author(s): H Bai, C Xue, JL Lyu, J Li, GX Chen, JH Yu, CT Lin, DJ Lv, LM Xiong
      Graphite/copper composites had attracted significant recent attention for thermal management applications due to their superior thermal properties, low cost and ease of machining. However, achieving the enhancement of mechanical properties of composites with high thermal conductivity remained challenging. In this study, graphite/copper composites had been produced by vacuum hot pressing process, in which the boron carbide-boron coating was synthesized on graphite to improve the mechanical properties of copper matrix composites with high volume fraction of graphite. The resulting composites had superior thermal conductivity (676 W/mK, 180% of copper) and apposite coefficient of thermal expansion (7.1 ppm/K), which was attributed to the homogeneous dispersion and well-controlled alignment of graphite in the composite. And the results showed that the coating on graphite slightly decreased the thermal conductivity and coefficient of thermal expansion of the composites, but evidently improved the bending strength. The flexural strength raised to 74 MPa, 42% increased with that of uncoated composite.

      PubDate: 2017-12-27T03:25:03Z
       
  • Cavitation in epoxies under composite-like stress states
    • Abstract: Publication date: March 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 106
      Author(s): Anupam Neogi, Nilanjan Mitra, Ramesh Talreja
      In a previous study (Asp et al., 1995) the experimentally observed low strains to transverse tensile failure of unidirectional (UD) polymer matrix composites were explained as an effect of triaxial (composite- like) stress state in the epoxy matrix. Assuming cavitation as an underlying mechanism for brittle cracking under triaxial stress states, a dilatation energy density based criterion was put forth (Asp et al., 1996) and was shown to predict well the transverse failure of epoxy based UD composites (Asp et al., 1996). The assumption of cavitation in the epoxy matrix has hitherto not been supported by a mechanism study. The current study attempts to provide a systematic clarification of the cavitation mechanism by molecular dynamic simulation. By imposing uniaxial, equi-biaxial and equi-triaxial tension on a simulation cell of a crosslinked epoxy, the degrees of cavitation at various stages of the stress- strain response are revealed. The results show that triaxiality of the stress states is a governing factor in cavitation of epoxies.

      PubDate: 2017-12-27T03:25:03Z
       
  • Development of biocomposites from denim waste and thermoset bio-resins for
           structural applications
    • Abstract: Publication date: March 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 106
      Author(s): Robin Temmink, Behnaz Baghaei, Mikael Skrifvars
      This paper examines the use of post-consumer denim fabric in combination with thermoset bio-resins in composite manufacturing for structural applications. Bio-epoxy and acrylated epoxidized soybean oil resin (AESO) were used as bio-resins with four different manufacturing techniques in order to create a wide scope of possibilities for research. The four techniques are: compression moulding (COM), vacuum infusion (VAC), resin transfer moulding (RTM) and hand lay-up (HND). The bio-resins were compared to a conventional polyester resin, as this is highly used for structural applications. To determine suitability for structural applications, the biocomposites were tested for their mechanical and thermal properties. Fabricated composites were characterised regarding porosity, water absorption and analysed through microscopic images of the composite. Results show both bio-epoxy and AESO are suitable for use in structural applications over a range of manufacturing techniques. Furthermore, biocomposites from bio-epoxy are superior to those from AESO resin. The conventional polyester has shown to be unsuitable for structural applications.

      PubDate: 2017-12-27T03:25:03Z
       
  • Interaction of textile variability and flow channel distribution systems
           on flow front progression in the RTM process
    • Abstract: Publication date: March 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 106
      Author(s): C. Kracke, A. Nonn, C. Koch, M. Nebe, E. Schmidt, S. Bickerton, T. Gries, P. Mitschang
      The high volume production of carbon fibre reinforced plastics needs cost efficient and robust processes. This paper investigates the influence of local textile variation on flow front progression in resin transfer moulding (RTM). To quantify the textile variation, the textile has been tested with laser triangulation, to achieve the thickness profile map of the flat textile preform. This preform is placed in a transparent flow visualisation tool and an oil is injected into the mould via two different flow channel distribution systems. The flow front progression of the fluid is continuously measured from both sides with two cameras. Furthermore, to demonstrate the influence of defects like folds from the draping process on the local filling behaviour, the textile is prepared with an artificial fold, made of additional non-crimp fabric (NCF) strips. The results show how different defects in the textile influence the local filling behaviour and how the additional flow channel distribution system can decrease the effect of these defects.

      PubDate: 2017-12-27T03:25:03Z
       
  • Impact resistance of shear thickening fluid/Kevlar composite treated with
           shear-stiffening gel
    • Abstract: Publication date: March 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 106
      Author(s): Qianyun He, Saisai Cao, Yunpeng Wang, Shouhu Xuan, Pengfei Wang, Xinglong Gong
      In this work, shear-stiffening gel (STG) was introduced into shear thickening fluid (STF)-impregnated-Kevlar® woven fabric (Kevlar/STF) to improve the impact resistance. The STF filled within the yarns of Kevlar and the STG covered the Kevlar/STF to form Kevlar/STF/STG composite. The STG in the Kevlar/STF/STG not only protected STF but also improved the impact resistance of the fabric because of its excellent shear-stiffening characteristics. A series of experiments including the yarn pull-out test, the split Hopkinson pressure bar impact test, rod penetration test, and knife cutting test were carried out to verify the enhancement effect. The improvement mechanism of the impact resistance for the Kevlar/STF/STG was studied. Under the similar anti-impact performance, the Kevlar/STF/STG possessed lower weight than the Kevlar and its strong impact resistance originated from the synergetic effect among the STF, STG and Kevlar. Therefore, the Kevlar/STF/STG exhibited broad potential in the soft body armor.

      PubDate: 2017-12-27T03:25:03Z
       
  • A model for the time-dependent compaction response of woven fiber textiles
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Mario Danzi, Christoph Schneeberger, Paolo Ermanni
      The description of the fiber bed compaction behavior is essential for the simulation of many composite manufacturing processes. In this study, we propose a material model describing the time-dependent compaction behavior of a dry fiber bed, valid for different fiber volume fractions and strain-rates. The approach is based on a linear generalized Maxwell model, in which stiffness parameters depend on strains, and relaxation times depend on strain-rates. The model parameters and functions are derived following an empirical approach, performing a curve fitting on multiple steps compaction experiments. The material considered is a carbon fiber woven fabric. The model response shows good agreement with the experimental results, proving the validity of the approach. The proposed material model uses only one set of equations to represent both the compaction and relaxation phases and can be easily implemented in numerical simulation tools.

      PubDate: 2017-12-27T03:25:03Z
       
  • Carbon foam based on epoxy/novolac precursor as porous micro-filler of
           epoxy composites
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Urszula Szeluga, Sławomira Pusz, Bogumiła Kumanek, Jerzy Myalski, Bartosz Hekner, Boyko Tsyntsarski, Rafał Oliwa, Barbara Trzebicka
      The concept of application of crumbled carbon foam obtained from polymer precursor as a filler in polymer/carbon composite was described. The carbon foam used as powdered reinforcement of composites was prepared from epoxy resin cross-linked with phenol–formaldehyde resin (novolac) in a self-foaming process followed by carbonization at not very high temperature and ambient pressure. The structure of the carbon foam filler and resultant composites was studied by microscopic and spectroscopic methods. In the final composites, there were observed good quality dispersion of micronized grains of carbon foam, with the sizes that preserve their specific porous structure, in epoxy matrix and excellent adhesion at interfacial areas. The influence of the CF filler on the properties of resultant composites were investigated. Due to valuable properties of carbon foam, resultant composites occurred to have interesting characteristics: densities similar to those of pure polymer matrix, advantageous thermal and viscoelastic properties and enhanced tribological features.

      PubDate: 2017-12-13T08:00:47Z
       
  • Hierarchical pseudo-ductile hybrid composites combining continuous and
           highly aligned discontinuous fibres
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): HaNa Yu, Marco L. Longana, Meisam Jalalvand, Michael R. Wisnom, Kevin D. Potter
      Hybrid composites allow avoiding catastrophic failure, a key limitation of composite materials, and can provide a balanced suite of modulus, strength and ductility. The aim of this research is to manufacture hierarchical hybrid composites using a combination of continuous high elongation fibres and intermingled hybrids made out of highly aligned discontinuous fibres with lower elongation to achieve pseudo-ductility through control of failure development. The HiPerDiF (High Performance Discontinuous Fibres) method that allows a high level of fibre alignment, leading to excellent mechanical properties close to continuous fibre composites, was used to produce the intermingled hybrid discontinuous fibre preforms. The hierarchical hybrid composite configuration is composed of an intermingled hybrid discontinuous fibre layer sandwiched between continuous S-glass layers. The overall stress-strain response of the intermingled hybrid composites and the hierarchical hybrid composites was investigated for different fibre types and ratios. The analytical modelling approach previously developed by the authors for interlaminated hybrid composites was modified for this new type of hierarchical composite. The experimental results were analysed and the analytical model was used to evaluate the optimised balance of constituents to maximise pseudo-ductile strain in tension.

      PubDate: 2017-12-13T08:00:47Z
       
  • Influence of temperature on the strength of resistance welded glass fibre
           reinforced PPS joints
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): N. Koutras, I. Fernandez Villegas, R. Benedictus
      In this work, the effect of temperature exposure on the strength of resistance welded joints is analysed. Glass fibre reinforced polyphenylene sulphide (GF/PPS) adherends were joined using the resistance welding technique, using a stainless steel mesh as the heating element. Single lap shear tests were performed at temperatures ranging between −50 °C and 150 °C to evaluate the strength of the welded joints. The results showed that the lap shear strength decreased with increasing temperature, except for the region between 50 °C and 90 °C where it remained constant. Fractography analysis revealed that the main failure mechanism was glass fibre/matrix debonding and the connection between the mesh and the matrix was not the weakest link at the interface of the joint at any temperatures under study. The fibre/matrix interfacial strength and the stress distribution at the joint overlap were identified as the main factors influencing the behaviour of lap shear strength with temperature.

      PubDate: 2017-12-13T08:00:47Z
       
  • Segregated conductive polymer composite with synergistically electrical
           and mechanical properties
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Wei Zhai, Shuaiguo Zhao, Yan Wang, Guoqiang Zheng, Kun Dai, Chuntai Liu, Changyu Shen
      The potential of segregated conductive polymer composites is greatly hampered due to its poor mechanical strength and brittle nature. In this work, plunger type injection molding (PTIM) is developed to achieve synergistically electrical and mechanical properties on carbon nanotubes (CNTs)/polypropylene (PP)/ultra-high molecular weight polyethylene (UHMWPE) segregated conductive polymer composite. Morphology observation indicates that the segregated CNTs conductive network was formed along the interfaces between PP and UHMWPE grains. An ultralow percolation threshold of 0.13 vol% is achieved, which is much lower than that of conventional injection molding. The strength of PTIM sample is improved; importantly, more than 10 times of improvement in elongation at break has been achieved compared to the sample obtained from frequently-used compression molding. Stability of the segregated conductive network was evaluated through dynamic strain-sensing behaviors. This paper presents a meaningful strategy towards the improvement of comprehensive performance of segregated conductive polymer composite.

      PubDate: 2017-12-13T08:00:47Z
       
  • A new approach to enhancing interlaminar strength and galvanic corrosion
           resistance of CFRP/Mg laminates
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Yingcai Pan, Xuan Wu, Zheng Huang, Guoqing Wu, Siqiang Sun, Hengjian Ye, Zongke Zhang
      In the present research, AZ31 magnesium alloy was treated by electrochemical methods in Na2SiO3-KOH-KF and KOH-KF electrolytes, and the morphological features of films formed on magnesium alloy were assessed. Besides, the effect of Mg surface features on interlaminar failure load, failure mode and galvanic corrosion resistance of CFRP/Mg laminates were investigated. The results show that removal of silicate in the Na2SiO3-KOH-KF electrolyte can cause the transition of conversion film from ceramic-like oxide film to pitted oxide film. The pitted oxide film can effectively enhance the peel strength of CFRP/Mg laminates compared with the ceramic-like oxide film, and an average enhancement of 6.5 times was observed. The pitted oxide film on magnesium can provide an excellent protection against the galvanic corrosion in CFRP/Mg laminates as the ceramic-like oxide film.

      PubDate: 2017-12-13T08:00:47Z
       
  • Microstructure and synergistic-strengthening efficiency of CNTs-SiCp
           dual-nano reinforcements in aluminum matrix composites
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Xin Zhang, Shufeng Li, Deng Pan, Bo Pan, Katsuyoshi Kondoh
      In this study, reinforcements of carbon nanotubes (CNTs) and silicon carbide particle (SiCp) in CNTs-SiCp reinforced aluminum matrix nanocomposites (AMNCs) are studied. The tensile strength of 0.5CNTs-0.5SiCp/Al increase by 94% compared with pure Al reaching 247 MPa, it also has a lifting of 14% and 56% compared with 1.0CNTs/Al and 1.0SiCp/Al. CNT-SiCp reinforcements have the synergistic enhancement effect of 1 + 1 > 2 in tensile strength. It is found that SiCp as a dispersed particle around CNTs can inhibit and delay the pulling out and peeling of CNTs to further enhance the strengthening effect of CNTs by pinning effect. Between CNTs and Al matrix, there is a nano-scale reaction transition layer which improves the mechanical properties of AMNCs by strengthening the interfacial bonding. The existences of SiCp inhibit the excessive reaction of the interface, when the tensile strength of AMNCs increases compared with pure Al, the elongation and conductivity have similar maintaining.

      PubDate: 2017-12-13T08:00:47Z
       
  • Rheological percolation behaviour and fracture properties of
           nanocomposites of MWCNTs and a highly crosslinked aerospace-grade epoxy
           resin system
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Yan Liu, Arthur Wilkinson
      The effects of incorporating MWCNT in a high-functionality epoxy resin system are reported. Oscillatory-shear rheology showed as-received MWCNT (AR-MWCNT) to have a low degree of interaction with the resin and consequently G′ values were low, whereas G′ values for functionalized MWCNTs (amino and oxidised) were higher due to increased resin-nanotube interactions. Three approaches used to obtain rheological percolation thresholds showed values to increase in an order reflecting the improved MWCNT dispersion imparted by functionalisation. Analysis using colloidal dispersion theory fitted better with the experimental data than statistical percolation theory, and more closely mirrors the clustering of MWCNT agglomerates to form a percolated network. In fracture studies, toughness decreased with AR-MWCNT addition whereas for functionalised MWCNT addition toughness increased. For AR-MWCNT nanocomposites large agglomerates were formed which reduced toughness. In contrast, functionalised MWCNTs exhibited pull-out and fracture and formed smaller agglomerates which toughened the matrix via crack-deflection and pinning.

      PubDate: 2017-12-13T08:00:47Z
       
  • Impedance spectroscopy as a tool for moisture uptake monitoring in
           construction composites during service
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Sotirios A. Grammatikos, Richard J. Ball, Mark Evernden, Ryan G. Jones
      This is a first study comparing dielectric spectroscopy and gravimetric measurements of moisture uptake in pultruded glass fibre reinforced polymers (FRPs). Specimens were subjected to sub-Tg hygrothermal aging for 224 days. Impedance spectra in the frequency range 0.1 Hz to 10 MHz were captured during exposure and compared with gravimetric measurements. Moisture concentration was found to increase the FRP’s dielectric permittivity monotonically and decrease bulk resistance. High quality dielectric data was obtained as moisture uptake is independent of inherent changes suggested by mass loss which compromise gravimetry. Dielectric measurements remained sensitive to moisture despite significant mass loss, which typically distorts the weight gain process complicating the commonly adopted gravimetric methodology. Real-time dielectric measurements were obtained from FRP specimens continuously immersed in water and without making use of any additional sensing elements. The novel approach adopted is of high commercial impact as moisture uptake control is recognized as a significant problem by industry.

      PubDate: 2017-12-13T08:00:47Z
       
  • A particular interfacial strategy in PVDF/OBC/MWCNT nanocomposites for
           high dielectric performance and electromagnetic interference shielding
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Xiang-Jun Zha, Jun-Hong Pu, Li-Feng Ma, Ting Li, Rui-Ying Bao, Lu Bai, Zheng-Ying Liu, Ming-Bo Yang, Wei Yang
      Multi-walled carbon nanotubes (MWCNTs) were easily dispersed at the interface of polyvinylidene difluoride (PVDF) and ethylene-α-octene block copolymer (OBC) blend by melt compounding and the nanocomposites exhibited enhanced dielectric performance, electromagnetic interference shielding effectiveness (EMI SE) and balanced mechanical performance. Through the simple, efficient and scalable interfacial strategy to disperse MWCNTs at the interface of PVDF and OBC phases, the accumulation of charge carriers at the interfaces and strong interfacial polarization effect can be achieved. At low frequency, PVDF/OBC/MWNCT nanocomposite exhibits high dielectric permittivity (753.8) and low dielectric loss tangent (0.8), offering great potential in energy storage applications. Simultaneously, in X-band range, PVDF/OBC/MWNCT nanocomposite shows high EMI SE of around 34 dB which is higher than the industrial requirement when the content of MWCNTs is as low as 2.7 vol.%. This study provides possibilities to realize high-performance polymer nanocomposites via the particular interfacial structure through one-step melt processing.
      Graphical abstract image

      PubDate: 2017-12-13T08:00:47Z
       
  • Microstructure, microhardness and thermal expansion of CNT/Al composites
           prepared by flake powder metallurgy
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Pham Van Trinh, Nguyen Van Luan, Doan Dinh Phuong, Phan Ngoc Minh, Alicia Weibel, David Mesguich, Christophe Laurent
      Carbon nanotube/aluminum (CNT/Al) composites are prepared by a combination of flake powder metallurgy and hot-isostatic-pressing. The specimens are investigated by several techniques including Raman spectroscopy, optical microscopy, scanning- and transmission electron microscopy. The composites show a layered-microstructure with a stacking of CNT/Al flakes with a CNT-rich layer between two flakes. The individual Al grains forming the flakes are about 500 nm in size. The CNTs are well dispersed within a flake and they bridge the micro-cracks. The results reveal that the coefficient of thermal expansion (CTE) decreases markedly upon the increase in carbon content, reaching 15.4 × 10−6 K−1 for the specimen with a carbon content of 2.0 wt% (2.9 vol%), i.e. a 30% decrease compared to the CTE of pure Al. This could arise from the layered-microstructure resulting from the utilization of Al flakes as opposed to rounded particles.

      PubDate: 2017-12-13T08:00:47Z
       
  • Health monitoring of scarfed CFRP joints under cyclic loading via
           electrical resistance measurements using carbon nanotube modified adhesive
           films
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Till Augustin, Julian Karsten, Benedikt Kötter, Bodo Fiedler
      This study deals with a structural health monitoring approach for adhesively bonded carbon fiber reinforced polymer joints. A modification of an epoxy based adhesive film with single wall carbon nanotubes allows for electrical resistance measurements through the joint. Cyclic fatigue tests of adhesively bonded scarf joints with simultaneous electrical resistance measurements are conducted to investigate the damage detection and localization of repaired composite parts during operation. The measured electrical resistance changes are compared to results from digital image correlation. Crack initiation and growth can be detected by an increase of electrical resistance. Furthermore, it is possible with parallel oriented ink-jet printed circuits to localize the damages occurred.

      PubDate: 2017-12-13T08:00:47Z
       
  • Effect of polycarbonate film surface morphology and oxygen plasma
           treatment on mode I and II fracture toughness of interleaved composite
           laminates
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Xin Qian, Oleksandr G. Kravchenko, Diego Pedrazzoli, Ica Manas-Zloczower
      Polycarbonate (PC) offers excellent impact resistance, high elongation at break and high glass transition temperature making it a candidate for toughening composite laminates. Therefore, PC films were selected to interleave bi-directional glass fiber (GF)/epoxy composites to study mode I and mode II interlaminar fracture toughness. PC films with smooth and textured surface finishes and oxygen plasma treatment were used to examine their effect on composite toughening using double cantilever beam and end notched flexure tests for mode I and II interlaminar fracture toughness characterization, respectively. Oxygen plasma functionalization improved wetting and adhesive bonding of PC film with epoxy. Increase up to 71% in mode I and 42% in mode II interlaminar fracture toughness for interleaved composites was measured. The microscopic observations of fractured surfaces indicate that improved toughness in the case of PC interleaves is related to promoting cohesive-adhesive failure of the film, providing additional energy dissipating mechanisms during delamination propagation. Dynamic mechanical analysis revealed that PC films are able to preserve high operational temperature of composite.

      PubDate: 2017-12-13T08:00:47Z
       
  • Processability and tensile performance of continuous glass fiber/polyamide
           laminates for structural load-bearing applications
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): M. Nikforooz, M. Golzar, M.M. Shokrieh, J. Montesano
      The performance of continuous E-glass/polyamide 6 laminates processed using distinct hot press moulding cycles was assessed and compared with similar E-glass/epoxy and E-glass/polypropylene laminates. The effects of peak processing temperature, preheating time, and temperature dwell time on laminate consolidation and quality were observed using optical and scanning electron microscopy. Corresponding quasi-static tensile tests were performed on [0]8, [90]8, [02/902]s, [04/904]s and [±45]2s laminates. Compared to E-glass/epoxy composites, the [0]8 specimens presented a similar strength, while the [90]8 specimens exhibited a much lower strength due to weaker fiber/matrix adhesion. Conversely, the E-glass/polyamide cross-ply laminates had a markedly higher strength while exhibiting the same modulus. This is because of higher toughness; the polyamide matrix provides as was proved by higher transverse matrix cracking strain of E-glass/polyamide. These findings support the feasibility of producing cost-effective and high-quality E-glass/polyamide laminates for use in high-performance applications, which is an attractive alternative to more conventional glass/epoxy laminates.

      PubDate: 2017-12-13T08:00:47Z
       
  • A dissipative constitutive model for woven composite fabric under large
           strain
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Y. Denis, E. Guzman-Maldonado, N. Hamila, J. Colmars, F. Morestin
      Draping composite reinforcement on non-developable shapes necessarily leads to deformations in the plane generating large shears between warp and weft. Sliding between fibers and between yarns creates friction that dissipates energy. This paper presents a constitutive model describing the dissipative behaviour of 2D composite textile reinforcements under large strain. The model is based on two innovative points. First, the additive decomposition of Green-Naghdi is considered, which leads to write the yield function and the plastic law in a conventional manner, which is very uncommon for anisotropic fields. Secondly, nested surfaces according with Mroz Theory define the strong non-linearity of the problem. The use of these two points allows to define a flexible dissipative model for numerical simulations. The dissipation process driven by fibers friction is exclusively associated with the in-plane shear deformation mode. As a result, the material parameters are calibrated using standard methods, like the Picture Frame.

      PubDate: 2017-12-13T08:00:47Z
       
  • Predicting the Compression-After-Impact (CAI) strength of damage-tolerant
           hybrid unidirectional/woven carbon-fibre reinforced composite laminates
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Haibao Liu, Brian G. Falzon, Wei Tan
      The evaluation of Compression-After-Impact (CAI) strength is of great significance in the design of composite aerostructures. This paper presents a model for the numerical simulation of Compression-After-Impact (CAI) of hybrid unidirectional (UD)/woven carbon-fibre reinforced composite laminates. This three-dimensional damage model is based on Continuum Damage Mechanics (CDM) and Linear Elastic Fracture Mechanics (LEFM), implemented as a user defined material subroutine (VUMAT) in Abaqus/Explicit. This model, which accounts for interlaminar and intralaminar damage, and load reversal, incorporates a non-linear shear profile to account for matrix plasticity. Two different composite laminate lay-ups with varying extent of initial impact damage were tested to validate the computational model and enable a quantitative study of the influence of using woven plies on the surfaces of a laminate. Woven surface plies are often used in composite aerostructures to mitigate damage during drilling and constrain the extent of damage during low velocity impact. Good correlation was obtained between physical testing and simulation results, which establishes the capability of this damage model in predicting the structural response of composite laminates. The fully validated model was used to compare the CAI strength of an equivalent UD-only carbon-fibre reinforced composite laminate. The results showed that the hybrid unidirectional (UD)/woven laminate had a marginally higher strength (+3.3%) than the equivalent unidirectional (UD)-only laminate.

      PubDate: 2017-12-13T08:00:47Z
       
  • Electrical and thermal conductivities of MWCNT/polymer composites
           fabricated by selective laser sintering
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Shangqin Yuan, Yun Zheng, Chee Kai Chua, Qingyu Yan, Kun Zhou
      Additive manufacturing such as selective laser sintering (SLS) offers the strategies to create 3D complex components with desirable mechanical, electrical and thermal properties using the composite powders as feeding materials. This work proposes a new fabrication approach to preparing carbon nanotube (CNT) composite powders and utilizes them for SLS process. As compared with the hot-compression process, the SLS process could offer an effective method to fabricate the CNT/Polymer composite with electrically conductive segregated structures. At a small loading range of CNTs (<1 wt%), the laser-sintered composites exhibit significant improvements in the electrical conductivity up to anti-static and conductive range qualifying the applications in automobile and aerospace. However, the enhancement in thermal conductivity of laser-sintered composites is not comparable with that of hot-compressed ones. The process-structure-property relationships are further investigated to study the different processes induced microstructures and the underlying mechanism of thermal and electrical performances.

      PubDate: 2017-12-13T08:00:47Z
       
  • Constructing three-dimensionally interwoven structures for ceramic/polymer
           composites to exhibit colossal dielectric constant and high mechanical
           strength: CaCu3Ti4O12/epoxy as an example
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Xiaoqiang You, Nan Chen, Guoping Du
      Until now, the reported dielectric constants of the ceramic/polymer composites are rather low, even though their corresponding bulk ceramics have colossal dielectric constants. This work demonstrates that ceramic/polymer composites can achieve colossal dielectric constants by constructing three-dimensionally interwoven structures. Furthermore, the ceramic/polymer dielectric composites exhibit high mechanical strength. As an example, CaCu3Ti4O12/epoxy dielectric composites with such interwoven structures are fabricated in this work. The CaCu3Ti4O12/epoxy composites exhibit both colossal dielectric constant and high flexural strength, both of which rapidly increase with the CaCu3Ti4O12 content. When the CaCu3Ti4O12 content is about 57.7 vol%, the dielectric constant and flexural strength of the CaCu3Ti4O12/epoxy composites are about 1501 at 1 MHz and 118.8 MPa, respectively. Their dielectric constants are much higher than the predicted values by the existing theoretical models for ceramic/polymer dielectric composites. A modified parallel model is proposed to explain the presence of colossal dielectric constants of the ceramic/polymer composites.

      PubDate: 2017-12-13T08:00:47Z
       
  • Fabrication of ZrP nanosheet decorated macromolecular charring agent and
           its efficient synergism with ammonium polyphosphate in flame-retarding
           polypropylene
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Huali Xie, Xuejun Lai, Hongqiang Li, Xingrong Zeng
      Poor efficiency is one of the biggest challenges for halogen-free flame retardant polymer. Catalyzing the carbonization of polymer itself during combustion is proposed to be a promising way to address this issue. In this work, a novel macromolecular charring agent (MCA) decorated by zirconium phosphate nanosheet named ZrP-d-MCA was synthesized and characterized. Subsequently, it was combined with ammonium polyphosphate (APP) to reduce the flammability of polypropylene (PP). When the contents of ZrP-d-MCA and APP were 5 wt% and 15 wt%, respectively, PP/Zr-d-MCA/APP could reach a limiting oxygen index of 32.5% and achieve UL-94 V-0 rating. Moreover, the bench-scale combustion performance determined by the cone calorimeter was significantly improved. The flame-retardant mechanism of ZrP-d-MCA/APP was revealed: during combustion, ZrP nanosheet could efficiently catalyze the charring reactions of MCA to form closed micro-nano char-cages, in which the degradation products of PP would be trapped and catalyzed into thermostable graphitization char.

      PubDate: 2017-12-13T08:00:47Z
       
  • Friction stir welding/processing of polymers and polymer matrix composites
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Yongxian Huang, Xiangchen Meng, Yuming Xie, Long Wan, Zongliang Lv, Jian Cao, Jicai Feng
      Friction stir welding/processing (FSW/P) involving temperature, mechanics, metallurgy and interaction, is a complex solid state joining and processing technology. FSW has been widely applied to join aluminum alloy, titanium alloy and other materials which are difficult to weld by fusion welding. The last scientific study states that FSW has potential to join thermoplastic polymers and polymer matrix composites. In this review, current understanding and development about FSW of thermoplastic polymers and polymer matrix composites, multifunctional composites fabrication as well as dissimilar FSW of metal and polymer are reviewed. Future scientific research and engineering development related to FSW/P of thermoplastic polymers and polymer matrix composites are identified.

      PubDate: 2017-12-13T08:00:47Z
       
  • Reinforcement of economical and environment friendly Acacia catechu
           particles for the reduction of brittleness and curing temperature of
           polybenzoxazine thermosets
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Abdul Qadeer Dayo, Rui-kun Ma, Sadia Kiran, Abdeldjalil Zegaoui, Wan-an Cai, Ahmer Hussain Shah, Jun Wang, Mehdi Derradji, Wen-bin Liu
      The brittleness always remained a major concern for the polybenzoxazine thermosets. Several attempts have been made to overcome the brittleness issue, but all find some kind of sacrificing in other properties. A new and economical approach is presented by the reinforcement of catechin-rich Acacia catechu (AC) particles. The micro size AC particles blended with bisphenol-A aniline-based benzoxazine (BA-a) resin and isothermally cured. The terminal OH groups of produced tannic acid participated in the curing process and helped in the ring opening of BA-a resin. The composites exhibited that the brittleness of polybenzoxazine has been improved by 35%, simultaneously its strength, Youngs’ modulus, stiffness, glass transition temperature, and thermal stabilities are also enhanced. The highest impact strength of the composite is observed on only 4 wt% loading of AC particles and read as 5.2 ± 0.16 kJ/m2, 307.1% higher than the value of neat poly(BA-a).

      PubDate: 2017-12-13T08:00:47Z
       
  • Multi-scale design of novel materials for emerging challenges in active
           thermal management: Open-pore magnesium-diamond composite foams with
           nano-engineered interfaces
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): J.M. Molina-Jordá
      Open-pore Mg foams, which have been traditionally discarded for heat dissipation applications given their low thermal conductivity values, can prove appealing materials for active thermal management if they incorporate diamond particles coated with a nano-dimensioned layer of TiC. These composite foam materials can be manufactured by the replication method, conveniently adapted to Mg, that requires a strict multi-scale control: correct distribution of structural constituents (pores, diamond and Mg) on the meso-/micro-scale ensures homogeneity and complete pore connectivity, while a proper nanoscale control of the TiC coating on diamond particles achieves high thermal conductance at the interface between diamond particles and Mg. The manufactured Mg-diamond foam materials attain outstanding thermal conductivity values (up to 82 W/m K) and maximum heat dissipation performance, tested on active convective cooling, almost two times higher than their equivalent magnesium foams and twenty per cent superior to that of conventional aluminium foams.

      PubDate: 2017-12-13T08:00:47Z
       
  • Long-term performance of β-nucleated toughened
           polypropylene-biocarbon composites
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Ehsan Behazin, Arturo Rodriguez-Uribe, Manjusri Misra, Amar K. Mohanty
      Thermoplastic polyolefins or TPOs are of widespread use in the automotive industry. In this study, the long-term performance of biocarbon based TPOs is investigated for the first time. The durability of these bio-based composites with and without hindered phenolic antioxidants was investigated under accelerated heat aging for 1000 h. Thermo-oxidative degradation was tracked along the specimen’s thickness using energy dispersive spectroscopy. Performance of the biocomposites was gauged by Izod notched impact and tensile properties. Microstructural changes were monitored by differential scanning calorimetry and dynamic mechanical analysis. While the tensile properties were sufficiently sustained using the antioxidants after this test, the impact strength failed to retain initial values. The morphological changes in the β crystal phase were recognized as the primary factor in the reduction of the impact strength of the biocomposites.

      PubDate: 2017-12-13T08:00:47Z
       
  • The enhancement effect of carbon-based nano-fillers/polyaniline hybrids on
           the through-thickness electric conductivity of carbon fiber reinforced
           polymer
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Xiuyan Cheng, Tomohiro Yokozeki, Lixin Wu, Jun Koyanagi, Haopeng Wang, Qingfu Sun
      Overall goal of this research is to study the conductivity enhancement effect and its mechanism for different types of carbon-based nano-fillers/conduct polymer hybrids in carbon fiber reinforced polymer (CFRP). Multi-walled carbon nanotubes (MWCNT)/polyaniline (PANI) and graphene oxide (GO)/PANI hybrids were separately dispersed into divinylbenzene (DVB) to make the CFRP composites. The alternating current (AC) electrical conductivity results show that both, the binary MWCNT/PANI and GO/PANI hybrids have significant enhancement on AC conductivity, while MWCNT/PANI gives better improvement over GO/PANI hybrids. The mechanism for the conductivity enhancement was studied by SEM, XRD, UV–Vis and nanoindentor. Circuit models were proposed. The maximum AC conductivity of CFRP made of MWCNT/PANI was measured to be 22.4 S/m, which has been found to be enhanced by more than 3 orders of magnitude compared to CF/DVB. Thus, CF/MWCNT-PANI composites can be considered to be promising candidates for multifunctional material where high conductivity is demanded.

      PubDate: 2017-12-13T08:00:47Z
       
  • Highly sensitive and stretchable piezoresistive strain sensor based on
           conductive poly(styrene-butadiene-styrene)/few layer graphene composite
           fiber
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Xingping Wang, Si Meng, Mike Tebyetekerwa, Yilong Li, Jürgen Pionteck, Bin Sun, Zongyi Qin, Meifang Zhu
      High stretchability and sensitivity are the major desired requirements of strain sensors for wearable electronics applications, especially in health and medical monitoring. Herein, a highly sensitive and stretchable strain sensor based on conductive poly(styrene-butadienestyrene)/few layer graphene (SBS/FLG) composite fiber is fabricated through an easy and scalable wet-spinning process. Owing to the super flexibility of SBS matrix and the excellent electrical and mechanical properties of FLG, the SBS/FLG fiber based strain sensor revealed superior performance, including wide workable strain range (>110%), superior sensitivity (gauge factor of 160 at a strain of 50% and of 2546 at a strain of 100%), and durability. Furthermore, the mechanism behind the excellent performances of SBS/FLG fiber based sensors is discussed in detail.

      PubDate: 2017-12-13T08:00:47Z
       
  • Passive control of wrinkles in woven fabric preforms using a geometrical
           modification of blank holders
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): A. Rashidi, A.S. Milani
      Textile preforms have become materials of choice in numerous modern industries, partly due to their superior conformability onto complex 3D mould shapes. Maximum formability of this category of composite reinforcements, however, is still limited by defects such as wrinkling, which remains a challenging issue for composite designers during optimization of thermo-stamping operations. The aim of this article is to gain a deeper understanding of the effect of blank holding boundary condition on the extent of wrinkling as well as other local defects such as tow slippage and yarn jamming, and thereby to introduce a passive defect mitigation approach via geometrical modification of the blanks. To verify the applicability of the approach, a series of hemisphere forming experiments under unmodified and modified forming boundary conditions have been performed and compared on both single and multiple ply lay-ups, using a comingled polypropylene/E-glass thermoplastic plain weave.

      PubDate: 2017-12-13T08:00:47Z
       
  • Transverse shear modulus of unidirectional composites with voids estimated
           by the multiple-cells model
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Jui-He Tai, Autar Kaw
      Voids are inevitably formed as a by-product during manufacturing processes of composite materials and affect many of its mechanical properties including the transverse shear modulus. Although several analytical and empirical models are available for transverse shear modulus, they are based on simple assumptions, and none of them consider the effect of voids. In this work, we estimate transverse shear modulus through a finite element model that uses multiple-cells and three-dimensional analysis. The effect of voids on the transverse shear modulus is studied through a design of experiment approach via three primary parameters: fiber-to-matrix Young’s moduli ratio, fiber volume fraction, and void volume fraction. The results indicate that for allowable void volume fractions, the transverse shear modulus can decrease by as much as 15%, while the fiber volume fraction is the most dominating factor of the three in influencing its value.

      PubDate: 2017-12-13T08:00:47Z
       
  • Process-induced fiber matrix separation in long fiber-reinforced
           thermoplastics
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): S. Goris, T.A. Osswald
      This work explores the fiber migration during injection molding of long glass fiber-reinforced polypropylene. It was found that the simplified assumption of uniform fiber concentration distribution is inaccurate, and the process causes substantial variations in the fiber concentration along the flow path and through the thickness of injection molded parts. This was tested for a simple plate geometry molded at varying nominal fiber concentrations. The fiber concentration was measured by pyrolysis to obtain a global concentration, and using micro computed-tomography for a through-thickness analysis. Additionally, the fiber concentration at the melt front of partially filled moldings was investigated. A new measurement protocol using micro computed-tomography and digital image processing is proposed to calculate the through-thickness fiber concentration. The results of this study show substantial heterogeneity of the fiber concentration throughout the molded plates. Fibers agglomerated in the core layer with volume fractions up to 1.5 times the nominal fiber concentration.

      PubDate: 2017-12-13T08:00:47Z
       
  • Healing Mechanisms Induced by Synergy of Graphene-CNTs and Microwave
           Focusing Effect for the Thermoplastic Polyurethane Composites
    • Abstract: Publication date: Available online 11 December 2017
      Source:Composites Part A: Applied Science and Manufacturing
      Author(s): Yunbo Luan, Feilong Gao, Yongcun Li, Jinglei Yang, Yinchun Hu, Zhangxin Guo, Zhihua Wang, Aijuan Zhou
      Healing is a vital factor of polymer materials. Herein, an investigation on the healing performance of Graphene-CNTs reinforced thermoplastic polyurethane (TPU) composites induced by microwave was carried out. The results show that the graphene sheet and CNTs formed a combined structure of Graphene-CNTs. This Graphene-CNTs may have a synergy effect on the coupling between microwave and Graphene-CNTs on the interface, and promote the fully healing of damaged composites. The tensile strength of the healed composites even exceeds the value of the virgin specimens. Simultaneously, there is a microwave focusing effect within the region of crack, and on the surfaces of graphene or CNTs that exposed on the fracture surfaces. This effect will also promote the healing of damaged composites, and can realize the preferential healing of crack as compared with the non-damaged regions. These results may help us to get a deeper understanding of healing mechanisms of some thermoplastic composites.

      PubDate: 2017-12-13T08:00:47Z
       
  • Tailoring Viscoelastic Response, Self-heating and Deicing Properties of
           Carbon-Fibre Reinforced Epoxy Composites by Graphene Modification
    • Abstract: Publication date: Available online 8 December 2017
      Source:Composites Part A: Applied Science and Manufacturing
      Author(s): Jamal Seyyed Monfared Zanjani, Burcu Saner Okan, Panagiotis-Nektarios Pappas, Costas Galiotis, Yusuf Ziya Menceloglu, Mehmet Yildiz
      Vacuum infusion process was employed for the fabrication of carbon fiber reinforced polymeric composites modified by graphene. Three different methods were utilized for the incorporation of graphene into the CFRP composites. In the first and second approaches, graphene were respectively electrosprayed on the surface of carbon fibers as interface modifiers and dispersed into the epoxy resin to improve the matrix properties. The third method includes the concurrent usage of both treatments just mentioned above. The viscoelastic behavior of composites was examined by dynamical mechanical testing at different temperatures, frequencies and graphene integration configurations. In addition, the effect of graphene on the electrical conductivity, thermal diffusivity and electro-thermal performance of composites was also studied in detail. The results indicated that the FRP composites gain multi-functionality while preserving their mechanical integrity for all graphene integration configurations with significant improvements when graphene is used simultaneously as the interface modifier and the matrix reinforcement.

      PubDate: 2017-12-13T08:00:47Z
       
  • THE electric field alignment of short carbon fibres to enhance the
           toughness of epoxy composites
    • Abstract: Publication date: Available online 7 December 2017
      Source:Composites Part A: Applied Science and Manufacturing
      Author(s): Anil R. Ravindran, Raj B. Ladani, Shuying Wu, Anthony J. Kinloch, Chun H. Wang, Adrian P. Mouritz
      An investigation is presented on increasing the fracture toughness of epoxy/short carbon fibre (SCF) composites by alignment of SCFs using an externally applied alternating current (AC) electric field. Firstly, the effects of SCF length, SCF content and AC electric field strength on the rotation of the SCFs suspended in liquid (i.e. uncured) epoxy resin are investigated. Secondly, it is shown the mode I fracture toughness of the cured epoxy composites increases with the weight fraction of SCFs up to a limiting value (5 wt.%). Thirdly, the toughening effect is greater when the SCFs are aligned in the composite normal to the direction of crack growth. The SCFs increases the fracture toughness by inducing multiple intrinsic and extrinsic toughening mechanisms, which are identified. Based on the identified toughening mechanisms, an analytical model is proposed to predict the enhancement to the fracture toughness due to AC electric field alignment of the SCFs.

      PubDate: 2017-12-13T08:00:47Z
       
  • High thermal conductivity and stretchability of layer-by-layer assembled
           silicone rubber/graphene nanosheets multilayered films
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Jianan Song, Caibao Chen, Yong Zhang
      Thermally conductive silicone rubber composites used for heat removal from electronic devices have attracted great attention. A facile spin-assisted layer-by-layer assembly approach was used to fabricate highly thermally conductive multilayered silicone rubber/graphene films. The films exhibit highly ordered lamellar structure with the high orientation of graphene which provides continuous thermally conductive pathways in horizontal direction. A multilayered film with 40 assembly cycles has the thermal conductivity of 2.03 W/(m·K) in in-plane direction. Moreover, the film can be highly twisted to any angle and has the elongation at break of 325%, which is rarely achieved in previously reported graphene-based multilayered films. Even up to 500 stretch-recovery cycles at 50% strain, the change of the thermal conductivity was negligible, indicating the high durability, excellent flexibility and stretchability of the film. The films with high thermal conductivity and stretchability have potential applications in flexible electronics, wearable devices and electronic skin.

      PubDate: 2017-11-16T10:31:49Z
       
  • Synergistic effects of spray-coated hybrid carbon nanoparticles for
           enhanced electrical and thermal surface conductivity of CFRP laminates
    • Abstract: Publication date: February 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 105
      Author(s): Yan Li, Han Zhang, Yi Liu, Huasheng Wang, Zhaohui Huang, Ton Peijs, Emiliano Bilotti
      Carbon fibre reinforced plastics (CFRPs) are intensively used in modern aircraft structures because of their superb specific mechanical properties. Unfortunately their electrical and thermal conductivities are not sufficiently high for some applications like electromagnetic interference (EMI) shielding and lighting strike protection (LSP). The addition of external metallic structures, such as aluminium or copper mesh, is generally required with a compromise in terms of increased mass and manufacturing cost as well as reduced corrosion resistance. In the present work spray coating of carbon nanoparticles was utilized as a simple method to locally increase the electrical and thermal suface conductivity of CFRPs. The combined use of carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) synergistically reduced the CFRPs surface resistivity by four orders of magnitude (from 2–3 Ω/sq to 3 × 10−4 Ω/sq) and increased the thermal conductivity by more than 7 times (from 200 W m−1 K−1 to 1500 W m−1 K−1), opening up possibilities for the replacement of metallic mesh structures for EMI shielding and LSP. An analytical model was introduced based on a one-dimensional heat conduction approach to predict the effective thermal conductivity for the hybrid nanofiller coating layer and its findings showed good agreement with experimental data.

      PubDate: 2017-11-16T10:31:49Z
       
  • Single Fiber Pull-Out Test of Regenerated Cellulose Fibers in
           Polypropylene: An Energetic Evaluation
    • Abstract: Publication date: Available online 7 November 2017
      Source:Composites Part A: Applied Science and Manufacturing
      Author(s): J.-C. Zarges, C. Kaufhold, M. Feldmann, H.-P. Heim
      This paper focuses on the energetic evaluation of the single fiber pull-out test (SFPT) using regenerated cellulose fibers (RCF) in a PP matrix with a varying MAPP content. Glass fibers were used for reference purposes. By means of the SFPT the interfacial shear strength (IFFS), the critical fiber length (lc), the consumed energy of a fiber pull-out and the consumed energy of a fiber rupture were determined. Results were related to the fiber length distribution in injection molded specimens. It was shown that theoretically more fiber ruptures appear in composites with RCF than with GF. But RCF composites offer a larger number of long fibers, slightly underneath the critical fiber length, consuming a high amount of energy by being pulled out at a composite failure. The consumed energy of a fiber pull-out per length was increased by using MAPP but simultaneously the critical fiber length was significantly reduced.

      PubDate: 2017-11-09T08:38:53Z
       
  • Microcellular PP/GF composites: Morphological, mechanical and fracture
           characterization
    • Abstract: Publication date: January 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 104
      Author(s): J. Gómez-Monterde, M. Sánchez-Soto, M. Ll. Maspoch
      The aim of the present work is to analyze the morphology, mechanical properties and fracture behaviour of solid and foamed plates made of glass fiber-reinforced PP. The morphology exhibited a solid skin/foamed core structure, dependent on the foaming ratio. Simulation of the microcellular injection molding process with Moldex 3D® software provided a good approach to the experimental results. The flexural properties and impact resistance showed lower values as the apparent density decreased, but constant specific properties. The fracture characterization was carried out by determining the Crack Tip Opening Displacement (CTOD) at low strain rate, as well as the fracture toughness (KIc ) at impact loading. Foamed specimens presented higher values of CTOD than the solid ones and higher as the foaming ratio increases, due to cells acting as crack arrestors by blunting the crack tip. However, the fracture toughness KIc decreased with decreasing the apparent density. Anisotropy due to fiber orientation was also observed. Fibers were aligned in the filling direction in the surface layers, while they were oriented in the transverse direction in the core. According to the amount of fibers oriented in one direction or another, different properties were obtained.

      PubDate: 2017-11-02T03:11:49Z
       
  • Micro-CT measurement of fibre misalignment: Application to carbon/epoxy
           laminates manufactured in autoclave and by vacuum assisted resin transfer
           moulding
    • Abstract: Publication date: January 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 104
      Author(s): Nghi Q. Nguyen, Mahoor Mehdikhani, Ilya Straumit, Larissa Gorbatikh, Larry Lessard, Stepan V. Lomov
      This paper proposes a methodology for measurement of fibre misalignment in composite laminates based on the structure tensor of fibre orientations extracted from X-ray micro-computed tomography (micro-CT) images. The methodology is applied to carbon fibre/epoxy composites manufactured with two technologies: (1) by prepregging and consolidation in an autoclave and (2) by vacuum assisted resin transfer moulding. The results show that the in-plane inter-ply misalignment of fibres in the prepreg laminate and in the infusion-produced laminate is within 2–4° and 1–2°, respectively. The misalignment results allow better understanding of the manufacturing typical fibre orientation precision level for the low pressure (vacuum assisted resin transfer moulding) and high pressure (autoclave) manufacturing.

      PubDate: 2017-11-02T03:11:49Z
       
  • Enhanced dielectric properties through using mixed fillers consisting of
           nano-barium titanate/nickel hydroxide for polyvinylidene fluoride based
           composites
    • Abstract: Publication date: January 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 104
      Author(s): Yan Yang, Zhongyuan Li, Wenjing Ji, Chengxiao Sun, Hua Deng, Qiang Fu
      The dispersion of nano-barium titanate(NBT) in polyvinylidene fluoride(PVDF) is one of the key issues in dielectric composites. Various NBT surface modification strategies which suffer from complex process and small-scale production have been reported. Herein, in-situ synthesized three-dimensional Ni(OH)2 is introduced to improve NBT dispersion in PVDF. During hydrothermal reaction, NBT aggregates are dispersed on the petals of in-situ grown Ni(OH)2 crystals as small aggregates. The three-dimensional structure of Ni(OH)2 can act as physical barrier to prohibit secondary agglomeration in PVDF to allow rather uniform NBT dispersion. Meanwhile, these hydroxyl groups on Ni(OH)2 ensures good interaction between filler and PVDF, and trigger β crystals. Comparing with NBT/PVDF containing the same amount of filler(2.5 wt%), the breakdown strength and maximum energy density containing mixed filler increases 14% and 70%, reach 282.6 KV/mm and 6.13 J cm−3, respectively. This study provides a new approach to uniformly disperse nanofillers in polymer for enhanced dielectric properties.

      PubDate: 2017-11-02T03:11:49Z
       
  • Hybrid welding of carbon-fiber reinforced epoxy based composites
    • Abstract: Publication date: January 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 104
      Author(s): Francesca Lionetto, Maria Nicolas Morillas, Silvio Pappadà, Giuseppe Buccoliero, Irene Fernandez Villegas, Alfonso Maffezzoli
      The approach for joining thermosetting matrix composites (TSCs) proposed in this study is based on the use of a low melting co-cured thermoplastic film, added as a last ply in the stacking sequence of the composite laminate. During curing, the thermoplastic film partially penetrates in the first layer of the thermosetting composite, leading to macro-mechanical interlocking as the main connection mechanism between the thermoplastic film and the underlying composite. After curing, the thermosetting composite joints with the thermoplastic modified surface can be assembled by welding. Welding of the TSC-TSC joints is performed by ultrasonic and induction welding. The weld strength is investigated by morphological characterization of cross sections and failure surfaces and by mechanical testing. The effect of the thermoplastic film thickness on the welding process and on its outcome is also analyzed. Both induction and ultrasonic welding mostly result in good-quality welded joints. The welding process used as well as the initial thickness of the thermoplastic film are found to have a significant effect on the final thickness of the weld line and on the location of failure. Thicker thermoplastic films are found to ease the welding processes.

      PubDate: 2017-11-02T03:11:49Z
       
  • Failure mechanisms and damage evolution of laminated composites under
           compression after impact (CAI): Experimental and numerical study
    • Abstract: Publication date: January 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 104
      Author(s): X.C. Sun, S.R. Hallett
      The damage tolerance of Carbon Fibre Reinforced Polymer (CFRP) to Barely Visible Impact Damage (BVID) is a critical design limiter for composite structures. This study investigated the key driving mechanisms and damage evolution of the compressive failure of laminated composites containing BVID using compression after impact and indentation (CAI) tests. Experiments were carried out on two similar quasi-isotropic laminates: [452/902/02/−452]2S and [45/90/0/−45]4S. Matrix cracking and delaminations were introduced by either low-velocity impact or quasi-static indentation tests prior to the CAI tests. The full-field displacement during CAI as well as the moment of rupture was captured by 3D Digital Image Correlation (DIC). The effect of ply-blocking and influence of factors, such as impact energy, delamination area and surface indentation, on compressive failure was studied. Previously validated high-fidelity finite element (FE) numerical models for the indentation and impact events were then used to investigate the damage evolution during CAI failure.

      PubDate: 2017-11-02T03:11:49Z
       
  • Kinetics and temperature evolution during the bulk polymerization of
           methyl methacrylate for vacuum-assisted resin transfer molding
    • Abstract: Publication date: January 2018
      Source:Composites Part A: Applied Science and Manufacturing, Volume 104
      Author(s): Yasuhito Suzuki, Dylan Cousins, Jerred Wassgren, Branden B. Kappes, John Dorgan, Aaron P. Stebner
      Curing reactions of methyl methacrylate (MMA) comprise an induction time of gradual temperature change over tens of minutes, followed by a sudden temperature rise within tens of seconds because of auto-acceleration known as the Trommsdorff effect. These curing effects were investigated as initial initiator and polymer concentrations were varied. A mathematical model combining the reaction kinetics with heat transfer was developed and verified in its ability to simulate the processing kinetics and temperature evolutions throughout thick MMA-based parts. It was further demonstrated that the processing conditions at specific points within a part during manufacture could be actively controlled via the Trommsdorff effect by locally varying the initial concentration of poly(methyl methacrylate) (PMMA) solution. Together, these advancements provide an enhanced ability to design and optimize the manufacture of thick, large-scale PMMA materials by taking advantage of auto-acceleration instead of avoiding it.

      PubDate: 2017-11-02T03:11:49Z
       
 
 
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