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  Subjects -> ENGINEERING (Total: 2284 journals)
    - CHEMICAL ENGINEERING (192 journals)
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    - ELECTRICAL ENGINEERING (102 journals)
    - ENGINEERING (1208 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: 5)
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: 227)
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: 6)
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: 14)
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: 20)
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: 40)
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  
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: 3)
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: 3)
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: 7)
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: 4)
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: 256)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 179)
Composites Part B : Engineering     Hybrid Journal   (Followers: 227)
Composites Science and Technology     Hybrid Journal   (Followers: 197)
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: 29)
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 B : Engineering
  [SJR: 2.125]   [H-I: 75]   [227 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1359-8368
   Published by Elsevier Homepage  [3042 journals]
  • Performance assessment of basalt FRCM for retrofit applications on masonry
    • Abstract: Publication date: 1 November 2017
      Source:Composites Part B: Engineering, Volume 128
      Author(s): Gian Piero Lignola, Carmelo Caggegi, Francesca Ceroni, Stefano De Santis, Piotr Krajewski, Paulo B. Lourenço, Mattia Morganti, Catherine (Corina) Papanicolaou, Carlo Pellegrino, Andrea Prota, Luigia Zuccarino
      An increasing interest and application is nowadays found for composite systems in construction and rehabilitation industry. The consensus on fibre reinforced composite systems was mainly based on high tensile strength, light weight, relative ease of installation, and resistance to corrosion. However, some drawbacks related to the epoxy (hence, organic) matrices of Fiber-Reinforced Polymers (FRP) have been solved by inorganic ones yielding to novel fibre reinforced composites. In these materials the composite action is mainly achieved through mechanical interlock between the matrix (e.g. a cement- or a lime-based mortar or a geopolymer with the option of chopped fibres and/or low-content polymer addition) and the mesh-like fibrous structure (a textile) that allows the mortar to protrude through the grid's openings. Aiming at the investigation of the mechanical properties and the development of testing procedures for this new family of materials (termed herein as Fabric-Reinforced Cementitious Matrix (FRCM)) the present paper presents the results of an extensive experimental program on different combinations of basalt fibre textiles and inorganic matrices organized by RILEM TC 250-CSM (Composites for the Sustainable strengthening of Masonry) involving ten European laboratories. The tests involve more than 100 specimens: half are tensile tests and the other half are bond tests carried out on prisms made of clay bricks, on three different basalt-based FRCM configurations comprising readily available commercial systems provided by different producers. The scope of this work is aimed not only at presenting a comparative performance assessment of different Basalt FRCM systems, but also at providing meaningful criteria to reliably design and analyse retrofit applications. The relevant round robin test program provides valuable data generated during the experimental activity and statistical analysis thereof; then, based on the various testing approaches employed, the advantages/drawbacks of certain testing factors are summarized and critically assessed, reflecting the experience of involved institutions. It is believed that this represents a crucial step in improving knowledge on innovative retrofit applications and developing standard test methods.

      PubDate: 2017-07-11T17:09:52Z
       
  • Stability of magnetoactive composites with periodic microstructures
           undergoing finite strains in the presence of a magnetic field
    • Abstract: Publication date: 1 November 2017
      Source:Composites Part B: Engineering, Volume 128
      Author(s): Artemii Goshkoderia, Stephan Rudykh
      We investigate the macroscopic magnetomechanical instabilities in magnetorheological elastomer (MRE) composites undergoing finite strains in the presence of a magnetic field. In particular, we identify the unstable domains for MRE composites with periodically distributed circular and elliptical inclusions embedded in a soft matrix. We use the isotropic Langevin model for magnetic behavior, to account for the initial (linear) susceptibility and saturation magnetization of the magnetoactive inclusions. We analyze the influence of the applied magnetic field and finite strains, as well as particle shape and material properties, on the stability of the MRE composites. We find that the stable and unstable domains can be significantly tuned by the applied magnetic field, depending on deformation, microstructure and magnetic properties of the inclusions such as initial susceptibility and saturation magnetization.

      PubDate: 2017-07-11T17:09:52Z
       
  • Development of self-healing multifunctional materials
    • Abstract: Publication date: 1 November 2017
      Source:Composites Part B: Engineering, Volume 128
      Author(s): Liberata Guadagno, Carlo Naddeo, Marialuigia Raimondo, Giuseppina Barra, Luigi Vertuccio, Andrea Sorrentino, Wolfgang H. Binder, Martin Kadlec
      Reversible hydrogen bonds determined by interaction between epoxy resin and nanocages of polyhedral oligomeric silsesquioxane (POSS) compound have been employed to activate self-healing mechanisms integrated in thermosetting multifunctional materials. The phase composition of the multifunctional resin containing embedded multiwalled carbon nanotubes (MWCNT) can be advantageously exploited to enhance the healing efficiency up to 400%. The presence of MWCNT is responsible of a greater mobility of chains belonging to domains finely interpenetrated in the matrix where the reversible hydrogen bonds can provide enhanced healing efficiency.

      PubDate: 2017-07-11T17:09:52Z
       
  • New composites based on waste PET and non-metallic fraction from waste
           printed circuit boards: Mechanical and thermal properties
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Tihomir Kovačević, Jelena Rusmirović, Nataša Tomić, Milena Marinović-Cincović, Željko Kamberović, Miloš Tomić, Aleksandar Marinković
      Influence of the addition of three different non-metallic fractions (NMF), obtained by processing of printed circuit boards (PCBs), on the mechanical and thermal properties of unsaturated polyester resin (UPR) based composites were studied in this paper. UPR, based on products of PET depolymerization, and NMF were characterized using FTIR, NMR, optical microscopy and SEM/EDS analysis. Cross-linking density (ν), storage modulus (G′), damping factor (tanδ) and glass transition temperature (T g) of the composites were determined from the DMA testing. Tensile (σ t) and flexural (σ f) strength, and micro Vickers hardness indicated good composite performance under static load. Thermal and flame resistant properties were analyzed by TGA/DTG and UL-94 flammability test whereby V-2 category of appropriate composite was achieved. Composites with satisfactory mechanical and thermal properties reflected synergetic effect of constituents obtained from waste materials.

      PubDate: 2017-07-02T12:58:19Z
       
  • A method to determine composite material residual tensile strength in the
           fibre direction as a function of the matrix damage state after fatigue
           loading
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Damien Caous, Christophe Bois, Jean-Christophe Wahl, Thierry Palin-Luc, Julien Valette
      The phenomenon of residual strength in composite laminates after fatigue loading has been studied for decades but is generally expressed as a function of the number of cycles applied to the specimens. Phenomenological laws deduced from these tests are therefore loading dependent and identifying a valid model for any loading condition of a given laminate requires long fatigue testing campaigns. To overcome this difficulty, a testing procedure is proposed to express the residual tensile strength of a unidirectional ply in the fibre direction, as a function of its matrix damage. The resulting behaviour is then independent of the imposed loading and can be determined by only a few fatigue tests. Experimental results obtained on glass-epoxy non-crimp fabric laminates are presented and analysed.

      PubDate: 2017-07-02T12:58:19Z
       
  • Macro and nanoscale wear behaviour of Al-Al2O3 nanocomposites fabricated
           by selective laser melting
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Quanquan Han, Yanquan Geng, Rossitza Setchi, Franck Lacan, Dongdong Gu, Sam L. Evans
      Aluminium-based composites are increasingly applied within the aerospace and automotive industries. Tribological phenomena such as friction and wear, however, negatively affect the reliability of devices that include moving parts; the mechanisms of friction and wear are particularly unclear at the nanoscale. In the present work, pin-on-disc wear testing and atomic force microscopy nanoscratching were performed to investigate the macro and nanoscale wear behaviour of an Al-Al2O3 nanocomposite fabricated using selective laser melting. The experimental results indicate that the Al2O3 reinforcement contributed to the macroscale wear-behaviour enhancement for composites with smaller wear rates compared to pure Al. Irregular pore surfaces were found to result in dramatic fluctuations in the frictional coefficient at the pore position within the nanoscratching. Both the size effect and the working-principle difference contributed to the difference in frictional coefficients at both the macroscale and the nanoscale.
      Graphical abstract image

      PubDate: 2017-07-02T12:58:19Z
       
  • Epoxy-copper composites with gradation of filler content
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Józef Stabik, Agnieszka Dybowska
      The goal of this work was to study the structure and electrical properties of functional polymeric graded materials with epoxy resin matrix and copper powder as a filler. Gradation of the filler content and in this way gradation of electrical properties was obtained using centrifugal casting technology. Filler particles distribution in the matrix was controlled by changing casting parameters. Rotational velocity influenced particles distribution and electrical resistivity distribution the most significantly. Performed experiments showed that it is possible to control the structure of graded composites and in this way the gradation of electrical properties. Elaborated polymeric graded materials may be applied in many industrial fields where products with low surface electrical resistivity on one surface and high electrical resistivity in the rest of the volume are needed.

      PubDate: 2017-07-02T12:58:19Z
       
  • Residual strength evaluation after impact tests in extreme temperature
           conditions. New equipment for CAI tests
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Valentina Lopresto, Ilaria Papa, Antonio Langella
      A large experimental campaign has included low velocity falling weight tests at room and low temperatures, on carbon fibre laminates in vinylester resin, clamped following the EN6038 or ASTMD7136 Standards, or simply supported by a water pillow. The latter clamping device was used to differently distribute the load and to investigate about the influence of the water backing. The mechanics-based understanding of the fluid-structure interaction occurring during the impact, was devoted to understand the role of water-backing on the loading experienced by the panel, toward informing the interpretation of empirical observations and design of new experiments. Non destructive and destructive evaluations for damage investigations were carried out whereas the design and the production of a new, more simple and reliable Compression After Impact (CAI) apparatus, was described and adopted to avoid errors due to misalignment between the applied load and the specimen. CAI tests were then, performed to evaluate the residual compression strength. Analytical and semi empirical models were evaluated and validated to predict the influence of the geometric parameters on the impact behaviour of the laminates. The final aim was to predict the impact energy, delamination and residual strength, in the different test conditions.

      PubDate: 2017-07-02T12:58:19Z
       
  • Free vibration, wave power transmission and reflection in multi-cracked
           nanorods
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Arian Bahrami
      In this paper, the wave propagation method and the differential constitutive law consequent (not equivalent) to the Eringen strain-driven integral nonlocal elasticity model are utilized to analyze the free vibration, wave power transmission and reflection in multi-cracked nanorods. This aim is pursued by deriving the propagation, reflection and transmission matrices and comparing the natural frequencies obtained by these matrices with the available results in the literature. Then, the nonlocal, crack-severity, and crack location effects on the natural frequencies are presented for two combinations of the boundary conditions. Finally, the paper presents the effects that the reflected and transmitted power of a wave incident on a crack location receive from the nonlocal and crack-severity parameters. The results obtained via the reflection and transmission matrices will provide valuable insights into the subject of wave power reflection and transmission analysis in nanoscale structures for the future. The computer coding of the proposed method is much easier than the classical vibration analysis methods which makes it more appropriate in implementation.

      PubDate: 2017-07-02T12:58:19Z
       
  • Low-velocity impact response of E-glass reinforced thermoset and
           thermoplastic based sandwich composites
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Akar Dogan, Volkan Arikan
      This paper presents an experimental investigation on impact response of sandwich composite panels with thermoplastic and thermoset face-sheet. E-glass reinforced epoxy (thermoset) and polypropylene (thermoplastic) have been used to produce polymer composite face-sheets. PVC foam was used as a core material. Several low velocity impact tests were performed under various impact energies. Besides to the individual impact behavior of the thermoset and thermoplastic sandwich composites, the impact response of sandwich composites having hybrid sequences was also investigated. Along with images of damaged samples, variations of the impact characteristics such as absorbed energy, maximum contact force and maximum deflection of the samples are provided. Most particularly this study showed that sandwich composites must have the harmony between core and the face sheet material. The deformation required for core densification must be able to compensate by the face sheet material.

      PubDate: 2017-07-02T12:58:19Z
       
  • Experimental evaluation of the effect of partial saturation of
           construction moisture on CFRP-concrete debonding
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): M. Cuomo, R. Caponetto, A. Lo Presti, E. Ardizzone
      The mechanical strength of FRP reinforcements for concrete elements is greatly affected by the presence of water in the concrete. A great number of investigations has concerned the effects of moisture cycles in various conditions, simulating environmental degradation. In the paper are reported the results of an experimental investigations on the strength of FRP reinforcements installed on partially saturated concrete samples. Pull-off tests and Double Shear Tests were performed at three degrees of partial saturation. The resistance of the reinforcement at pull-off (which is a test used for assessing the conformity of existing reinforcements) was found to degrade by a larger amount than the resistance at shear. The failure mode was found to shift from fibre breakage to partial delamination in which part of the detachment occurred at the interface.

      PubDate: 2017-07-02T12:58:19Z
       
  • Mechanical characterization of textile reinforced inorganic-matrix
           composites
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): T. D'Antino, Catherine Papanicolaou
      This paper presents the results of the mechanical characterization of composite materials comprising high strength textiles embedded in inorganic matrices. These materials are commonly termed Textile Reinforced Mortars (TRM) or, when comprising cementitious matrices, Fabric-Reinforced Cementitious Matrix (FRCM – despite the fact that this term is often extended to composites with cement-free matrices). Different types of fibers were employed, namely carbon, glass, and basalt, as well as steel cords, which were embedded in lime- or cement-based matrices. Results of tensile tests on single fiber yarns and composite prismatic specimens with a rectangular cross-section are shown and discussed. The effect of fiber coating and stitch-bonded joints between warp and weft yarns on the tensile behavior observed is studied. The results obtained help to shed light on the different parameters that affect tensile testing of inorganic-matrix composites contributing to the appropriate mechanical characterization of these materials.

      PubDate: 2017-07-02T12:58:19Z
       
  • Mechanical and impact characterization of hybrid composite laminates with
           carbon, basalt and flax fibres
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): E. Nisini, C. Santulli, A. Liverani
      Ternary hybrids including carbon, basalt and flax fibres in an epoxy matrix have been fabricated by hand lay-up, then consolidated by vacuum bagging using two different stacking sequences. Both configurations involved the use of carbon fibres on the outside, whilst basalt and flax fibres were disposed internally either in a sandwich or in an intercalated sequence. They were subjected to tensile, flexural and interlaminar shear strength test, then to falling weight impact with three different energies, 12.8, 25.6 and 38.4 J, studying damage morphology and impact hysteresis cycles. Intercalation of basalt with flax layers proved beneficial for flexural and interlaminar strength. As regards impact performance, the differences between the two laminates were quite limited: however, the presence of a compact core of flax fibre laminate or else its intercalation with basalt fibre layers had a predominant effect on impact damage features, with intercalation increasing their complexity.

      PubDate: 2017-07-02T12:58:19Z
       
  • Round Robin Test on tensile and bond behaviour of Steel Reinforced Grout
           systems
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Stefano De Santis, Francesca Ceroni, Gianmarco de Felice, Mario Fagone, Bahman Ghiassi, Arkadiusz Kwiecień, Gian Piero Lignola, Mattia Morganti, Mattia Santandrea, Maria Rosa Valluzzi, Alberto Viskovic
      Mortar-based reinforcements are an innovative solution for retrofitting existing structures that combine effectiveness, compatibility, and sustainability. Despite the recent spreading of field applications, there is still insufficient knowledge on their fundamental mechanical properties, and a regulatory gap for experimental procedures and design criteria. A Round Robin Test initiative was organized by the Rilem TC 250-CSM (Composites for the Sustainable strengthening of Masonry) to investigate the tensile and bond behaviour of mortar-based composites with basalt, carbon, glass, polyparaphenylene benzobisoxazole (PBO), aramid and steel textiles. This paper presents the tests carried out on Steel Reinforced Grout (SRG) systems, comprising three textile and four mortar types, supplied by three producers. Ten laboratories from Italy, Poland and Portugal were involved for a total of 150 tests, including direct tensile tests on textiles and composites, and single-lap bond tests on masonry substrate. The influence of the layout of the textile, the mechanical properties of the mortar matrix, the manufacturing and curing conditions, as well as the testing setup and instrumentation, is discussed to contribute to the optimization of the reinforcement systems and to the development of recommendations for laboratory testing. Finally, results are combined to derive engineering parameters for qualification and design purposes.

      PubDate: 2017-07-02T12:58:19Z
       
  • Test methods for Textile Reinforced Mortar systems
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Stefano De Santis, Francesca Giulia Carozzi, Gianmarco de Felice, Carlo Poggi
      Textile Reinforced Mortar (TRM) composites, also named Fabric Reinforced Cementitious Matrix (FRCM), comprise high strength textiles embedded into inorganic matrices, and have been recently developed for the repair and rehabilitation of structures. Their effectiveness and compatibility with the substrate fostered the industrial development of a wide number of strengthening systems, which have been applied to masonry and reinforced concrete structures. Nevertheless, an improved knowledge still needs to be gained on their mechanical properties (tensile and bond behaviour) and on the effect they have on the structural performance of reinforced members. Furthermore, except for the US, no standards are available for testing, qualification and design. In this paper, the main features of the tensile and bond behaviour of TRM composites are described. Recommendations for performing direct tensile tests and shear bond tests are proposed, based on the outcomes of a Round Robin Test organized by the Rilem TC 250-CSM (Composites for the Sustainable strengthening of Masonry) and Assocompositi (Italian Industry Association for Composite Materials), carried out on 26 TRM systems (made of basalt, carbon, steel, glass, PBO and aramid textiles, with cement, lime or geopolymer mortar matrices), and involving 19 European research institutions and 11 industrial partners.

      PubDate: 2017-07-02T12:58:19Z
       
  • Seismic retrofitting of RC walls externally strengthened by flax–FRP
           strips
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): G. Di Luccio, L. Michel, E. Ferrier, E. Martinelli
      Several studies available in the literature have demonstrated that natural fibres can be employed in externally bonded (EB) fibre-reinforced polymer (FRP) strips used to strengthen existing reinforced concrete (RC) members. The study aims to demonstrate the feasibility of retrofitting RC walls using flax–FRP (FFRP). The study consists of an experimental campaign and analytical evaluations, the latter aimed at determining the evolution of relevant damage indices during cyclic loading processes. The behaviour observed in the tests of RC walls strengthened by FFRP is compared with that of both a reference wall and that of similar specimens strengthened with more conventional composite materials (i.e., carbon-FRP or CFRP). The test results show that FFRP has the potential to be used for seismic retrofitting as a viable alternative to more common FRP materials and other traditional techniques. Indeed, RC wall specimens strengthened with FFRP demonstrated strength increases of up to 150% and ductility gains equal to about 30%. Moreover, the tests show that walls strengthened by FFRP generally dissipate more energy than those strengthened with CFRP: this is an important property for the seismic strengthening and retrofitting of existing RC structures.

      PubDate: 2017-07-02T12:58:19Z
       
  • Bond between TRM versus FRP composites and concrete at high temperatures
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Saad M. Raoof, Dionysios A. Bournas
      The use of fibre reinforced polymers (FRP) as a means of external reinforcement for strengthening the existing reinforced concrete (RC) structures nowadays is the most common technique. However, the use of epoxy resins limits the effectiveness of FRP technique, and therefore, unless protective (thermal insulation) systems are provided, the bond capacity at the FRP-concrete interface will be extremely low above the glass transition temperature (T g ). To address problems associated with epoxies and to provide cost-effectiveness and durability of the strengthening intervention, a new composite cement- based material, namely textile-reinforced mortar (TRM) has been developed the last decade. This paper for the first time examines the bond performance between the TRM and concrete interfaces at high temperatures and, also compares for the first time the bond of both FRP and TRM systems to concrete at ambient and high temperatures. The key parameters investigated include: (a) the matrix used to impregnate the fibres, namely resin or mortar, resulting in two strengthening systems (TRM or FRP), (b) the level of high temperature to which the specimens are exposed (20, 50, 75, 100, and 150 °C) for FRP-reinforced specimens, and (20, 50, 75, 100, 150, 200, 300, 400, and 500 °C) for TRM-strengthened specimens, (c) the number of FRP/TRM layers (3 and 4), and (d) the loading conditions (steady state and transient conditions). A total of 68 specimens (56 specimens tested in steady state condition, and 12 specimens tested in transient condition) were constructed, strengthened and tested under double- lap direct shear. The result showed that overall TRM exhibited excellent performance at high temperature. In steady state tests, TRM specimens maintained an average of 85% of their ambient bond strength up to 400 °C, whereas the corresponding value for FRP specimens was only 17% at 150 °C. In transient test condition, TRM also outperformed over FRP in terms of both the time they maintained the applied load and the temperature reached before failure.

      PubDate: 2017-07-02T12:58:19Z
       
  • A new approach for nonlinear buckling analysis of imperfect functionally
           graded carbon nanotube-reinforced composite plates
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Pham Toan Thang, Tan-Tien Nguyen, Jaehong Lee
      This paper presents an analytical approach to analyze the nonlinear static buckling of imperfect functionally graded carbon nano-reinforced composite (FG-CNTRC) plates subjected to axial compression. The material properties of the FG-CNTRC are assumed to be graded through the thickness direction according to several linear distributions of the volume fraction of carbon nanotubes. The theoretical formulations are based on the classical plate theory (Kirchhoff plate) with von Karman-type of nonlinearity and the initial geometrical imperfection. The approximate solution is developed for simply supported and freely movable boundary conditions. By applying the traditional Galerkin method and the Airy stress function, the results for the critical load are obtained in closed-form solutions, which are convenient to be used in engineering design. Some illustrative examples are also presented in details to investigate the effects of the imperfection, carbon nanotubes, and geometrical parameters on the nonlinear static behavior the plates.

      PubDate: 2017-07-02T12:58:19Z
       
  • Experimental analysis on tensile and bond properties of PBO and aramid
           fabric reinforced cementitious matrix for strengthening masonry structures
           
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Carmelo Caggegi, Francesca Giulia Carozzi, Stefano De Santis, Francesco Fabbrocino, Francesco Focacci, Łukasz Hojdys, Emma Lanoye, Luigia Zuccarino
      The use of Fabric Reinforced Cementitious Matrix (FRCM) composites appears as a compatible and effective technique to strengthen masonry structures. The use of FRCM composites in place of FRP (fiber reinforced polymer) composites provides noticeable advantages in terms of fire and heat resistance and vapor permeability. These characteristics are of primary importance in the field of the strengthening historical buildings and monuments. This justifies the attention of the scientific community to the mechanical behavior of the FRCM materials with the aim to define exhaustive strengthening design guidelines. The experimental research presented in this paper involves direct tensile tests and single lap shear tests. It was carried out in the framework of the Technical Committee Rilem TC 250 CSM (Composites for the Sustainable Strengthening of Masonry). Specifically, this paper concerns FRCM systems comprising PBO (polyparaphenylene benzobisoxazole) or Aramid textiles.

      PubDate: 2017-07-02T12:58:19Z
       
  • Glass fabric reinforced cementitious matrix: Tensile properties and bond
           performance on masonry substrate
    • Abstract: Publication date: 15 October 2017
      Source:Composites Part B: Engineering, Volume 127
      Author(s): Marianovella Leone, Maria Antonietta Aiello, Alberto Balsamo, Francesca Giulia Carozzi, Francesca Ceroni, Marco Corradi, Matija Gams, Enrico Garbin, Natalino Gattesco, Piotr Krajewski, Claudio Mazzotti, Daniel Oliveira, Catherine Papanicolaou, Giovanna Ranocchiai, Francesca Roscini, Dorothea Saenger
      Fibre-reinforced composite materials have gained an increasing success, mostly for strengthening, retrofitting, and repairing existing structures. However some problems may arise with the use of traditional FRP (Fiber Reinforced Polymer), particularly when the compatibility with the substrate and the reversibility of the intervention are required, as in case of cultural heritage buildings, or specific exposition conditions may compromise the long term effectiveness of the reinforcement, as in presence of high temperature and humidity. Starting from these considerations new composite materials are emerging as a more effective solution in certain fields of application and under specific service conditions; in this context, mortar-based composite systems, consisting of one or more layers of uni- or bi-directional fibre nets embedded in cement/lime-based matrix layers, can be used as reinforcement of both concrete and masonry structures. However, the research work dealing with these emerging materials and their performances when used as a strengthening system for existing structures is still limited. Both experimental and theoretical investigations are needed in order to deliver reliable design methodologies. In this work, a Round Robin Test aimed to the characterization of both bond with the existing substrate and tensile performance of glass fabric (in the form of grids) coupled with inorganic mortar matrices is presented. The investigation was conducted at fifteen laboratories involved in the RILEM Technical Committee 250-CSM (Composites for the Sustainable Strengthening of Masonry). With the aim of studying the bond behaviour between Fabric Reinforced Cementitious Matrix (FRCM) composites and masonry substrate, single and double lap shear tests were carried out on brick-masonry prisms. Results provide useful informations about the mechanical properties, the bond capacity and the failure mechanisms of different commercially available glass FRCM systems. Finally, critical aspects are underlined to address the progress of the research work.

      PubDate: 2017-07-02T12:58:19Z
       
  • A posteriori stress and strain recovery procedure for the static analysis
           of laminated shells resting on nonlinear elastic foundation
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Francesco Tornabene, Nicholas Fantuzzi, Michele Bacciocchi, J.N. Reddy
      The numerical analysis of laminated composite plates and shells resting on nonlinear elastic foundation is the main topic of the paper. The generalized differential quadrature (GDQ) technique and the Newton-Raphson iteration are employed to obtain the solution of the static problems under consideration. The nonlinear elastic foundation is modeled using the Winkler-Pasternak model embedded with quadratic and cubic nonlinearities in order to a have a more complete description of the interaction. The structural behavior is modeled by means of higher-order displacement fields developed in the framework of a unified formulation. Several lamination schemes are studied. The class of sandwich structures with an inner soft-core is also taken into account with the help of the Murakami’s function, which correctly captures the so-called zig-zag effect. The presented approach can deal with doubly-curved surfaces characterized by two radii of curvature that can vary in each point of the reference domain, whereas most of the examples available in the literature considers only shells with constant curvature, such as spherical and cylindrical shells. Solutions are presented in terms of through-the-thickness variations of strains, stresses, and displacements. For these purposes, a posteriori recovery procedure based on the GDQ method is introduced. The accuracy and effectiveness of the proposed approach are proven by means of the comparison with the numerical results obtained by a three-dimensional finite element model.

      PubDate: 2017-07-02T12:58:19Z
       
  • Effect of the fringing electric field on the apparent electric
           permittivity of cement-based materials
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Yulin Wang, D.D.L. Chung
      The fringing electric field increases the apparent relative permittivity of cement when the electrodes do not cover the entire specimen area. The apparent permittivity increases with increasing thickness, decreases with increasing area, and is much higher when the permittivity is obtained from the slope (P) of 1/C versus thickness than the slope (Q) of C versus area (C = measured capacitance). Using P, the value (2 kHz) for various areas is 830–1760 and 810–1750 for plain and silica-fume cements, respectively. Using Q, the value for various thicknesses is only 150–375 and 144–354 for plain and silica-fume cements, respectively. When the electrodes cover the entire area, the fringing field effect is weaker, with lower relative permittivity 24–38 and 23–36 for plain and silica-fume cements, respectively.

      PubDate: 2017-07-02T12:58:19Z
       
  • Carbon nanotube-grafted carbon fiber polymer composites: Damage
           characterization on the micro-scale
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Luman Zhang, Niels De Greef, Gerhard Kalinka, Bart Van Bilzen, Jean-Pierre Locquet, Ignaas Verpoest, Jin Won Seo
      Multiwall carbon nanotubes (CNTs) – carbon fibers (CFs) hybrid materials were produced by directly growing CNTs on CFs by means of chemical vapor deposition. For the latter, the oxidative dehydrogenation reaction of C2H2 and CO2 was applied, which allows growing CNTs without damaging the CF surface. Uni-directional nano-engineered carbon fiber reinforced composites (nFRCs) were fabricated by impregnating these hybrid materials with epoxy. The nFRCs subjected to single fiber push-out tests revealed a decrease of the interfacial shear strength (IFSS) of about 36% compared to the carbon fiber composites without CNTs. By means of transverse three-point bending tests performed on pre-notched composite beams inside a scanning electron microscope, the fracturing behavior parallel to the fibers was studied in-situ. The nFRCs showed significantly reduced fiber/matrix debonding while CNTs pull-out, CNTs bridging as well as matrix failure occurred. These results demonstrate that the presence of CNTs in nFRCs affects the stress distribution and consequently the damage initiation as well as the damage propagation. The presence of CNTs suppresses the stress concentration at the fiber/matrix interface and reduces the debonding of CFs from the matrix. However, our results indicate that the stress concentration shifts towards the CNTs' ends/matrix interface and causes promoted matrix failure leading to lower IFSS.

      PubDate: 2017-07-02T12:58:19Z
       
  • Durability of CFRP/steel joints under cyclic wet-dry and freeze-thaw
           conditions
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Mohsen Heshmati, Reza Haghani, Mohammad Al-Emrani
      Strengthening of steel structures with adhesively bonded carbon fibre reinforced polymer (CFRP) materials have become increasingly popular in the last decade. However, uncertainties regarding the durability and long-term performance of CFRP/steel joints is a major obstacle for their growing application. Previous research indicates the deleterious effects of moisture and thermal cycles on the mechanical performance of these joints. To the authors' knowledge, the combined effects of moisture and thermal cycles have been scarcely investigated. This paper presents the results of extensive experimental investigations at material- and joint-level subjected to various cyclic environmental scenarios. Special consideration is given to the role of moisture, i.e. distilled- or salt-water, when combined with freeze-thaw cycles. Moreover, the possibility of providing a predictive modelling platform for residual strength prediction of environmentally aged joints using sequentially coupled moisture diffusion-fracture analysis is explored. The results show 11% and 47% strength reductions for the CFRP/steel joints after a complete wet-dry cycle in distilled- and salt-water, respectively, which are significantly larger than those observed after only the wet exposure. In addition, 125 and 250 freeze-thaw cycles were found to have no unfavourable effects on the strength of dry or preconditioned joints.

      PubDate: 2017-07-02T12:58:19Z
       
  • Lab and field studies into effectiveness of flat steel plate – rubber
           pad systems as tyre substitutes for local loading of cellular GFRP bridge
           decking
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): W.M. Sebastian, M. Ralph, M. Poulton, J. Goacher
      The current preferred approach to assessing the local tyre load fatigue performance of cellular FRP bridge decks entails cyclic loading of the decks using flat, rectangular steel plates faced with rubber pads. Significantly, the plate-pad details are taken from standards developed for concrete and steel decks. For this approach to succeed with FRP decking, the local load distribution on the deck from the plate-pad system must mimic that from a tyre. To that end, this paper presents contact pressure distributions (CPDs, recorded using an electronic mat pressure sensor) exerted on a FRP deck at different loads by plate-pad systems in lab tests and by lorry tyres at different inflation pressures in field tests. The field data reveal that as the tyre load increased, the tyre-deck contact patch evolved from a circle to an ellipse and then to a square, causing the contact load profile to morph from a triangle to a trapezium. This changing geometry of the tyre-deck CPD led to distinctly nonlinear variations, with the tyre load, of the local surface strains recorded from the deck. Empirical definitions of these tyre-deck load profiles are proposed, based partly on use of the field data in FE analysis. Across the spectrum of realistic tyre loads and inflation pressures investigated, the plate-pad systems (particularly with rubber pads) induced far less onerous CPDs on and local strain responses from the deck than did the tyres. In closing, the paper identifies the need to also quantify fibre waviness, in a move towards fatigue performance prediction for FRP decks.

      PubDate: 2017-07-02T12:58:19Z
       
  • Experimental and numerical investigations on the flexural performance of
           geopolymers reinforced with short hybrid polymeric fibres
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): M. Kheradmand, M. Mastali, Z. Abdollahnejad, F. Pacheco-Torgal
      Geopolymers have much higher drying shrinkage than Portland cement based composites Shrinkage performance is an important property for reinforced concrete composites just because a high shrinkage performance is associated to cracking tendency that leads to future durability problems. This paper provides results experimental and numerical investigations of fly ash based geopolymeric mortars reinforced with short hybrid polymeric fibres (SHPF). The results show that SHPF improved the flexural performance, while reducing the compressive strength and flexural stiffness of geopolymeric mortars. The addition of 0.8% SHPF increased about two times the fracture energy and about 50% the tensile strength. The adopted constitutive model well-captured the flexural performance of the tested beams.

      PubDate: 2017-06-20T19:58:22Z
       
  • Process analysis for structural optimisation of thermoplastic composite
           component using the building block approach
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): N. Amirth Jayasree, A.G. Airale, A. Ferraris, A. Messana, L. Sisca, M. Carello
      The paper aim is to establish and optimise the prediction model of a thermoplastic fibre reinforced component designed and manufactured through an integrated injection moulding process (Hybrid Moulding). This is done by the Finite Element Analysis (FEA) and then the process simulations, considering the composite material as an elastic anisotropic woven fabric to study the deformations undergone during the manufacturing process. The proposed methodology for creating the predictive model is fairly accurate, and it is a novel method which can be easily integrated and adapted into a components initial design phase. This optimisation technique can replace the expensive and traditional trial and error procedures during the design and prototyping phase, and it significantly decreases the time to build the final component. The final scope of the research is to simplify the product development phase of general lightweight automotive thermoplastic components by creating an innovative methodology for predictive modelling.

      PubDate: 2017-06-20T19:58:22Z
       
  • Experimental study into compression after impact strength of laminates
           with conventional and nonconventional ply orientations
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Yi Liv, G. Guillamet, J. Costa, E.V. González, L. Marín, J.A. Mayugo
      The quest for impact damage tolerant laminates by tailoring stacking sequences has led to nonconventional laminates whose ply sequences are not limited to 0, ±45 and 90°. Departing from the hypothesis that compression after impact (CAI) strength is impaired by the presence of delaminations, a ply sequence was defined by selecting the mismatch angles between plies so as to maintain a central sublaminate with no, or small, delaminations. An experimental test campaign was devoted to validate this hypothesis. To that purpose, baseline and blocked-ply laminates were included in the study. Specimens were tested under low velocity impact followed by compression according to ASTM standards. Delaminations were identified with Ultrasonic C-Scan. The results show delamination locations being successfully predetermined by controlling the mismatch angle, as well as the ensuing improvement in compressive strength retention after impact.

      PubDate: 2017-06-20T19:58:22Z
       
  • Research on strength of nanocomposite adhesively bonded composite joints
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Iclal Avinc Akpinar, Kürşat Gültekin, Salih Akpinar, Hamit Akbulut, Adnan Ozel
      Due to their great advantages, adhesively bonded joints are frequently used in many areas like automotive, marine, space and aerospace industries. Especially findings from nanoscience and nanotechnology, which have progressed significantly in recent years, influence adhesives sciences significantly as well as other disciplines. In the present study, nanoparticles were added to the adhesive to increase the damage load of adhesively bonded single lap composite joints and tensile and bending moment damage loads of these joints were experimentally investigated. In the study, carbon fiber fabric reinforced composites (0/90°) with Plain Weave were used as the adherend; rigid, tough and flexible adhesive types were used as the adhesive and 1 wt% Graphene-COOH, Carbon Nanotube-COOH and Fullerene C60 were used as the nanoparticles. As a result, based on the AA2024-T3 aluminum alloy used in a study conducted by Akpinar et al. [1], the use of carbon fiber fabric reinforced composites as the adherend considerably increases the damage load of the joint, depending on the adhesive type. Moreover, when failure loads obtained from experiments were examined, the addition of nanoparticles to the adhesive was shown to increase the tensile and four-point bending damage load of joint, depending on the adhesive and nanoparticle type.

      PubDate: 2017-06-20T19:58:22Z
       
  • A novel sandwich footbridge - Practical application of laminated
           composites in bridge design and in situ measurements of static response
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Jacek Chróścielewski, Mikołaj Miśkiewicz, Łukasz Pyrzowski, Bartosz Sobczyk, Krzysztof Wilde
      A novel sandwich composite footbridge is presented in the paper, as an example of practical application of laminated composites in civil engineering. The in situ static load tests of the footbridge before its acceptation for exploitation are shown and discussed. The results are compared with the corresponding ones from a numerical equivalent single layer model of the sandwich structure created within the framework of finite element method. The numerical solutions, are slightly higher than the measured in situ ones. Hence, it is concluded that the chosen method of structural analysis is efficient enough to recreate static behavior of the bridge and thus it is accepted for application in civil engineering.

      PubDate: 2017-06-20T19:58:22Z
       
  • Modelling the damage evolution in notched omega stiffened composite panels
           under compression
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): A. Riccio, A. Sellitto, S. Saputo, A. Russo, M. Zarrelli, V. Lopresto
      In this paper, the compressive behaviour of an omega stiffened composite panel with a large notch damage has been investigated. The influence of intra-laminar and inter-laminar damage onset and evolution on the compressive behaviour of a stiffened panel, characterised by a cut-out located in the middle bay and oriented at 45° with respect to the load direction, has been studied. A numerical model, taking into account delamination and fibre-matrix damage evolution, respectively, by means of cohesive elements and Hashin's failure criteria together with material degradation rules, has been adopted. By comparing the performed numerical analyses, taking into account intra-laminar and inter-laminar damages, the effects of the interaction between delaminations and fibre-matrix damage in the large notch area on the global compressive behaviour of the omega stiffened composite panel have been assessed and critically discussed.

      PubDate: 2017-06-16T19:43:51Z
       
  • An investigation into the effects of fabric reinforcements in the bonding
           surface on failure response and transverse impact behavior of adhesively
           bonded dissimilar joints
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Okan Ozdemir, Nahit Oztoprak
      The purpose of the current study is to evaluate the failure response and transverse impact behavior of adhesively bonded dissimilar single-lap composite joints fabricated by using fiber-reinforced polymer. The adherend materials utilized for the experimental tests were AA6082-T6 and glass fiber reinforced polymer (GFRP) in the form of thin sheets. The adhesive used was a warm to hot curing epoxy system (Araldite LY 1564 SP/Aradur 3487 BD) manufactured by Huntsman. In this study, some modifications were provided to enhance the failure response of single-lap composite joints. These modifications comprise the addition of different type and number of fabric reinforcements in the bonding surface. Based upon the test results, an increase of 33.6% in the failure load at room temperature is obtained for the joint fabricated by the addition of double-layer glass fabric reinforcement in the bonding surface. However, the failure load of all types of joint modifications decreases with the increasing tensile test temperature from room temperature to 75 °C. Similarly, tensile tests of the same specimen also resulted in double failure displacement by comparison with the adhesively bonded joint through only epoxy without any fabric reinforcement. The effect of low velocity impact on the failure response of the joints at the impact energy level of 2.5 J is also evaluated. From the tensile tests subsequent to impact treatment, it was found that the transverse impact significantly reduced the failure load of all types of joint modifications. However, the adopted modifications provided tensile failure loads over 1875 N and 1270 N for the joint fabricated by using double-layer carbon and glass fabric reinforcements, respectively.

      PubDate: 2017-06-16T19:43:51Z
       
  • Novel Chitosan-poly(vinyl alcohol)/graphene oxide biocomposites 3D porous
           scaffolds
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Andreea Madalina Pandele, Mariana Ionita, Livia Crica, Eugeniu Vasile, Horia Iovu
      New porous Chitosan-Poly(vinyl alcohol)/graphene oxide (CHT-PVA/GO) biocomposites scaffolds were obtained by a freeze drying method. The structural and morphology properties of the scaffolds were investigated. Fourier transmission infrared (FTIR) spectra confirmed the presence of GO into the biopolymer matrices. Scanning Electron Microscopy (SEM) images show a highly interconnected porosity for the composites with GO incorporated within the polymer matrices. Further, the water uptake capacity and the enzyme degradation behavior were conducted. The biocomposite ability to form hydroxyapatite (HA) crystals and therefore bone regeneration potential was studied. SEM shows that all the samples are covered with a mineral phase made of micro globule needle type. The presence of HA crystals on the surface was proved by X-ray Diffraction (XRD) where a large number of the characteristic peaks of HA were observed, the average size of individual crystallite being dependent on GO amount.

      PubDate: 2017-06-16T19:43:51Z
       
  • Investigating thermal properties of using nano-tubular ZnO powder in
           paraffin as phase change material composite for thermal energy storage
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Nurten Şahan, Halime Paksoy
      The thermal energy storage (TES) in phase change materials (PCMs) plays an important role in energy management systems. Paraffin has found wide range of applications as a PCM due to its unique thermal and physical properties. In this study, nano zinc oxide in tubular shape and powder form is synthesized for the first time in literature. The nano tubular-zinc oxide is used as an additive with 10%wt composition to paraffin to prepare a nanocomposite. The variations in thermo physical properties of paraffin in composite form were subjected to investigate by experimentally.

      PubDate: 2017-06-16T19:43:51Z
       
  • Water transport kinetics and thickness swelling behavior of natural
           fiber-reinforced HDPE/CNT nanocomposites
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Behzad Kord, Mehdi Roohani
      This study mainly focused on investigating the effect of carbon nanotubes (CNTs) on the long-term hygroscopic behavior of composites based on old corrugated container (OCC) and high density polyethylene (HDPE). Composite profiles were made by melt compounding and then injection molding. For CNT as a reinforcing agent, different loading levels of 0, 1, 3 and 5 phc was used. The amount of HDPE and coupling agent was fixed at 50 wt% and 2 phc for all formulations, respectively. The governing kinetic behavior of water transport in the studied composites was examined by immersing them in water at room temperature for several weeks, and water diffusion coefficients were also calculated by evaluating the water absorption isotherms. In addition, a predictive model for determining the thickness swelling rate of the samples was developed by Shi and Gardner model. Results indicated that the composites filled with CNT had considerably lower water absorption compared with those samples without ones. The absorption processes for all families of composites were found to exhibit Fickian diffusion behavior. It was found that that equilibrium thickness swelling and also shorter equilibrium time (the time to reach the equilibrium thickness swelling) decreased with increase of CNT loading. Furthermore, the swelling model provided a good predictor of the hygroscopic thickness swelling process of HDPE/OCC/CNT hybrid composites. Also, a good linear relationship was fit between swelling rate parameter (K SR ) and CNT contents. The minimum K SR values were observed in composites made of 5 phc CNT.

      PubDate: 2017-06-16T19:43:51Z
       
  • Epoxy/glass fibres composites for civil applications: Comparison between
           thermal and microwave crosslinking routes
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): F. Colangelo, P. Russo, F. Cimino, R. Cioffi, I. Farina, F. Fraternali, L. Feo
      Fiber-reinforced polymers (FRPs) have gained a growing interest for civil applications mainly for their lightness, corrosion resistance and high specific mechanical properties especially in terms of stiffness and strength. In this work, epoxy/glass fibres composite formulations, prepared by thermal and microwave assisted curing routes, are systematically characterized by thermal and mechanical tests. In particular the thermal curing is performed at room temperature and at 100 °C while the microwave conditions are set at 1500 W for 10 min. Calorimetric measurements demonstrate that these processing conditions allow to prepare samples with comparable crosslinking degree. The time and cost-saving microwave approach gives rise to cured FRPs with higher flexural stiffness but, expectedly, characterized by a network with a structure more inhomogeneous with respect to thermal crosslinked ones. Pull-out strength determination of all investigated epoxy composite systems joined to three different supports: a conventional concrete (CC), an artificial aggregate concrete (AAC) and a geopolymer (G), are performed to highlight their potential use for civil engineering applications. The experimental findings further support the use of microwave cured FRP samples especially with respect to the CC support.

      PubDate: 2017-06-16T19:43:51Z
       
  • A semi-analytical model for sound propagation in sintered fiber metals
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Shuwei Ren, Qingbo Ao, Han Meng, Fengxian Xin, Lixi Huang, Chuanzeng Zhang, Tian Jian Lu
      A semi-analytical model based on three-dimensional (3-D) periodical unit cells (PUCs) is developed to predict the sound absorption performance of sintered fiber metals as a function of porosity and fiber diameter. The PUC is developed from the most simplistic one (PUC1) to the comparatively complex one (PUC3) by taking into account the shifting of fiber position and the non-uniformity of fiber distribution. Upon numerically solving both the static Stokes (aiming at viscous flow) and diffusion-controlled reaction (aiming at inertial flow) equations defined inside the PUC, the transport parameters in the commonly used JCA (Johnson-Champoux-Allard) model for porous acoustic materials are obtained. Upon introducing the Kozeny number and pore shape factor, key transport parameters are determined as functions of fiber diameter and porosity using the proposed semi-analytical model. The theoretically predicted sound absorption coefficients are compared with experimental measurements of sintered fiber metal samples, with good agreement achieved. The validated model is then used to systematically analyze the influence of fiber diameter and porosity on sound absorption. The model reveals the physical mechanisms underlying viscous and thermal dissipation of sound energy due to fluid-structure interaction in sintered fiber metals.

      PubDate: 2017-06-12T05:57:22Z
       
  • Uniqueness results for a boundary value problem in dipolar
           thermoelasticity to model composite materials
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): M. Marin, E.M. Craciun
      Composites with microstructure display nonlocal effects and can be effectively modeled through dipolar elasticity. A mixed initial boundary problem is addressed for dipolar thermoelasticity. The basic equations and conditions of the problem are set-up and uniqueness results are proven, which are obtained without introducing definiteness restrictions on the elastic coefficients and, also, without the usual condition imposed to the heat conductivity tensor of being positive definite. An additional result is finally obtained, namely, a reciprocal identity of the Betti's type which underlies another uniqueness result obtained again under weak restrictions.

      PubDate: 2017-06-12T05:57:22Z
       
  • Tensile failure analysis and residual strength prediction of CFRP
           laminates with open hole
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): Mengli Xiao, Zhang Yongbo, Wang Zhihua, Fu Huimin
      Failure patterns and damage mechanism of CCF300/QY8911 and T300/QY8911 composite laminates with open hole had been investigated experimentally and numerically. CCF300/QY8911 composite laminates with a weak interfacial strength produced massive delaminations and splitting bonds which relieved the stress concentration, thus having a higher strength. T300/QY8911 composite laminates with a higher interfacial strength presented to be brittle fracture with much less delaminations. The failure process, delamination propagation and residual strengths had been simulated and predicted by 2D and 3D Finite element (FE) modeling techniques. The delamination that allowed damage to join up and propagate through the thickness of the laminate had been identified as the critical character for residual strength prediction, which was compared in the simulation detailed. In the 2D modeling it made a good strength prediction for T300/QY8911 composite, but not for CCF300/QY8911 composite which contained massive delaminations and not been considered in this model. However, the 3D model proposed by our study could well simulate the delamination progressive propagation process, and predict the residual strength accurately. Furthermore, the effect of delamination defect around the hole that was unavoidable during hole drilling process was also investigated by the 3D modeling.

      PubDate: 2017-06-12T05:57:22Z
       
  • Static and vibration analysis of sandwich cylindrical shell with
           functionally graded core and viscoelastic interface using DQM
    • Abstract: Publication date: 1 October 2017
      Source:Composites Part B: Engineering, Volume 126
      Author(s): A. Aliyari Parand, A. Alibeigloo
      In the present paper, elasticity solution for static and free vibration analysis of sandwich cylindrical shell with functionally graded (FG) core and viscoelastic interface is carried out. Variation of Young's Module and material density of FGM core layer are assumed to obey power-law of radial coordinate with the Poisson's ratio holds to be constant. Imperfect interfaces are modeled according to the Kelvin-Voigt viscoelastic law. State space differential equations are derived using differential equations of motion as well as stress-displacement relations. For sandwich cylindrical shell with simply supported boundary conditions, these equations are solved analytically by using Fourier series expansion along the axial and circumferential direction. Whereas they are solved semi-analytically for the other cases of boundary conditions by using one dimensional differential quadrature method (DQM) along the axial coordinate. Time-dependent behavior is determined by solving first-order differential equation of sliding displacement at the viscoelastic interfaces. Numerical results are computed and compared with the reported results in literature to validate the present approach. In addition, effects of solid, elastic interfaces, different boundary conditions, time and mid radius to thickness ratio on the bending and vibration behavior of the sandwich shell are studied.

      PubDate: 2017-06-07T11:47:08Z
       
  • Anisotropy and holes in epoxy composite reinforced by carbon/glass and
           carbon/aramid hybrid fabrics: Experimental and analytical results
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): A.C.M.C. Batista, S.R.L. Tinô, R.S. Fontes, S.H.S. Nóbrega, E.M.F. Aquino
      This study is based on research into the effect of anisotropy and the presence of holes on mechanical properties and final fracture characteristics in uniaxial tensile testing of two laminates, one using a carbon/glass fiber hybrid fabric and the other a carbon/aramid fiber hybrid fabric in loading directions at 0°, 90° and ±45°. Both laminates were impregnated with epoxy vinyl ester thermosetting resin (Derakane Momentum™ 411-350). An analytical study assesses stress concentration using the Point Stress Criterion (PSC) and Average Stress Criterion (ASC). The results show the direct influence of anisotropy, holes and residual properties on all the parameters studied. With respect to failure theories, both PSC and ASC showed good agreement when the geometric K value was used.

      PubDate: 2017-06-02T12:58:22Z
       
  • Effects of bolt torque tightening on the strength and fatigue life of
           airframe FRP laminate bolted joints
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Ioannis K. Giannopoulos, Damian Doroni-Dawes, Kyriakos I. Kourousis, Mehdi Yasaee
      The experimental study presented herein, investigated the effects of bolt torque tightening on the strength and fatigue design of bolted AS7/8552 fibre reinforced polymer laminates. Damage initiation and final failure manifestation on the joints was investigated and presented using optical microscopy. Subsequent experimental result analysis explored the application domain of bolted joints within the airframe design sector, bound by the current airworthiness certification requirements and expected airframe design life. The reasons for the static strength of the joint laminates or the fatigue failure of the bolt being the main design drivers for the tested joints were highlighted. The study concluded with comments and suggestions on the application of bolt torque tightening in relation to the strength, fatigue life and damage tolerance characteristics of joints on similar fibre reinforced polymer laminate composite material systems.

      PubDate: 2017-06-02T12:58:22Z
       
  • An approach on capturing the influence of the stochasticity of fibre
           distributions for modelling the variability of cutting forces in composite
           materials
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Jiawei Mei, Oriol Gavalda Diaz, Dragos A. Axinte
      The paper presents a novel model to evaluate the variation of orthogonal cutting forces for randomly distributed unidirectional fibres when cutting composite structures. The distribution analysis of fibre locations is first introduced into this topic, and has been experimentally validated, resulting in a Gaussian distribution based random method to simulate the stochastic fibre locations within composites. The dedicated cutting force model divides the resultant forces into fibre and matrix cutting forces, and for the first time is able to predict the force variations corresponding to the stochastic fibre distributions. The orthogonal cutting of unidirectional fibre composite is classified into three cases based on the relation between the tool feed direction and the fibre orientation, all these cases are taken into account to validate the proposed model. The validation shows that both cutting forces and fibre locations follow the Gaussian distribution with a standard error lower than one percent, and the simulated fibre locations show a satisfactory agreement with the real composite internal structure during distribution analysis. Furthermore, the predicted cutting forces coincide with the experimental data, especially their variations evaluated by probability density function and cumulative distribution function demonstrate the high degree of consistency between them. This work also indicates the proposed modelling framework could be of high relevance to other relevant applications, such as energy consumption and tool wear estimation, where the understanding of the dynamic cutting forces is crucial.

      PubDate: 2017-06-02T12:58:22Z
       
  • The effect of manufacturing parameters on the surface roughness of glass
           fibre reinforced polymer moulds
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): M. Shah Mohammadi, M. Ghani, M. Komeili, B. Crawford, A.S. Milani
      The use of Glass Fibre Reinforced Polymer (GFRP) composite moulds has gained considerable attention in composites manufacturing, especially in open-mould processes; owing to several benefits including ease of processing, maintenance as well as low capital cost of tooling. Nevertheless, the surface of GFRP moulds is susceptible to degradation during the composite manufacturing processes which, if not properly maintained, can significantly increase the cost of repairs; and in severe cases, disposal of the mould may be required. In addition, poor surface quality of a mould can directly result in reduced surface finish of the manufactured part. This study, using a systemic design of experiments approach, investigates the effect of select manufacturing process parameters (de-moulding temperature, amount of release agent and environmental storage condition) on the ensuing surface roughness of typical GFRP moulds as used by industry. For this purpose, an open-mould process was simulated whereby a mould/part assembly consisting of top and bottom chopped fiber laminates with gel coat layers, and the release agent between them, was fabricated and subsequently the cured mould/part assembly was de-moulded under both tensile and shear modes. Specimens were tested at different factor combinations and the statistically significant parameters were identified, via analyzing the force values as well as surface roughness measurements on the moulds using White Light Interferometry. Finally, some practical guidelines were sought on the basis of observed individual and interactive effects of parameters.

      PubDate: 2017-06-02T12:58:22Z
       
  • Al-Mg-Si/SiC laminated composites: Fabrication, architectural
           characteristics, toughness, damage tolerance, fracture mechanisms
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Asal Hosseini Monazzah, Hesam Pouraliakbar, Reza Bagheri, Seyed Morteza Seyed Reihani
      Different architectures of layered laminates comprising two exterior layers of Al-Mg-Si/SiC metal matrix composite and an Al1050 ductile interlayer were fabricated by means of hot roll-bonding with applying different strains of εr = 39%, 51%, and 63%. For monolithics production, ceramic particulate reinforcement contents of 0, 5, 10, and 15 vol% were utilized. The aim of introducing ductile metal interlayer was to compensate the low toughness of composite layers and consequently enhancement of damage tolerance of bundled structures along with prevention of their catastrophic failure through activation of extrinsic toughening mechanism. Effects of architectural characteristics and fabrication routes on toughness and fracture behavior of materials were studied by mechanical examinations including three-point bending (3PB) and shear tests. Fracture surfaces of 3PB examination were studied by SEM while associated mechanisms and correlations with debonded area (delamination), deformability, and SiC content were disclosed and discussed. Different analyses by deriving σm were performed and the role of reinforcement content, lamination and εr were defined. Deformability of fabricated materials by identifying et, ei, and ep parameters were discussed. Based on results, et trend was obeyed ep rather than ei due to more ep contribution in materials' total ductility. Toughness change by accounting initiation and propagation values were surveyed considering the combined effects of σm, elongation, and stress-bearing capacity. Eventually, it was inferred that toughness was strongly controlled by elongation alteration. In addition, the contribution of propagation was more highlighted rather than initiation for laminates. Based on fracture surfaces, in monolithic samples, fracture morphology associated with SiC concentration. Fracture morphology of exterior composite layers had not been affected by εr in laminates; since interlayer fracture was strongly influenced by rolling. This was due to distinct involved failure mechanisms. Al1050 deformability was governed by delamination length as an indication of constraint level. Interfacial strength which acquired by shear test revealed that composite laminates had not been influenced by εr due to the weak bondings of layers beside presence of SiC particles; however, aluminum laminates showed enhanced shear strength.
      Graphical abstract image

      PubDate: 2017-06-02T12:58:22Z
       
  • Durability of RC slabs strengthened with prestressed CFRP laminate strips
           under different environmental and loading conditions
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Luís Correia, José Sena-Cruz, Julien Michels, Paulo França, Eduardo Pereira, Gonçalo Escusa
      Over the last decades, researchers have been studying fibre reinforced polymer (FRP) materials and their advantages in retrofitting of existing structures. The externally bonded reinforcement (EBR) technique is the most common practice in improving existing reinforced concrete (RC) structures with carbon FRP (CFRP) materials. In this regard, several additional advantages have been reported to the use of prestressed CFRP materials, mainly strips. However, the experience with RC strengthening using prestressed EBR-CFRP materials is still limited. Some concerns regarding the efficiency of the technique still exist, especially the durability and the long-term behaviour. This work aims at contributing to the knowledge on durability of RC slabs strengthened with prestressed CFRP laminate strips according the EBR technique. The durability was studied by exposing strengthened RC specimens to the following environments for approximately 8 months: (i) reference environment – specimens kept in a climatic chamber at 20 °C; (ii) water immersion in tank at 20 °C of temperature; (iii) water immersion in tank with 3.5% of dissolved chlorides at 20 °C of temperature; and (iv) wet/dry cycles in a tank with a water temperature of 20 °C. Additionally, half of the specimens were subjected to sustained loading at a load level of 1/3 of the ultimate load, with the occurrence of cracking. After the exposure period the slabs were monotonically tested up to failure by using a four-point bending test configuration. The results showed that the environmental conditions and the sustained loading, separately or combined, led in general to slight losses of performance and ductility. Although these losses were subtle, considering that the tests were carried out for 8 months, clear indications are given towards the importance of conducting similar tests for longer periods. The results obtained showed that the procedures implemented to assess the durability of the strengthening systems were sensitive to the most relevant deterioration mechanisms and their impact on the mechanical properties of the specimens. Therefore, these procedures may well contribute for the future establishment of standardized test programmes for the assessment of the durability of prestressed CFRP strengthening systems.

      PubDate: 2017-06-02T12:58:22Z
       
  • Structural analysis of failure behavior of laminated glass
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Giulio Castori, Emanuela Speranzini
      The use of laminated glass is increasing since it is able to guarantee robustness requirements so by improving the post-breaking characteristics of the glass. Due to the brittle nature of glass the reason for employing such composite materials are related to their ability to avoid cracks propagation, retain the glass fragments and present a post-cracking phase. Since the behavior of laminated glass depends on the constituent materials and especially on the type of interlayer, this research deals with the structural behavior of laminated glass plates made with different types of interlayer materials: PVB, SGP, EVA and XLAB. Twenty-four specimens were constructed with two annealed glass plies and transparent interlayer and were subjected to four point bending tests with the aim to study their structural behavior in both elastic and post-breaking phases. Laboratory outcomes highlight the enhanced initial-breakage strength of the XLAB plates, as well as the influence of the laminate type on the post-failure safety, since the use of thicker (double or triple ply) and/or stiffer (such as SGP and XLAB) interlayers seemed not to improve the residual load-carrying capacity. Finally, a 3-dimensional FE model is also presented for reproducing the structural behavior of the glass plates. The ability of the numerical model to reproduce experimental results for the load–deflection curves is validated promoting a deeper understanding and knowledge of the capabilities of the different types of interlayers in the context of the laminated glass design.

      PubDate: 2017-06-02T12:58:22Z
       
  • Quasi-static and dynamic tensile properties of basalt fibre reinforced
           polymer
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Wensu Chen, Hong Hao, Michael Jong, Jian Cui, Yanchao Shi, Li Chen, Thong M. Pham
      Basalt Fibre Reinforced Polymer (BFRP) has been becoming more and more popularly used in structural strengthening and rehabilitation due to its advantages of high strength to weight ratio, easy to install, and anti-corrosion. During the service life, BFRP strengthened structures might be subjected to dynamic loadings such as blast and impact loads. It is essential to understand the material mechanical properties, especially the dynamic material properties of BFRP for reliable predictions of the performances of BFRP strengthened structures subjected to dynamic loads. Very limited study on the static and dynamic tensile properties of BFRP material is available in the literature. In this study, quasi-static and dynamic tests of the unidirectional BFRP with a unit weight of 300 g/m2 were conducted to examine the material properties of tensile strength, modulus and failure strain at various strain rates. The strain rate sensitivity on the material properties of BFRP was analyzed and discussed. Empirical formulae for the strength, elastic modulus and failure strain of BFRP material were proposed to estimate the dynamic enhancement at different strain rates.

      PubDate: 2017-06-02T12:58:22Z
       
  • Experimental and numerical study of aluminum foam-cored sandwich tubes
           subjected to internal air blast
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): Minzu Liang, Fangyun Lu, Guodong Zhang, Xiangyu Li
      The blast response of aluminum foam-cored sandwich tubes that were subjected to internal air blast was investigated experimentally and numerically. Blast experiments were performed to capture the fundamental deformation, the maximum deflection of the inner face-sheet (MDIF), and the maximum deflection of the outer face-sheet (MDOF). A special MDOF (SMDOF) can be achieved by normalizing the MDOF with respect to the corresponding face-sheet radius and tube mass. Results confirm that the SMDOF of sandwich tubes is moderately sensitive to the core relative density, internal diameter, core thickness, and explosive charge. The finite element (FE) model was constructed using the Voronoi algorithm. After verifying the FE model, numerical studies were conducted to investigate the deformation process of sandwich tubes, the densification of double-layer cores, and the effects of core arrangement and face-sheet thickness on blast resistance. The SMDOF is influenced by the inner and outer face-sheets, whereas the special energy absorption (SEA) is mainly affected by the inner face-sheet.

      PubDate: 2017-06-02T12:58:22Z
       
  • Dynamic properties of carbon nanotubes reinforced carbon fibers/epoxy
           textile composites under low velocity impact
    • Abstract: Publication date: 15 September 2017
      Source:Composites Part B: Engineering, Volume 125
      Author(s): A. El Moumen, M. Tarfaoui, K. Lafdi, H. Benyahia
      In this study, the impact response of polymer composites containing a random distribution of carbon nanotubes (CNTs) has been investigated by considering energy profile diagrams and associated force-time curves. The composite consists of CNTs initially filled Epon 862 Epoxy resin and implanted between plies of T300 6k Carbon fiber with 5HS (satin) weave. Different mass fractions of CNTs were used: 0% as reference, 0.5%, 1%, 2% and 4%. Taylor impact test was used to obtain the impact response of specimens. Projectile manufactured from a high strength and hardened steel with a diameter of 20 mm and 1.5 kg of mass was launched by a compressed gas gun within the velocity of 7 m/s. Deformation histories and damage modes of specimens were recorded during impact using high-speed camera. The effect of CNTs amount on dynamic properties and damage process was discussed.

      PubDate: 2017-05-28T05:39:18Z
       
 
 
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