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ENGINEERING (1206 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 6)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 234)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 30)
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: 15)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access  
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)
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: 5)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
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: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 8)
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: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 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: 258)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 180)
Composites Part B : Engineering     Hybrid Journal   (Followers: 236)
Composites Science and Technology     Hybrid Journal   (Followers: 215)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 14)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 58)

        1 2 3 4 5 6 7 | Last

Journal Cover Composite Structures
  [SJR: 2.408]   [H-I: 92]   [258 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0263-8223
   Published by Elsevier Homepage  [3044 journals]
  • Free vibration analysis of thick viscoelastic composite plates on
           visco-Pasternak foundation using higher-order theory
    • Abstract: Publication date: 15 December 2017
      Source:Composite Structures, Volume 182
      Author(s): H.A. Zamani, M.M. Aghdam, M. Sadighi
      Free vibration of laminated viscoelastic composite plates on Pasternak viscoelastic medium with simply supported edge conditions is investigated. The composite plate consists of linear viscoelastic polymeric matrix reinforced by transversely isotropic elastic fibers. Multi-cell micromechanical approach together with relaxation functions of bulk/shear moduli and Boltzmann superposition principle are adopted to establish time-dependent stiffness coefficients of laminates. The coupled integro-PDEs of motions are derived based on third-order shear deformation theory by Laplace transformation and Hamilton principle. Complex frequencies and closed form solutions for transient response are achieved by weighted residual method, iterative numerical algorithm and Fourier transform. To verify, the results are compared for thick elastic composite plates on Pasternak elastic foundation and thick viscoelastic composite sandwich plates without foundation that represent acceptable accuracy. By parametric study, effects of materials, lamination scheme, geometry and medium on dynamic characteristics are scrutinized.

      PubDate: 2017-09-20T01:24:54Z
  • A review on additive manufacturing of polymer-fiber composites
    • Abstract: Publication date: 15 December 2017
      Source:Composite Structures, Volume 182
      Author(s): Pedram Parandoush, Dong Lin
      Additive manufacturing (AM) of polymer-fiber composites has transformed AM into a robust manufacturing paradigm and enabled producing highly customized parts with significantly improved mechanical properties, compared to un-reinforced polymers. Almost all commercially available AM methods could benefit from various fiber reinforcement techniques. Recent developments in 3D printing methods of fiber reinforced polymers, namely, fused deposition modeling (FDM), laminated object manufacturing (LOM), stereolithography (SL), extrusion, and selective laser sintering (SLS) are reviewed in this study to understand the trends and future directions in the respective areas. In addition to extra strength, fibers have also been used in 4D printing to control and manipulate the change of shape or swelling after 3D printing, right out of the printing bed. Although AM of fiber/polymer composites are increasingly developing and under intense attention, there are some issues needed to be addressed including void formation, poor adhesion of fibers and matrix, blockage due to filler inclusion, increased curing time, modelling, simulation, etc. Nonetheless, numerous innovative techniques were spotted amongst recent work trying to overcome these challenges with new material or manufacturing techniques.

      PubDate: 2017-09-20T01:24:54Z
  • Cyclic stress-strain model incorporating buckling effect for steel
           reinforcing bars embedded in FRP-confined concrete
    • Abstract: Publication date: 15 December 2017
      Source:Composite Structures, Volume 182
      Author(s): Yu-Lei Bai, Jian-Guo Dai, Togay Ozbakkaloglu
      Buckling of steel reinforcement usually causes a sudden loss of the load-carrying capacity and the ultimate state of conventional reinforced concrete (RC) cylinders. However, reinforcing bars behave differently in fiber-reinforced polymer (FRP)-confined RC cylinders due to the lateral confinement effect of FRP. This paper presents a theoretical study into the buckling behavior of longitudinal steel reinforcing bars embedded in FRP-confined concrete subjected to cyclic axial compression. An empirical monotonic compressive stress-strain model considering the buckling effects proposed previously for laterally supported reinforcing bars is extended to a cyclic model by combining the monotonic envelope and the Menegotto-Pinto model accounting for the cyclic loops. The cyclic stress-strain models for both laterally supported reinforcing bars and FRP-confined plain concrete are then implemented into the OpenSees software platform and validated through comparisons with compressive test results on cyclically loaded FRP-confined plain and RC cylinders. The proposed cyclic stress-strain model for laterally supported reinforcing bars is expected to serve as a fundamental model for predicting the seismic behavior of FRP-strengthened RC cylinders with widely-spaced transverse ties under cyclic axial compression, in which case the local buckling of reinforcing bars usually occurs between two adjacent transverse ties.

      PubDate: 2017-09-20T01:24:54Z
  • Effect of particle size on mixed-mode fracture of nanographene reinforced
           epoxy and mode I delamination of its carbon fiber composite
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Samit Roy, Abhishek Kumar
      Motivated by the lack of available mixed-mode test data in the literature on graphene nanocomposites, this article aims to investigate two cases: (a) the changes in mixed-mode fracture properties of a thermoset polymer (EPON 862) reinforced with hydrogen passivated nanographene platelets (HP-NGPs) and, (b) Mode I fracture properties of EPON 862/IM7 unidirectional laminate with dispersed HP-NGPs. For case (a), mixed mode fracture experimentation was performed using an asymmetric four-point bending specimen on baseline (0wt%), 0.1wt% and 0.5wt% HP-NGP reinforced EPON 862. Three different mode mix (KII/KI) ratios (0.78, 1.53, 117) were used to obtain a fracture envelop encompassing pure Mode I to Mode II. Remarkable increases in the fracture envelop both in Mode I (3 times) and Mode II (2.5 times) was observed with only 0.5wt% of HP-NGP. For case (b), Double Cantilever Beam (DCB) experiments were used to obtain the fracture toughness of the unidirectional IM7/EPON 862 laminates with the HP-NGP reinforced matrices. Significant increase (100%) in resistance to crack propagation in DCB specimens was observed. A brittle to ductile transition at the crack tip due to a novel nanoscale size effect is postulated and verified using TEM as the reason for the toughness increase.

      PubDate: 2017-09-20T01:24:54Z
  • Phase-field modelling of failure in hybrid laminates
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): R. Alessi, F. Freddi
      In this paper, the complex failure process of unidirectional hybrid laminates under uniaxial loading condition is reproduced and investigated by a one-dimensional phase-field model. The key ingredients of the approach, describing the mechanical response of a hybrid composite made of two different layers, are: (i) a phase-field method, based on a variational formulation of brittle fracture with regularised approximation of discontinuities for the two layers, (ii) cohesive law for the adhesive interface that connects the layers and (iii) robust and consolidated numerical strategy for the solution of the non-linear discretised problem. Explicit and well detailed simulations are shown for four peculiar failure mechanisms and the outcomes validated against experimental results available in literature. The model is able to discriminate among these different failure mechanisms according to the geometrical and mechanical properties of the hybrid composite. Both delamination of the adhesive interface is followed and crack patterns within the materials are fully determined. Finally, the proposed approach opens new perspective studies in higher dimension settings.

      PubDate: 2017-09-20T01:24:54Z
  • Aeroelastic behavior of stiffened composite laminated panel with embedded
           SMA wire using the hierarchical Rayleigh–Ritz method
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Odeny D. de Matos Junior, Maurício V. Donadon, Saullo G.P. Castro
      This work investigates the effects of temperature in the shape memory alloy hybrid composites (SMAHC) cylindrical stiffened panels’ aeroelastic stability. The SMAHC is modelled using a micromechanical formulation embedding carbon fiber, SMA wire and resin to the same lamina and taking into account the martensite/austenite phases of transformation in the material response. Virtual work principle formulation is implemented with classical laminate plate theory (CLPT) panel formulation and one-dimensional Euler-Bernoulli beam theory formulation for the stiffener. Numerical results are obtained by using an energy based semi-analytical method applying hierarchical polynomials to approximate the membrane and out of plane displacement fields. Different geometric configurations, laminate stacking sequences, boundary conditions and radii of curvature are investigated. The study shows that the variation of temperature induce stiffening due to changes in the martensite/austenite fractions of the SMA, increasing the critical flutter dynamic pressure. Therefore, it can be achieved certain control in the flutter critical boundary by increasing the temperature of the shape memory alloy (SMA) wire. The effects due to the SMA wire stiffening with the temperature are more pronounced for cross-ply stiffened cylindrical panels with unitary aspect ratio and for angle-ply panels with aspect ratio higher than one.

      PubDate: 2017-09-20T01:24:54Z
  • A modified V-notched beam test method for interlaminar shear behavior of
           3D woven composites
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Gang Liu, Li Zhang, Licheng Guo, Qimei Wang, Feng Liao
      The V-notched beam test (VNB) is recognized as a standard test method to determine the shear properties of composite materials. But it is not easy to make sure that the specimen placed in a predetermined position; the force conditions of the specimen become very complex when the large deformation of the specimen is generated, the friction between the internal components of fixture cannot be ignored when bending moment is generated as well when using traditional V-notched beam test fixtures. A modified V-notched beam test fixture has been proposed and designed based on standardized apparatus. After improvement, specimen with different thicknesses can be positioned easily. Meanwhile, effects of friction and bending moment are greatly reduced, and it has been validated by finite element simulation. Furthermore, some typical of experiments have been carried out by using the proposed fixture to determine the interlaminar shear modulus and shear strength of a type of 3D woven composites. Some new experimental data are presented in this paper, which can provide guidance and help for future study and industrial design of the 3D woven composites.
      Graphical abstract image

      PubDate: 2017-09-20T01:24:54Z
  • An experimental investigation on the bond behavior of steel reinforced
           polymers on concrete substrate
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Francesco Ascione, Marco Lamberti, Annalisa Napoli, Ghani Razaqpur, Roberto Realfonzo
      Steel Reinforced Polymer (SRP) systems have recently emerged as an attractive solution for the external strengthening of reinforced concrete structures. They entail unidirectional fabrics made out of high tensile strength steel cords that can be externally bonded to the substrate via wet lay-up, using either epoxy or polyester resin. Currently, research about the behavior of SRP strengthening systems for concrete structures is evolving but further systematic and comprehensive studies are still needed to ensure the consistency and reliability of the studies performed to date. The present paper contributes to expanding the existing knowledge by presenting the results of an extensive experimental program devoted to investigate the bond behaviour between SRP and concrete substrate. To this purpose, a number of SRP strips were bonded to concrete blocks by a thixotropic organic matrix and the lap joint was subsequently subjected to direct shear tests performed in displacement control. Besides the concrete strength, the following study parameters were considered: (a) the concrete surface roughness in the bonded region, (b) the density of the steel fabric, (c) the ratio of the epoxy covered concrete surface width to the SRP strip width, and (d) the bonded interface length.

      PubDate: 2017-09-20T01:24:54Z
  • Multi-scale design of three dimensional woven composite automobile fender
           using modified particle swarm optimization algorithm
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Wei Tao, Zhao Liu, Ping Zhu, Chao Zhu, Wei Chen
      This paper proposes a multi-scale modeling and optimization strategy for the lightweight design of automobile fenders made of three dimensional (3D) woven composite. A Multi-scale modeling approach is developed to predict the mechanical behaviors of the 3D woven composite fender with various design parameters from material and structure. In order to alleviate the computational cost, Kriging modeling technique is adopted to generate the surrogate models of structural responses under multiple load cases. An optimization method integrating modified particle swarm optimization algorithm and Kriging surrogate model is employed to find the optimal combination of continuous and discrete design variables from different scales. The optimized automobile fender achieves a 20.65% weight reduction when satisfying all requirements on structural stiffness under multiple load cases.

      PubDate: 2017-09-20T01:24:54Z
  • Third order theory based quadrilateral element for delaminated composite
           plates with a hybrid method for satisfying continuity at delamination
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Adnan Ahmed, Santosh Kapuria
      We present a four-node quadrilateral element based on the third order theory for analysis of composite plates with multiple delaminations, by employing a novel hybrid method for satisfying the continuity conditions at the delaminated fronts. In this method, the continuity of inplane displacement variables is satisfied by directly satisfying them at the midplanes of the sublaminates separated by delaminations, and employing the least squares method with respect to the shear rotation variables. The element is shown to yield very good accuracy in general, in comparison with experimental and three dimensional finite element (FE) solutions, and yield superior results to the other available analytical and FE solutions for static and free vibration responses of delaminated composite beams, and rectangular and skew composite plates under different boundary conditions. It is seen that the results from the existing continuity methods can have large error for thick beams/plates and for higher vibration modes, while the proposed hybrid method is generally very accurate and much superior to the existing methods.

      PubDate: 2017-09-20T01:24:54Z
  • Size effect on tensile strength of parallel CFRP wire stay cable
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Chengming Lan, Jingyu Wu, Nani Bai, Dan Qiang, Hui Li
      The paper studies the size effect on the tensile strength of parallel carbon fiber reinforced polymer (CFRP) wire stay cable in the macroscale. First, an asymptotic weakest-link Weibull model that incorporates a statistical length effect for the tensile strength of longitudinal composites is proposed in this research. For the proposed model, the weakest-link effect gradually becomes dominant and causes a decrease in strength that increases along the length of the longitudinal elements. The asymptotic threshold length L ρ on the strength analysis can be evaluated by the asymptotic weakest-link Weibull model. The strength data of single carbon fibers and impregnated bundles with different lengths obtained by previous studies are employed to validate the proposed model and the log-likelihood ratio test and the Bayesian information criterion (BIC) are used as the criteria for the validation of the proposed model. The tensile strengths of CFRP wires with different lengths are obtained and analyzed by using the proposed model, and the results obtained from the random strength field model proposed by Vořechovský and Chudoba are illustrated and discussed in detail. Finally, the actual strengths of two parallel CFRP wire cables are compared with the simulated results to illustrate the Daniels’ effect on the strengths of parallel CFRP wire cables. To evaluate the strengths of parallel CFRP wire stay cables, the length effect and Daniels’ effect should be considered in the design of the CFRP cables to ensure safety and reliability.

      PubDate: 2017-09-20T01:24:54Z
  • Geometrically nonlinear FE analysis of piezoelectric laminated composite
           structures under strong driving electric field
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Shun-Qi Zhang, Guo-Zhong Zhao, Shu-Yang Zhang, Rüdiger Schmidt, Xian-Sheng Qin
      To give a precise prediction of piezolaminated smart structures under strong electric field resulting in large displacements and rotations, the paper develops various geometrically nonlinear models with taking into account the electroelastic material nonlinear effect. The present nonlinear FE formulations are derived based on the first-order shear deformation theory (FSDT) with taking into account various geometric nonlinearities, which include von Kármán type nonlinearity, moderate rotation nonlinearity, and large rotation nonlinearity. The constitutive equations with consideration of piezoelectric material nonlinearity are integrated into the present FE formulations. The proposed nonlinear FE models are first validated by experimental and numerical examples in the literature, and later on implemented into numerical analysis for piezolaminated smart plates and shells with applied strong electric field.

      PubDate: 2017-09-20T01:24:54Z
  • Creep and creep buckling of pultruded glass-reinforced polymer members
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Kent A. Harries, Qi Guo, Daniel Cardoso
      This paper presents the results of an experimental program investigating flexural creep and creep buckling behavior of pultruded glass fiber reinforce polymer (pGFRP) plate specimens. In this study (a) short-term material properties were determined; (b) 1000h flexural creep tests at three load levels were conducted from which Findley power law parameters describing creep strain behavior were obtained; (c) creep buckling tests of slender concentrically loaded specimens were conducted; and (d) results from the buckling tests were compared with the predictions of the Findley power law which is shown to predict results reasonably well. Provided the flexural creep tests have relatively small loads and sufficient duration to pass through the primary creep stage of the material, reliable creep parameters were established. The intent of this study is to demonstrate a framework for establishing creep behavior and creep buckling performance of pGFRP materials.

      PubDate: 2017-09-20T01:24:54Z
  • Experimental and numerical study of strain-rate effects on the IFF
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Daniel M. Thomson, Hao Cui, Borja Erice, Justus Hoffmann, Jens Wiegand, Nik Petrinic
      A new implementation of Puck’s 3D Inter-Fibre Fracture criterion for unidirectional reinforced FRP laminates has been developed that improves the criterion in two main areas. First, a new treatment of strain rate effects on the inter-fibre fracture plane orientation has been included to improve the predictive capability of Puck’s criterion outside of the quasi-static loading regime. Secondly, a series of numerical optimisations have been made in an attempt to eliminate the additional computational cost of the fracture angle search, putting the cost of Puck’s criterion on par to much simpler alternatives (e.g. Hashin). An LS-DYNA user-defined material subroutine using this new implementation was developed and validated against a set of in-house high-rate SHPB tests on HexPly® IM7-8552 off-axis compression specimens at four different orientations, as well as literature data from Koerber et al. The results showed an improved ability to predict the fracture plane orientation at high strain rates and various benchmarking tests against a Hashin-based model showed only minor differences in computation time. Therefore, this new implementation successfully expands the validity of Puck’s IFF criterion into the dynamic loading range and eliminates its only major disadvantage, the cost of locating the critical fracture plane orientation.

      PubDate: 2017-09-20T01:24:54Z
  • Optimization of GFRP reinforcement in precast segments for metro tunnel
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Angelo Caratelli, Alberto Meda, Zila Rinaldi, Simone Spagnuolo, Giona Maddaluno
      The possibility of replacing the traditional steel reinforcement with glass fiber reinforced polymer (GFRP) cages in precast concrete tunnel segmental lining has been shown by the authors in previous papers. The use of GFRP rebars as structural reinforcement in precast tunnel segments, allows several advantages in terms of structural durability or in cases of temporary lining that will have to be demolished later. Furthermore, this reinforcement type can be a suitable solution to create dielectric joints, ensuring the interruption of possible stray currents, which often lead to corrosion problems. Nevertheless, this peculiar application requires curvilinear shape of the reinforcement, and then different production process and rebar geometries. In the present work, a suggestion for the optimization of the GFRP reinforcement for tunnel segment is given. Four different GFRP cage typologies are analysed and applied as a reinforcement in full-scale tunnel segments. Both bending and point load tests are developed and the structural performances of the specimens are compared and discussed. Finally, the best solution, in terms of cost-benefit analysis is proposed.

      PubDate: 2017-09-20T01:24:54Z
  • Computationally efficient, high-fidelity micromechanics framework using
           refined 1D models
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): I. Kaleel, M. Petrolo, A.M. Waas, E. Carrera
      A novel micromechanical framework based on higher-order refined beam models is presented. The micromechanical framework is developed within the scheme of the Carrera Unified Formulation (CUF), a hierarchical formulation which provides a framework to obtain refined structural theories via a variable kinematic description. The Component-Wise approach (CW), a recent extension of one-dimensional (1D) CUF models, is utilized to model components within the representative volume element (RVE). CW models employ Lagrange-type polynomials to interpolate the kinematic field over the element cross-sections of the beams and efficiently handle the analysis of multi-component structures such as RVE. The governing equations are derived in the weak form using finite element method. The framework derives its efficiency from the ability of CUF models to produce accurate 3D displacement and stress fields at a reduced computational cost. Three different cases of micromechanical homogenization are presented to demonstrate the efficiency and high-fidelity of the proposed framework. The results are validated through published literature results and via the commercial software ABAQUS. The capability of CUF-CW models to accurately predict the overall elastic moduli along with the recovery of local 3D fields is highlighted.

      PubDate: 2017-09-20T01:24:54Z
  • Corrigendum to “Large deflection analysis of planar curved beams made of
           Functionally Graded Materials using Variational Iterational Method”
           [Compos Struct 136 (2016) 204–216]
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Ugurcan Eroglu

      PubDate: 2017-09-20T01:24:54Z
  • Small perforations in corrugated sandwich panel significantly enhance low
           frequency sound absorption and transmission loss
    • Abstract: Publication date: 15 December 2017
      Source:Composite Structures, Volume 182
      Author(s): H. Meng, M.A. Galland, M. Ichchou, O. Bareille, F.X. Xin, T.J. Lu
      Numerical and experimental investigations are performed to evaluate the low frequency sound absorption coefficient (SAC) and sound transmission loss (STL) of corrugated sandwich panels with different perforation configurations, including perforations in one of the face plates, in the corrugated core, and in both the face plate and the corrugated core. Finite element (FE) models are constructed with considerations of acoustic-structure interactions and viscous and thermal energy dissipations inside the perforations. The validity of FE calculations is checked against experimental measurements with the tested samples provided by additive manufacturing. Compared with the classical corrugated sandwich without perforation, the corrugated sandwich with perforated pores in one of its face plate not only exhibits a higher SAC at low frequencies but also a better STL as a consequence of the enlarged SAC. The influences of perforation diameter and perforation ratio on the vibroacoustic performance of the sandwich are also explored. For a corrugated sandwich with uniform perforations, the acoustical resonance frequencies and bandwidth in its SAC and STL curves decrease with increasing pore diameter and decreasing perforation ratio. Non-uniform perforation diameters and perforation ratios result in larger bandwidth and lower acoustical resonance frequencies relative to the case of uniform perforations. The proposed perforated sandwich panels with corrugated cores are attractive ultralightweight structures for multifunctional applications such as simultaneous load-bearing, energy absorption, sound proofing and sound absorption.

      PubDate: 2017-09-14T08:08:21Z
  • Acoustic scattering from immersed composite cylindrical shells: Existence
           of zero group velocity circumferential waves
    • Abstract: Publication date: 15 December 2017
      Source:Composite Structures, Volume 182
      Author(s): Said Agounad, El Houcein Aassif, Younes Khandouch, Dominique Décultot, Gérard Maze, Abdelkader Elhanaoui
      Some Lamb waves in a plate and some circumferential waves in a one-layer cylinder are characterized by the resonance frequencies where the group velocity is vanishing while the phase velocity remains finite. This paper investigates on the existence of these special waves which call zero group velocity waves (ZGV waves) in the case of the copper/polymer composite cylindrical shell immersed in water and filled with air. The acoustic scattering of a plane wave from this composite cylindrical shell is analyzed in the reduced frequency range ( 0.1 < k 1 a 1 < 200 ; k 1 is the wave number and a 1 is the outer radius of the composite cylindrical shell). The study of the respective influence of the inner layer thickness (polymer) and the outer layer thickness (copper) shows that the existence of these waves is a function of these thicknesses. Moreover, this study depicts that the dispersion curves of the considered bilayer shell tend towards the dispersion curves of the one-layer cylindrical shell made from the material of the thicker layer of the bi-layer cylindrical shell (polymer or copper). The time-frequency representation of smoothed pseudo Wigner-Ville (SPWV) is used to extract some properties of the circumferential waves propagating in and around the bi-layer cylindrical shell. The obtained results by this representation are in good agreement with those obtained by the theoretical approach.

      PubDate: 2017-09-14T08:08:21Z
  • Sensing capabilities of carbon based TRC beam from slack to pull-out
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Y. Goldfeld, T. Quadflieg, T. Gries
      The paper explores the sensing capabilities of a carbon based textile reinforced concrete (TRC) composite element to monitor its structural mechanisms. The concept is based on continuous carbon rovings knitted into glass textile mesh that simultaneously serve as the structural reinforcement and as the sensory system. The loading procedures which starts from a healthy state, to micro and macro cracked state, and ends with a completely pull-out of the tensioned rovings is strongly affected by the micro-structural mechanism of the carbon rovings within the concrete matrix. It is found that the measured electrical resistance is characterized by this mechanism and can reflect the structural condition. Therefore, it can serve as a structural health monitoring system. The paper demonstrates these sensing capabilities along the entire range of the loading procedure, even up to progressive failure mechanism, where traditional sensing devices usually failed to produce meaningful information.

      PubDate: 2017-09-14T08:08:21Z
  • Correlation of drilling damage with mechanical strength: A geometrical
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Jorge Miguel Silva, Filipe Ferreira, Stella M. Abreu, João E. Matos, Luís Miguel P. Durão
      Nowadays composites are one of the most interesting groups of materials with applications in several technologically advanced fields like aeronautics, automotive or medicine among others. The great demand for this material comes from its low weight and high specific strength resulting in a good option for several demanding uses. One of the main advantages is related to the ability to produce parts in a near-net shape. However, assembly requirements normally include secondary operations like drilling. The resulting damage can affect the mechanical properties of the material questioning product reliability. In this work the authors present a comparative study of different combinations of tools, cutting speeds and feed rates associated with a method of image analysis that includes fractal dimension, a geometrical feature of the damaged region. This mathematical feature accounts for the irregularity of the damage boundary that can act as a stress concentration factor, thus causing mechanical strength reduction. Results include the presentation of a damage assessment model that could help on the correlation between the damaged region and the mechanical properties, including the contribution of the fractal dimension.

      PubDate: 2017-09-14T08:08:21Z
  • Construction of second gradient continuum models for random fibrous
           networks and analysis of size effects
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): K. Berkache, S. Deogekar, I. Goda, R.C. Picu, J.-F. Ganghoffer
      In this work we develop anisotropic first and second order displacement gradient linear elastic continuum models for two-dimensional random fiber networks. The continuum constitutive parameters are evaluated based on the response of the explicit representation of the network in which each fiber is a beam and the fibers are connected at crossing points with welded joints. The scaling of the first and second order moduli with the network parameters, such as the network density and the ratio of the fiber bending to axial stiffness, is determined. We observe that the dependence of the second gradient moduli on these two parameters is similar to the dependence of the classical moduli on the same parameters. The internal length scales associated with the gradient terms of the constitutive equation are also defined in terms of the network parameters. The influence of the model size on the elastic constants is discussed. We observe that if the model size is large enough for the classical moduli to be size effect free. However, there is still a strong size dependency of the computed internal lengths associated to second order gradient effects.

      PubDate: 2017-09-14T08:08:21Z
  • Numerical modeling and analysis for axial compressive crushing of randomly
           oriented thermoplastic composite tubes based on the out-of-plane damage
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Tsuyoshi Matsuo, Mitsuharu Kan, Kenichi Furukawa, Takuya Sumiyama, Hiroshi Enomoto, Keisuke Sakaguchi
      The structural beams with a uniform cross section of hat-shape were manufactured through a high-cycle compression molding technique, by using randomly oriented chopped thermoplastic composites. The crash tubes were obtained by vibration welding of those two hat-section beams at their flanges. And the axial compressive impact tests were carried out for them. It followed that the compressive failure was progressive crushing caused by the delamination and local buckling of walls and welded flange while the specific energy absorption was so high. The finite element model was constructed to predict the axial progressive crushing and energy absorption. The important key concept for designing the numerical model was to incorporate some hypothetical inter-layers even in randomly oriented composites and assign them with the failure model as cohesive zone elements, which can perform non-linear characteristics with failure criterion. The material parameters for the model tried to be obtained by direct measurement test methods. The reproducibility of the numerical modeling was validated against the results from axial compressive crushing. The progressive damage mode and energy absorption prediction agreed well with the experimental results. It was also clarified that the out-of-plane failure influenced the energy absorption performance of the crash tubes.

      PubDate: 2017-09-14T08:08:21Z
  • The influence of through-thickness reinforcement geometry and pattern on
           delamination of fiber-reinforced composites: Part II – Modeling
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Georgios Pappas, Simon Joncas, Véronique Michaud, John Botsis
      This article reports modeling techniques and results based on experimental Mode I characterization of a layered woven GFRP material with tufting reinforcement. Standard tuft and loop-less geometries are investigated on three different areal patterns to evaluate their effects on fracture resistance. The experiments reveal that tow/ply and tuft bridging phenomena are present during delamination. The numerical modeling comprises cohesive elements for tow/ply bridging and 1D connector elements for discrete tufts. The traction separation relations for the cohesive model are acquired using an inverse scheme based on strain measurements and the force-separation relations of tuft’s failure mechanisms from uniaxial pulling tests on a reference tufting pattern. Results show that tuft’s failure mechanism is strongly affected by tufting pattern and geometry while tow/ply bridging contributes 20–30% of the overall fracture energy. The energy absorbed by pull-out of loop-less tufts is approximately twice the fracture energy of standard ones with pull-out triggering much more extensive tow/ply bridging phenomena.

      PubDate: 2017-09-14T08:08:21Z
  • Material parameter identification of the elementary ply damage mesomodel
           using virtual micro-mechanical tests of a carbon fiber epoxy system
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): D. Garoz, F.A. Gilabert, R.D.B. Sevenois, S.W.F. Spronk, W. Van Paepegem
      A general multiscale hierarchical framework is proposed to identify the material parameters of a mesoscale model using numerical simulations based on virtual micro-mechanical tests. The identification of the material parameters is usually done with several experiments on different laminates. These experiments are replaced by virtual tests on a microscale finite element model with the same load conditions than the real experiments. The microscale model represents the unidirectional ply geometry based on its constituents, fibers and matrix, with their corresponding properties and the damage behavior of the matrix and interface between them. Under the defined load conditions, the homogenized stress-strain behavior of the laminates is obtained and then, the constitutive model parameters of the ply damage mesomodel are identified. As an example, the proposed framework is applied to identify the material parameters of the elementary ply damage mesomodel developed at LMT-Cachan. It is shown that, when the materials, geometry and load conditions are correctly defined in the micromodel, the real experiments can be replaced by virtual tests. As a result, the amount of experiments can be reduced saving costs and time. In addition, further studies can use the proposed methodology based on virtual micro-mechanical tests to improve the current mesoscale models.

      PubDate: 2017-09-14T08:08:21Z
  • Experimental and numerical analysis of Carbon Fiber Reinforced Polymer
           notched coupons under tensile loading
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Joël Serra, Christophe Bouvet, Bruno Castanié, Caroline Petiot
      The behavior of composite laminates subject to notch based stress concentrations is difficult to apprehend, especially the mechanisms of damage progression leading to total failure. Numerical and experimental investigations were carried out on three different stacking sequences of notched, thin ply carbon/epoxy laminates. This paper presents a computational study of notched tensile tests (U-notch) using the Discrete Ply Modeling (DPM) method, which has already proved efficient on both in-plane and out-of-plane loading cases, such as pull through, low velocity impact and compression after impact. The specificities of this finite element model are its discrete nature (interface elements to model delamination and matrix cracks), the small number of parameters required, and its robustness. This work follows on from the study of open-hole tensile tests (same three layups) by the same authors [1] and analyzes the influence of layup and notch shape. Comparisons with experiments (using infrared technology) demonstrate that tensile strengths, and failure scenarios and patterns are predicted with acceptable accuracy.

      PubDate: 2017-09-08T06:32:54Z
  • A model of low-velocity impact damage of composite plates subjected to
           Compression-After-Impact (CAI) testing
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): P. Rozylo, H. Debski, T. Kubiak
      The paper presents a simplified model of damage of composite plates (SDM) subjected to low-velocity impact testing. The damage model assumes reduced thickness of laminate plies versus impact energy. The decrease in strength of the lay-up was measured by Compression-After-Impact (CAI) tests. The numerical analysis was performed on composite plates made of CFRP laminate subjected to uniform compression, with represented regions of damage caused by different impact energies. The numerical results show the behaviour of the laminate during compression, taking into account the damage process evaluated by a progressive damage criterion. The numerical analysis was performed using the ABAQUS® programme. The results were verified based on experimental findings reported in the literature and the numerical results of the tested composite plates subjected to CAI testing.

      PubDate: 2017-09-08T06:32:54Z
  • Thermal buckling analysis of cylindrical shell with functionally graded
           material coating
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Quanfeng Han, Zewu Wang, David H. Nash, Peiqi Liu
      As an excellent heat-resistant material with broad potential application, the mechanical behavior of functionally graded material (FGM) is of research focus in many fields. However, the thermal buckling behavior of FGM thin-walled shell has been widely investigated, but little work was done for the cylindrical shell with FGM coating due to more complex material distribution and mathematical expressions. Therefore, the present work mainly carried out the theoretical derivation and buckling behavior analysis for a cylindrical shell with FGM coating subjected to a thermal load. The results show that the theoretical solution of the critical buckling temperature rise is in good agreement with the developed numerical approach. In addition, an empirical engineering formula of the critical buckling temperature rise with a more concise mathematical expression is proposed for solving this practical complex engineering application based on the significant amount of numerical calculation and theoretical analysis.

      PubDate: 2017-09-08T06:32:54Z
  • Study on impact damage mechanisms and TAI capacity for the composite scarf
           repair of the primary load-bearing level
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Bin Liu, Fei Xu, Jian Qin, Zhixian Lu
      As composite material plays a leading role in aircraft, composite bonding repair has been extensively applied. Among composite bonding repairs, the scarf bonding repair is widely adopted and has high repair efficiency especially in primary load-bearing structures. However, the impact damage tolerance and impact damage mechanisms were not considered for repaired structure integrity design yet. This paper experimentally and numerically studied the scarfed bonding repair of the advanced CFRP, which may suffer a low velocity impact load in service. At the central location of adhesive zone, impact energy and response regularity were studied to reveal the competition failure mechanism for inner kinds of materials. In the impact procedure, double force peaks phenomenon and four typical phases were found. Tension after impact (TAI) capacities were also tested to explain the impact damage effects on residual strength. The adhesive damage has strong influence over tension after impact capability. The most easily broken location in the bonded zone is the feathered tip on the back of impact point. The critical impact energy 23J exists for this size of specimen. When the impact energy is higher than the critical 23J, except for the composites damage, the adhesive damage can be observed at the second force dropping. The scarfed adhesive damage occurred at the scarf feathered tip of back side.

      PubDate: 2017-09-08T06:32:54Z
  • Post-buckling analysis of refined shear deformable graphene platelet
           reinforced beams with porosities and geometrical imperfection
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Mohammad Reza Barati, Ashraf M. Zenkour
      In this paper, post-buckling behavior of geometrically imperfect porous beams reinforced with graphene platelets (GPLs) and resting on nonlinear hardening foundation is investigated. GPLs are uniformly and non-uniformly distributed thorough the thickness direction. Different porosity distributions called uniform, symmetric and asymmetric are considered. The elastic properties of the nanocomposite are obtained by employing Halpin-Tsai micromechanics model. The present refined beam model satisfies the shear deformation effect needless of any shear correction factor. The post-buckling load-deflection relation is obtained by solving the governing equations having cubic nonlinearity applying Galerkin’s method needless of any iteration process. New results show the importance of porosity coefficient, porosity distribution, GPL distribution, GPL weight fraction, geometrical imperfection and foundation parameters on nonlinear buckling behavior of porous beams. Specially, porosities and GPL reinforcement have a great impact on post-buckling configuration of both ideal and imperfect nanocomposite beams.

      PubDate: 2017-09-08T06:32:54Z
  • Lightning strike resistance of an electrically conductive CFRP with a
           CSA-doped PANI/epoxy matrix
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Andrzej Katunin, Katarzyna Krukiewicz, Roman Turczyn, Przemysław Sul, Krzysztof Dragan
      An analysis of a structural damage extent of a developed electrically conductive CFRP composite exposed to the high-current electrical discharges simulating lightning strikes was conducted in order to evaluate its ability of carrying on lightning electrical current and its damage resistance during lightning events. The composite was fully fabricated from organic compounds, i.e. electrically conductive polymer blend of polyaniline (PANI) doped with camphorsulfonic acid (CSA) and epoxy resin, and carbon fabric used both as a mechanical reinforcement as well as supporting electrical conductor for ensuring adequate electrical conductivity and mechanical properties. An investigation of lightning strike resistance was performed during high-voltage and high-current mode tests. For preliminary evaluation the resulting damage was examined using visual inspection. Furthermore, the ultrasonic testing and X-ray computed tomography were applied for evaluation of degradation mechanisms occurring during a typical lightning strike event. The obtained results show that the developed composite is characterized by good electrical conductivity and mechanical properties and may successfully resist high-current impulse discharges typical for lightning strike events. Therefore, the developed composite can be considered asa potential candidate for a lightning strike protection material in aircraft industry and other applications.

      PubDate: 2017-09-08T06:32:54Z
  • Long-term design of FRP-PUR web-core sandwich structures in building
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Sonia Yanes-Armas, Julia de Castro, Thomas Keller
      The structural behavior of GFRP-polyurethane (PUR) web-core sandwich structures subjected to sustained loading was investigated. As a basis, a study of the mechanical behavior of rigid PUR foams used as core materials was conducted, with emphasis on creep. The study showed that the foam anisotropy, its density and the loading type applied must be considered to assess the structural performance of the GFRP-PUR web-core sandwich. The influence of creep on the web-core interaction, i.e. on the shear load distribution and local instability phenomena were then analyzed. The effects of applying particular design recommendations on the design were assessed based on the example of a real GFRP-PUR sandwich roof. The design shear resistance of the GFRP webs, their dimensions and governing failure mode significantly depended on the applied recommendation. A design procedure to evaluate the overall shear resistance of the GFRP-PUR core over time, taking into account creep effects, was presented.

      PubDate: 2017-09-08T06:32:54Z
  • Buckling optimization of variable-stiffness composite panels based on flow
           field function
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Peng Hao, Chen Liu, Xiaojie Yuan, Bo Wang, Gang Li, Tianyu Zhu, Fei Niu
      Due to the non-uniform in-plane stress distribution, variable-stiffness panel with curvilinear fiber paths is a promising structural concept for cutout reinforcement of composite structures under axial compression, due to the more diverse tailorability opportunities than simply choosing the best straight stacking sequence. However, traditional representation methods of curvilinear fiber path are usually not flexible for cutout reinforcement. In this study, the flow field function containing a uniform field and several vortex fields is utilized to represent the fiber path due to its inherent non-intersect and orthotropic features, and a bi-level optimization framework of variable-stiffness panels considering manufacturing constraints is then proposed. A typical rectangular composite panel with multiple cutouts is established to demonstrate the advantage of proposed framework by comparison with other fiber path functions. Results indicate that the flow fiber path only needs few variables to finely represent the fiber path, which can provide satisfying and manufacturable fiber paths by combination use of curvature constraint.

      PubDate: 2017-09-08T06:32:54Z
  • Probabilistic sensitivity analysis to understand the influence of
           micromechanical properties of wood on its macroscopic response
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): P.O. Hristov, F.A. DiazDelaO, E.I. Saavedra Flores, C.F. Guzmán, U. Farooq
      This paper investigates the influence of the uncertainty in different micromechanical properties on the variability of the macroscopic response of cross-laminated timber plates, by means of a probabilistic sensitivity analysis. Cross-laminated timber plates can be modelled using a multiscale finite element approach which although suitable, suffers from high computational cost. Investigating parametric importance can incur considerable time penalty since conventional sensitivity analysis relies on a large number of code evaluations to produce accurate results. In order to address this issue, we build a statistical approximation to the code output and use it to perform sensitivity analysis. We investigate the effect of a collection of parameters on the density and Young’s moduli of wood. Additionally, the influence on the response of cross-laminated timber plates subject to bending, in-plane shear and compression loads is investigated due to its relevance within the engineering community. The presented results provide a practical insight into the importance of each micromechanical parameter, which allows research effort to be focused on important wood properties.

      PubDate: 2017-09-08T06:32:54Z
  • Creep and recovery of viscoelastic laminated composite plates
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Jafar Rouzegar, Mohammad Gholami
      In this study, the dynamic relaxation method is employed for higher-order bending analysis of isotropic and viscoelastic laminated composite plates. Using Prony series, a linear viscoelastic model, is considered for material behavior. The displacement field is expressed according to two-variable refined plate theory. This simple higher-order shear deformation theory, which involves only two unknown functions, predicts parabolic variation of transverse shear stresses across the plate thickness and satisfies the zero traction condition on the plate surfaces. Virtual work principle is employed to derive the governing equations. Time integrals are approximated by trapezoidal rules and the dynamic relaxation method combined with finite difference technique is used in order to solve governing equations. Creep and recovery of isotropic and laminated plates are studied under various loadings. Efficiency and accuracy of present formulation is proved by solving several benchmark problems. The effects of different parameters such as side-to-thickness ratio, types of loadings and boundary conditions, and stacking sequence are investigated on the behavior of viscoelastic laminated composite plates.

      PubDate: 2017-09-08T06:32:54Z
  • Influence of double hooked-end steel fibers and slag on mechanical and
           durability properties of high performance recycled aggregate concrete
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Vahid Afroughsabet, Luigi Biolzi, Togay Ozbakkaloglu
      This paper presents a study on the properties of sustainable high performance steel fiber-reinforced concretes that were manufactured with recycled concrete aggregates (RCA). Natural coarse aggregates were replaced by RCA derived from parent concretes with compressive strengths of 40 and 80MPa at volume replacement ratios of 50% and 100%. High performance concretes (HPC) were manufactured using double hooked-end steel fibers added at a fiber volume fraction of 1%, and in some of the mixes 30% of ordinary Portland cement was replaced by slag. Along with their mechanical properties, the water absorption, electrical resistivity, and shrinkage of the concrete mixes were evaluated. The results indicate that HPC with desirable properties can be produced using RCA derived from a high-strength parent concrete. The addition of steel fibers significantly increases the mechanical properties of recycled aggregate concretes. Replacing natural aggregates with RCA of lower strength adversely affects the durability properties of the concrete. However, concretes produced with a higher quality RCA and those containing slag and steel fibers exhibit reduced water absorption and shrinkage compared to plain natural aggregate concrete. The findings of this research are highly promising for the development of HPC with reduced environmental impact.

      PubDate: 2017-09-08T06:32:54Z
  • An experimental study of scaling effects in the perforation resistance of
           woven CFRP laminates
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): Z.W. Xu, Z.W. Guan, W.J. Cantwell
      Scaling effects in the perforation resistance of a carbon fibre-reinforced polymer (CFRP) composite have been investigated under quasi-static and low velocity impact loading conditions. The perforation data have been supplemented with results from additional flexural tests on scaled composite beams, which highlighted a decrease in both strength and failure strain as scale size increases. Strain-rate effects in this composite have been also identified, with the plates absorbing less energy as the loading-rate is increased. Tests on scaled plates have shown that the normalised perforation energy increases rapidly with scale size. An examination of the load-displacement response indicates that the elastic response obeys a simple scaling law, whereas that the damage does not. It was found that fibre damage was more severe in larger composite panels. It is argued that the energy absorbed in fibre fracture does not scale in the expected manner, leading to greater levels of fibre damage in the larger plates.

      PubDate: 2017-09-08T06:32:54Z
  • Short-fibre hybrid polypropylene composites reinforced with PET and Rayon
           fibres – Effects of SSP and interphase tailoring
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): P. Franciszczak, R. Merijs-Meri, K. Kalniņš, A.K. Błędzki, J. Zicans
      This research focused on manufacturing of light-weight hybrid polypropylene composites reinforced with short fibres from polyterephthalate and rayon-viscose yarns. The aim of hybridisation of reinforcements was to improve some aspects of mechanical performance of these composites and to reduce their cost. For the first reason also three methods of fibre-matrix interphase tailoring and solid state polycondensation of PET fibres were applied and investigated in terms of influence on their strength, moduli and impact behaviour of composites. Lower density of PET and rayon-viscose fibres in comparison to glass fibres had to a large degree compensated the specific properties of manufactured hybrids. The same level of drop-weight impact energy absorption was achieved for hybrids as for their PP-GF counterpart, while merely 25% lower specific flexural strength was obtained. The HDT was only ∼15 degrees lower. Therefore the developed composites may substitute a standard PP-GF in some particular lightweight applications. The results give also insight into properties and mechanical behaviour of applied fibres and how they can be altered during processing.

      PubDate: 2017-09-02T15:56:38Z
  • Gradient enhancement of a transversely isotropic continuum damage model
    • Abstract: Publication date: 1 December 2017
      Source:Composite Structures, Volume 181
      Author(s): J. Läufer, V. Becker, W. Wagner
      In order to reduce weight and to create efficient construction, fiber reinforced plastics are of general interest. Hence, the understanding of the material behavior is very important to build safe structures. For composite structures, existing of several stacked layers, which behave transversely isotropic, different failure mechanisms may appear. The considerations in this paper deal with the failure analysis of one layer of a laminated structure with unidirectionally orientated fibers. The possible failure mechanisms are described with failure criteria. So-called damage models include these criteria and the behavior of damaged structures, formulated in degradation models. Damage models usually show a strong mesh dependency in their inelastic part, which begins with an initial failure in the structure and ends with the total loss of stiffness. This mesh dependency is characterized by the concentration of the occurring damage only within a small zone, which generally corresponds e.g. with one element row and thus with the mesh refinement. In order to develop a regularized damage model for transversely isotropic materials a gradient enhancement based on the Helmholtz free energy function is used. With the introduction of a new field, coupled with the inelastic variables, the model gets a non-local character, preserving C 0 -interpolation order. Formulated as a pure minimization problem, the elimination of the mesh dependency due to the unambiguity of the solution is illustrated by numerical examples.

      PubDate: 2017-09-02T15:56:38Z
  • Characterization of failure mechanisms of composite structures subjected
           to fatigue dominated by the self-heating effect
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Andrzej Katunin, Angelika Wronkowicz
      A self-heating effect in a non-stationary regime is a very dangerous phenomenon occurring in polymeric composites during cyclic loading, which significantly intensifies a degradation process and leads to a catastrophic failure of the loaded structure. In this paper, the authors performed fatigue tests until achieving various self-heating temperature values on the tested specimens’ surfaces, and further inspection using the X-ray computed tomography. The developed image processing algorithm allows for extraction and classification of different types of damage. The obtained results allow precise determining of a critical self-heating temperature due to a very high accuracy of the applied method as well as describing in detail a degradation mechanism of a polymeric composite structure subjected to fatigue with the accompanying self-heating effect. It was also possible to combine observed events in the temperature and acoustic emission evolution with an appearance of structural damage in the tested structures and describe a general phenomenology of the degradation process of composite structures working in such conditions. The obtained results allow for improvement of design requirements of composite structures working in mechanical fatigue conditions as well as proper maintenance of composite constructions in order to avoid critical ranges of generated heat during cyclic loading.

      PubDate: 2017-09-02T15:56:38Z
  • Engineering properties of CFRP laminate under high strain rates
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Alaa Al-Mosawe, Riadh Al-Mahaidi, Xiao-Ling Zhao
      This paper presents the results of experimental investigations of the tensile properties of different types of CFRP plates. Coupon specimens of low, normal and ultra-high modulus CFRP plates were prepared and tested under tensile loading. Four different strain rates were used, including one low strain rate and three high strain rates. Two methods of capturing strain were used: image correlation photogrammetry and foil strain gauges. The results showed a significant increase in the tensile strength, ultimate strain and elastic modulus for coupons under high strain rates. The CFRP coupons were prepared and tested in accordance with the ASTM3039-08 standards. Finite element analysis was performed and the results agreed very well with the experimental results.

      PubDate: 2017-09-02T15:56:38Z
  • Efficient near surface mounted CFRP shear strengthening of high strength
           prestressed concrete beams – An experimental study
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Vikas Singh Kuntal, Maheswaran Chellapandian, Shanmugam Suriya Prakash
      Shear behavior of prestressed concrete members and its strengthening is complex due to its brittle nature of failure and a number of variables affecting its behavior. The main goal of this investigation is to assess the efficiency of different near surface mounted (NSM) strengthening configurations using CFRP (Carbon Fiber Reinforced Polymer) laminates on the shear behavior of prestressed concrete beams. The parameters considered in this study are (i) the presence of vertical stirrups and (ii) different NSM FRP shear strengthening configurations. Twelve prestressed concrete beams with and without vertical stirrups were cast and strengthened using different NSM CFRP configurations and tested under shear. All the beams were tested under three point bending at a shear span to depth (a/d) ratio of 2.5 to simulate the shear dominant behavior. Test results revealed that NSM strengthening of prestressed concrete beams using CFRP laminates at 45° was more efficient in improving the shear capacity of beams with and without vertical stirrups. It was also observed that the shear mode of failure could be converted to the flexural mode with improved ductility by designing a suitable NSM shear-strengthening scheme. Shear strength calculations of NSM strengthened beams were made using ACI codes and other analytical models. ACI calculations were found to be conservative in estimating the shear contribution of NSM laminates.

      PubDate: 2017-09-02T15:56:38Z
  • Numerical study of the Time-of-Flight Pulsed Ultrasonic Polar Scan for the
           determination of the full elasticity tensor of orthotropic plates
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): A. Martens, M. Kersemans, J. Daemen, E. Verboven, W. Van Paepegem, J. Degrieck, S. Delrue, K. Van Den Abeele
      A novel approach is presented for the ultrasonic determination of the elastic constants in plate-like structures of an orthotropic material (e.g. composites) using a Time-of-Flight version of the Pulsed Ultrasonic Polar Scan (TOF P-UPS). A forward numerical model of the TOF P-UPS is coupled to an inversion algorithm, based on the genetic optimization principle, targeting the determination of the orthotropic elastic parameters, and the quality of the inversion is demonstrated for synthetic data representative for composites. The advantage of the new approach is that the presented TOF P-UPS inversion method does not require a priori knowledge about the symmetry class of the material, nor about the orientation of the main axes of symmetry. Furthermore, the TOF P-UPS inversion method yields an accurate characterization of the orthotropic elasticity tensor, even when applied to composite plates with small frequency-thickness ratios in which the traditional bulk wave approaches no longer hold. Finally, the robustness of the TOF P-UPS inversion method is demonstrated for noisy data by evaluating the results for a range of signal-to-noise ratios.

      PubDate: 2017-09-02T15:56:38Z
  • Subcomponent development for sandwich composite wind turbine blade bonded
           joints analysis
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Garbiñe Fernandez, Hodei Usabiaga, Dirk Vandepitte
      In the sector of wind energy, the trend to increasing turbine size is ongoing and it will continue to do so. This research focuses explicitly on a particular aspect of structural design which is reported to be very critical in many designs of wind turbine blade wing box structures, namely the connection between the spar web and the spar cap, which are usually built up with sandwich materials. A pyramid structured approach is developed which links local phenomena of stress transfer and failure in the adhesive connection to overall loads on the entire machine. This paper focuses on the subcomponent level of the pyramid scheme and it shows the relevance of investigations and experiments on this level. A specific test structure is designed and manufactured as a C-beam to reproduce load transfer phenomena as they occur in real blades. An experimental test campaign is conducted using different data acquisition principles and sensors to monitor structural behaviour. Results from a finite element model are compared to experimental results and satisfactory results are obtained.

      PubDate: 2017-09-02T15:56:38Z
  • Exploring damage kinetics in short glass fibre reinforced thermoplastics
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Hedi Nouri, Sofiane Guessasma, Frederic Roger, Abderrahmane Ayadi, Habibou Maitournam
      In situ SEM tensile tests are performed to shed more light on the onset and damage evolution in the shell layer of a short glass fibre reinforced polyamide 6.6 (SGFRP) composite obtained by injection moulding. Damage mechanisms are studied in three different loading directions including 0°, 45° and 90° with respect to the mould flow direction (MFD). The development of damage is monitored until total failure at different scales of observation. Qualitative results indicate that the orientation of tensile specimens with respect to the mould direction determines to a large extent the nature of involved damage mechanisms. Interfacial damage is by far the leading damage mechanism. Quantitative investigation further indicates multi-stage damage kinetics, which demonstrates an asymmetric behaviour with respect to sample orientation. One to two main directions of damage growth are identified as responsible for the failure properties of the studied composite depending on sample orientation.

      PubDate: 2017-09-02T15:56:38Z
  • Relative behaviour of premature failures in adhesively plated RC beam
           using controllable and existing parameters
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Mohammad Arsalan Khan, Jamal El-Rimawi, Vadim V. Silberschmidt
      Retrofitting of RC beam by gluing a steel plate at the soffit has been a widely adopted technique due to its ease of use, calculations and having minimal variations on structural aesthetics; hence, a large number of such retrofitted structures exist today. However, such structures have also failed frequently due to the formation of premature failures such as peeling and debonding. The further investigations conducted in literature indicated that such undesirable failures can be effected by a large number of geometrical and material parameters. Although, the characterisation and relative influence of such parameters on modes of failures remain unknown; as the past studies have been largely case sensitive or focussing on a small set of parameters. Therefore, to address these issues, a simple but focussed numerical model has been validated through literature for multiple modes of failures over wide range of possible parameters. Further, targeting the response of beam and its critical locations, the authors of this study suggest that the understanding of relative impact of effective parameters, in terms of beam capacity and brittleness of modes of failure, can be broadly utilised to re-evaluate the cause(s) of failure(s) through case studies, or to predict the future of retrofitted structures/beams.

      PubDate: 2017-09-02T15:56:38Z
  • Simulating the lateral performance of FRP-confined RC circular columns
           using a new eccentric-based stress-strain model
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): Ahmed M. Ismail, Mohamed F.M. Fahmy, Zhishen Wu
      In this study, a stress-strain model of fiber-reinforced polymers (FRPs)-confined concrete based on the lateral confinement stiffness was adopted to simulate the lateral response of RC columns retrofitted with external FRP jackets and tested under axial and lateral loads. The adopted model and other five-stress-strain models (established in former studies) were comparatively studied to simulate the seismic response of eight RC-circular columns retrofitted with FRP jackets and experimentally tested under both axial and lateral loads. Compared to the experimental results, the simulation results indicated that all stress-strain models could not identify properly the ultimate lateral displacements of the simulated columns. The adopted stress-strain model was revised to consider the effect of a key influential parameter (eccentricity ratio), which showed a critical impact on the simulation of the seismic response of RC-columns under combined bending and axial loadings. Finally, the proposed model was evaluated in predicting the lateral response of additional three columns and the simulation results exhibited a good agreement with the experimental results.

      PubDate: 2017-09-02T15:56:38Z
  • On the application of viscoelastic orthotropic double-nanoplates systems
           as nanoscale mass-sensors via the generalized Hooke’s law for
           viscoelastic materials and Eringen’s nonlocal elasticity theory
    • Abstract: Publication date: 15 November 2017
      Source:Composite Structures, Volume 180
      Author(s): K. Rajabi, Sh. Hosseini-Hashemi
      Reviewing the literature reveals that in all previous research works related to the damped vibration analysis of nanoplates, the material damping of nanoplates has been represented by Kelvin-Voigt model without any reasonable justification. The Kelvin-Voigt model has no instantaneous elasticity in creep and also shows unrealistic behavior in relaxation. Due to these drawbacks, the Kelvin-Voigt model fails to capture time domain characteristics of viscoelastic solid materials correctly. On the other hand, the Zener model can predict both creep and relaxation functions of a viscoelastic solid material well in the time domain. The generalized Hooke’s law for viscoelastic materials (GHLVMs) bridges the differential form of linear viscoelasticity and the integral form of linear viscoelasticity. In the present study based on the combination of GHLVMs and the nonlocal elasticity theory, a general 2-D theory of nonlocal viscoelasticity is obtained. A nanoscale mass-sensor is proposed based on the damped frequency analysis of a viscoelastic orthotropic double-nanoplates system (VODNS). The material damping of the nanoplates is represented by the Zener model. It has been assumed that the nanoplates obey the Kirchhoff-Love plate hypotheses. Detailed parametric study is presented.

      PubDate: 2017-09-02T15:56:38Z
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