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  Subjects -> ENGINEERING (Total: 2266 journals)
    - CHEMICAL ENGINEERING (190 journals)
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    - ENGINEERING (1195 journals)
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ENGINEERING (1195 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (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: 216)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 1)
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: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 4)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 6)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
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: 9)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
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: 13)
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: 35)
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: 5)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 6)
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 Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 4)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 2)
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: 7)
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: 7)
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: 3)
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: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
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     Full-text available via subscription   (Followers: 13)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 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: 4)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 2)
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: 23)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 252)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 177)
Composites Part B : Engineering     Hybrid Journal   (Followers: 223)
Composites Science and Technology     Hybrid Journal   (Followers: 164)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
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: 25)
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: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
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: 7)
Control Engineering Practice     Hybrid Journal   (Followers: 40)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 | Last

Journal Cover Composite Structures
  [SJR: 2.408]   [H-I: 92]   [252 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0263-8223
   Published by Elsevier Homepage  [3032 journals]
  • Corrigendum to “Prediction of yield strength of MWCNT/PP nanocomposite
           considering the interphase and agglomeration” [Compos. Struct. 168
           (2017) 657–662]
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): K.I. Tserpes, A. Chanteli, I.S. Floros


      PubDate: 2017-04-25T11:07:44Z
       
  • Surface effects on resonance frequencies of axially functionally graded
           Timoshenko nanocantilevers with attached nanoparticle
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): D.Q. Chen, D.L. Sun, X.F. Li
      Free vibration analysis of functionally graded nanocantilevers carrying a nanoparticle is made. Due to nanoscale beams, the Timoshenko beam theory incorporating surface effects is used. An emphasis is placed on the effect of the mass and rotational inertia of the nanoparticle and the gradient index on the resonance frequencies for nanowires made of functionally graded materials. The initial value method of a system of ordinary differential equations is developed to determine the resonance frequencies. The resonance frequencies of functionally graded nanocantilevers with attached mass are calculated for various indices. The method’s effectiveness is verified by comparing our results with previous ones for special cases. Numerical results shed light on the influences of the surface effects, attached mass and its rotational inertia, and gradient index on the resonance frequencies.

      PubDate: 2017-04-25T11:07:44Z
       
  • Delamination detection in carbon fiber reinforced plastic cross-ply
           laminates using crack swarm inspection: Experimental verification
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Ryosuke Matsuzaki, Kentaro Yamamoto, Akira Todoroki
      In the present paper, we investigated the experimental effectiveness of crack swarm inspection for delamination detection in cross-ply CFRP laminates. Electrodes of the test piece on the surface were made of silver paste, and electric potential changes before and after the damage were measured as true value data by the LCR meter. We also investigated the influence of electrode interval on estimation accuracy by changing the width and the number of the electrodes installed on the test piece surface. As a result, it was confirmed that even in the case where the electrode interval is long, the delamination can be detected within the error range of 10mm in the location estimation. In addition, the accuracy of the length estimation became particularly high by shortening the electrode interval, and in the case of electrode interval of 4.5mm, it was possible to detect within the error range of approximately 5mm even in length estimation.

      PubDate: 2017-04-25T11:07:44Z
       
  • Buckling of composite cylindrical shells with rigid end disks under
           hydrostatic pressure
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): A.V. Lopatin, E.V. Morozov
      An analytical solution of the buckling problem formulated for a composite cylindrical shell with its ends closed by rigid disks and subjected to hydrostatic pressure is presented in the paper. The problem is solved using Fourier decomposition and the Galerkin method. The boundary conditions are assigned in the form accounting for axial displacements of the end disks caused by an axial contraction of the deformed shell. The hoop displacement and deflection of the shell are approximated by the beam function corresponding to the first mode shape of vibration of a clamped-clamped beam. The axial displacement is approximated by the third derivative of the beam function. Based on this solution, a number of analytical formulas enabling calculations of critical hydrostatic pressure for composite orthotropic cylindrical shells are derived. Using these formulas, the critical loads are calculated for the shells with various elastic and geometric properties. The calculations are verified by comparisons with the results of finite-element analyses. The efficiency of analytical solutions in the search for fibre reinforcement arrangements providing maximum resistance to buckling is demonstrated by several examples.

      PubDate: 2017-04-25T11:07:44Z
       
  • Evaluation of bond properties of degraded CFRP-strengthened double strap
           joints
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Chamila Batuwitage, Sabrina Fawzia, David Thambiratnam, Riadh Al-Mahaidi
      The application of CFRP has become a popular strengthening technique for retrofitting of metallic structures. However, knowledge is very limited on the durability of CFRP composites under different environmental conditions. This paper presents the outcomes of a research program on the bond characteristics and environmental durability of degraded CFRP-strengthened steel plate double strap joints. Investigations were carried out on failure mode, ultimate load, joint strength, effective bond length and the effect of embedded GFRP layers for double strap joints. Shear stress-slip curves were developed for degraded CFRP-steel composite using the experimentally measured strain data. Results show that the failure modes and joint capacities are highly dependent on the number of CFRP layers utilised in the composite systems under environmental conditioning. The use of embedded GFRP layers can improve the long-term durability of the composite system. However, optimum structural properties could not be achieved using embedded GFRP as the innermost layer. The bond-slip responses for degraded CFRP double strap joints were shown to have an approximately bilinear relationship.

      PubDate: 2017-04-25T11:07:44Z
       
  • Comparative assessment of support plates’ influences on delamination
           damage in micro-drilling of CFRP laminates
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): A. Dogrusadik, A. Kentli
      In this study, drilling induced delamination damage which occurs during micro-drilling of CFRP laminates was investigated experimentally under variable cutting speeds and feed rates. Unlike the previous studies, the delamination factors in micro-drilling of CFRP laminates were precisely calculated and compared for supported and unsupported cases. Using support plates which are placed front and rear sides of the CFRP laminate is one of the methods which limits the delamination damage. Two different setups of support plates were used in the experiments. In the first setup, the entry board was aluminum plate and the backing board was phenolic plate. In the second setup, the entry board was brass plate and the backing board was wooden plate. Hole pictures were taken from each CFRP laminate by using a digital microscope. The first, the middle and the last three holes were inspected from the front and rear sides of the CFRP laminate. Minitab was used to evaluate the experiments’ outputs, and response surface method was used to optimize the process parameters. It has been revealed that the delamination damage in micro-drilling differs from the delamination damage in conventional drilling of CFRP laminates. Obviously, the process exhibits unusual delamination behavior as process size decreases.

      PubDate: 2017-04-25T11:07:44Z
       
  • Effect of bond on flexure of concrete beams prestressed with FRP tendons
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Tiejiong Lou, Muyu Liu, Sergio M.R. Lopes, Adelino V. Lopes
      The objective of this study is to reveal the effect of bond between composite tendons and concrete on the short-term behavior of fiber reinforced polymer (FRP) prestressed concrete beams. Based on a nonlinear model that has been calibrated by experimental data, numerical tests are performed on both simply supported and continuous beams prestressed with bonded and unbonded FRP tendons. Various levels of prestressing reinforcement ratio (ρp ) are used. The analysis shows that the bond condition of FRP tendons has a remarkable influence on the flexural response of FRP prestressed concrete beams, including failure mode, crack pattern, deformation, increase in tendon stress and neutral axis movement. Moment redistribution by unbonded FRP tendons is obviously higher than that by bonded ones at a low ρp level, but the redistribution discrepancy appears to be insignificant at a high ρp level. ACI 318-11 can satisfactorily reflect the bond effect on moment redistribution in FRP prestressed concrete continuous beams but CSA A23.3-04 cannot.

      PubDate: 2017-04-25T11:07:44Z
       
  • Shear strength of reinforced concrete beams strengthened in shear using
           externally-bonded FRP composites
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Deuck Hang Lee, Sun-Jin Han, Kang Su Kim, James M. LaFave
      A shear strength estimation model for reinforced concrete (RC) beams, the so-called dual potential capacity model (DPCM), has previously been proposed by the authors. In this study, the DPCM is extended to estimate the shear strength of RC beams strengthened in shear by using externally-bonded fiber-reinforced polymer (FRP) composites. The proposed model has been derived so as to take into account the effects of the type of FRP composite, fiber-bonding configuration, and fiber layout, and it can also determine the critical shear failure modes of RC beams strengthened by externally-bonded FRP composites. To verify the accuracy of the proposed model, shear test results of 227 RC beams strengthened by externally-bonded FRP composites were collected from previous studies, and it is shown that the analysis results estimated by the DPCM agree well with those test results.

      PubDate: 2017-04-25T11:07:44Z
       
  • Effective calibration and validation of a nonlocal continuum damage model
           for laminated composites
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): N. Zobeiry, A. Forghani, C. McGregor, S. McClennan, R. Vaziri, A. Poursartip
      A combined experimental and numerical approach is presented to calibrate the parameters of a previously developed nonlocal damage model used to simulate the inelastic response of laminated composites within a macroscopic modelling framework. In this approach, a limited number of physically-based damage parameters are obtained by conducting tests on notched specimens while employing the Digital Image Correlation (DIC) technique. These parameters are then used to calibrate a non-local sub-laminate based damage mechanics model, CODAM2. Compared to available ply-based approaches; the sub-laminate damage model reduces the computational time significantly while capturing the overall damage behaviour of the laminate. The damage model is implemented as a built-in material model in the commercial finite element code, LS-DYNA (MAT_219) and also in the open-source object oriented finite element code, OOFEM. To validate this approach, experiments were conducted on notched tensile specimens with varying notch-tip radii that result in a range of behaviour from stable to unstable damage growth as this radius increases. The calibrated damage model was used to predict this transition.

      PubDate: 2017-04-25T11:07:44Z
       
  • Multi-objective optimisation in vibration-assisted drilling of CFRP/Al
           stacks
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Chunliang Kuo, Zhihao Li, Chihying Wang
      In this work, carbon fibre reinforced plastic (CFRP) laminate and aluminium (Al7075T6) plates were bonded before undergoing single shot drilling on a vibration platform. The proposed vibration-assisted drilling in the electromechanical-driven system interacting with the cutting condition was shown to achieve outstanding results with regard to material removal, tool wear, hole quality and surface integrity. The statistical significance of individual operating parameters was determined using a main effects plot in conjunction with ANOVA. Multi-objective optimisation in MATLAB coding led to the following optimal combination of operating parameters: cutting speed (148/200m/min), feed rate (0.08mm/rev), and vibration frequency (55Hz) with amplitude (0.005mm). Surface roughness (CFRP: Ra 0.651µm, Al: Ra 0.436µm) was shown to have the least effect on the other seven performance criteria. Equal weighting amongst all objectives was sufficient to improve the overall accuracy (91.96%) in the optimisation. This multi-objective approach largely overcomes the single-objective limitations inherent in the conventional Taguchi method.

      PubDate: 2017-04-25T11:07:44Z
       
  • Thermal analysis of thin-walled deployable composite boom in simulated
           space environment
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): J.B. Bai, R.A. Shenoi, J.J. Xiong
      This paper seeks to investigate thermal behaviour of a thin-walled deployable composite boom (DCB) in a space environment using ground thermal-vacuum test and FEA methods. Thermal tests simulating a space environment include three key conditions, namely ultra-high level of vacuum (lower than 10−5 Pa), heat sink (−180°C) that is realized using black panels with the liquid-nitrogen cooling system and thermal loading that is achieved through infrared lamps. The thermal tests of the DCB under seven typical heat fluxes were conducted to characterize heat transfer mechanisms and to obtain temperature fields. The basic heat transfer methods for the DCB in a space environment were surface radiation, cavity radiation and heat conduction. These led to significant temperature difference and gradient occurring on the irradiated and shadowed parts of the DCB at nighttime and daytime. FE models were established to predict temperature fields and thermally induced deformation. Good correlation was achieved between experimental and numerical results.

      PubDate: 2017-04-25T11:07:44Z
       
  • Finite element modeling of damage development in cross-ply composite
           laminates subjected to low velocity impact
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Chao Zhang, Enock A. Duodu, Jinan Gu
      Composite laminates are susceptible to low-velocity impact and the induced damage substantially reduces the residual mechanical performance and safe-service life of the composite structures. In this paper, a finite element model based on continuum damage mechanics is presented to study the dynamic mechanical response and damage development in cross-ply composite laminates subjected to transverse low velocity impact. Hashin criterion and a gradual degradation scheme are applied to predict the intra-laminar damage initiation and evolution; a damage-friction interface constitutive model is utilized to predict the inter-laminar delamination induced by impact loading. A user-material subroutine VUMAT involving these constitutive models of intra-laminar and delamination damage is coded and implemented in the finite element package ABAQUS/Explicit. Numerical analysis is conducted on cross-ply composite specimens with different impact energies to study the impact force-time, force-displacement and energy-time histories curves as well as the damage evolution behaviors of matrix cracking and interface delamination. The numerical results show acceptable accord with available experimental data validating the efficiency of the proposed model. Moreover, the effect of interface friction on the delamination inhibition response of cross-ply composite laminates under impact is also investigated.

      PubDate: 2017-04-25T11:07:44Z
       
  • Passive control of damaged composite laminates with optimized location of
           piezoelectric fiber composite patches
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): V.M. Sreehari, D.K. Maiti
      This work presents a novel technique to enhance the bending, buckling, and post buckling characteristics of a damaged composite plate. This technique uses piezoelectric fiber composite patches (PFCP) for enhancing the performance and thereby reducing the effects of internal flaws. This paper discusses about the employment of PFCPs in their optimized location. Unified particle swarm optimization (UPSO) is employed for optimizing the PFCP locations for maximum critical buckling temperatures. An inverse hyperbolic shear deformation theory is used for advanced accuracy of the analysis of the smart plate. The post buckling behavior is studied with varying the number of optimally located PFCPs using modified Newton Raphson method. The obtained results are matched with those in the existing literature, wherever possible. It is observed that this is a very promising means of designing new smart material applications.

      PubDate: 2017-04-25T11:07:44Z
       
  • Sandwich panels with layered graded aluminum honeycomb cores under blast
           loading
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Shiqiang Li, Xin Li, Zhihua Wang, Guiying Wu, Guoxing Lu, Longmao Zhao
      Sandwich panels with triple layered graded honeycomb cores were tested under blast loading. The structural response was analyzed by using finite element software LS-DYNA after validation against the experiments. The structural deformation modes were classified into three types and the core layer deformation was divided into three regions. For the same value of impulse, a localized impulse led to severely localized deformation mode. A relatively evenly distributed impulse resulted in largely global bending deformation. Under the same loading, graded panels with the core of the largest relative density placed near the impact face suffered a smaller deflection than the panels with uniform core. Furthermore, for the same deformation mode the normalized back face sheet deflection increased linearly with impulse.

      PubDate: 2017-04-25T11:07:44Z
       
  • Improvement of joinability in a hole clinching process with aluminum alloy
           and carbon fiber reinforced plastic using a spring die
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Chan-Joo Lee, Byung-Min Kim, Beom-Soo Kang, Woo-Jin Song, Dae-Cheol Ko
      Hole clinching is a method for joining carbon fiber reinforced plastic (CFRP) and ductile materials. Previously, in conventional hole clinching, the joinability of CFRP and ductile materials was limited by the ductility of deformed materials, and damages to CFRP laminates. In this study, a new type of hole clinching tool called a spring die is proposed. This tool is designed to improve the joinability of materials in a hole clinching process using CFRP and aluminum alloy (AA5083). In spring die hole clinching, two pads supported by a coil spring are employed to improve the formability of ductile materials and to reduce damages to CFRP laminates by increasing the compressive hydrostatic stress during the hole clinching process. The effects of compressive hydrostatic stress on joinability in the hole clinching process were evaluated by FE-analysis and experiments. Finally, a single lap shear test was carried out to verify the applicability of hole clinching for joining CFRP and aluminum alloy.

      PubDate: 2017-04-18T11:02:29Z
       
  • Influence of the coupling matrix B on the interactive buckling of FML-FGM
           columns with closed cross-sections under axial compression
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Zbigniew Kolakowski, Radoslaw J. Mania
      The study of the coupled instabilities of thin-walled columns with trapezoidal and square cross-sections, which are made of Functionally Graded Materials (FGMs) and Fibre Metal Laminates (FMLs) is presented in the paper. It is assumed that each column wall is made of a stack of nine FML layers and/or a single FGM (Al-TiC) and/or ceramics (TiC). The GLARE 3 type FML part was made of an alternate sequence of Al 2024-T3 and even GFR prepreg layers where aluminium was always the outer layer. In the case of the FGM layer, volume fractions of ceramics and the metal distribution throughout the layer thickness are described by a simple power law. It is assumed that the columns are subjected to axial compression and simple supported at their loaded edges. All constituent materials obey Hooke’s law. The effect of temperature influence is neglected. To determined governing equations of considered FML-FGM structures the classical laminate plate theory (CLPT) is used. The solution to the problem of the non-linear buckling of hybrid thin-walled structure is based on the Koiter’s theory. An interaction of the global buckling mode with two local buckling modes is taken into account. In order to derive the equilibrium equations of FML-FGM profiles, the full Green’s strain tensor and the second Piola-Kirchhoff’s stress tensor have been adapted. The presented solution seems to be especially important as the authors have not found no earlier studies on the coupled buckling of thin-walled FML-FGM structures with closed cross-sections.

      PubDate: 2017-04-18T11:02:29Z
       
  • Transversal crack and delamination of laminates using XFEM
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Nur Azam Abdullah, Jose Luis Curiel-Sosa, Zeike A. Taylor, Behrooz Tafazzolimoghaddam, J.L. Martinez Vicente, Chao Zhang
      This paper offers a new insight into the computational modelling of crack and delamination of carbon fiber composite. Both transversal cracks (intralaminar) and delamination (interlaminar) are modelled with Extended Finite Element Method (XFEM). Constitutive and fracture laws are integrated to model the initiation of crack or delamination, and their subsequent evolution. The study includes the size effect assessment of composite due to the increment of composite thickness. The results are in close agreement between the experimental and analytical data of each specimen modelled based on the size of the carbon fiber composite volume.

      PubDate: 2017-04-18T11:02:29Z
       
  • Threaded inserts pull-through behaviour in carbon-epoxy thick laminates
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Edoardo Maria Carrai, Alessia Prato, Marco Anghileri
      Aim of this work, is the experimental assessment of the mechanical behaviour of threaded inserts, commonly used in racing cars. Tests have been performed, both in tension and in torsion, as a function of the installation technique in composite materials. Different type of inserts have been considered to evaluate the influence of materials on the strength of the inserts. From results has been proved that the installation technique influences very little the pull through strength, whilst it mostly affects the torsion strength. In particular, the failure torque is heavily influenced whether a bonding adhesive is used or not during the insert installation. Numerical models have also been made to simulate the inserts pull-through, using the commercial code LS-Dyna®, an explicit finite element code especially used in crashworthy problems. Due to the thick composite structure, a thick shell numerical laminate has been modeled. The plies have been tied each other with a failure contact model. Numerical results show a good correlation with experimental data both in force-displacement curve and in material local damage.

      PubDate: 2017-04-18T11:02:29Z
       
  • Strength and fire resistance of a high-strength nano-polymer modified
           cementitious composite
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Su-Jin Lee, Se-Ho Kim, Jong-Pil Won
      This study evaluated the strength and fire resistance of a high-strength nano-polymer modified fireproof cementitious composite in which a part of the cement was replaced by chamotte, nanoclay and silica fume. To secure high strength and fire resistance, chamotte was substituted in the range of 10–30wt%, nanoclay in the range of 1–3wt%, and silica fume in the range of 5–10wt%, with respect to the unit weight of cement. A basic mixing test was conducted in accordance with each substitution variable and the compressive strength was statistically analysed. Based on this analysis, the replacement ratio of nanoclay was adjusted to 0.5–1wt% and that of silica fume to 5–7wt%. Statistical response surface analysis was used to identify candidate and optimal mixes. The initial (28-day) and residual (after exposure to high temperature) compressive strengths were measured for these mixes. The compressive strengths were also predicted from the response surface model. The highest measured value occurred when chamotte was substituted at 10–12wt%. The best balance of cost and physical properties was identified for the composition having substitution levels of 0.5wt% nanoclay and 5.6wt% silica fume.

      PubDate: 2017-04-18T11:02:29Z
       
  • Effects of z-pin’s porosity on shear properties of 2D C/SiC z-pinned
           joint
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Yi Zhang, Litong Zhang, Jiaxin Zhang, Xiaowei Yin, Chidong Liu
      In this paper, 2D C/SiC z-pinned joint is prepared via chemical vapor infiltration. Effects of z-pin’s porosity on shear properties of z-pinned joint are investigated from the failure mode and the shear damage mechanisms. The results show that the average joint shear strength decreases asymptotically from 249.9MPa to 97.2MPa as the total porosity of 2D C/SiC z-pin increases from 14.4% to 27.3%. For each porosity, the joint shear strength is between the tensile strength and the in-plane shear strength of 2D C/SiC, which is rationalized by the rigid body sliding model of 2D C/SiC. Because high porosity leads to large rotational deformation of transverse fibers, a critical porosity about 17.7% is observed from shear-controlled failure to bending-controlled failure. A cohesive fracture model is developed to build the relation between the joint shear strength and the mechanical properties of 2D C/SiC. Very good accuracy is obtained.

      PubDate: 2017-04-18T11:02:29Z
       
  • Mechanical and thermal properties of carbon foam derived from phenolic
           foam reinforced with composite particles
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Seung A Song, Youngmin Lee, Yeon Su Kim, Seong Su Kim
      Carbon foams are fabricated by carbonization of polymer foams derived from phenolic resin. Phenolic resins are a good source of carbon or carbon composite materials due to their low level of toxic gas emission during pyrolysis and high heat resistance. However, carbon foams based on phenolic foams have inferior mechanical strength because of glassy carbon formed during the carbonization procedure. The reinforcement of phenolic foams with nano-particles improves the mechanical strength of the carbon foam due to high cell density and cell uniformity. However, aggregation of the nano-particles in the carbon foam can cause poor interfacial bonds and degrade the mechanical properties. Here, composite particles of exposed multi-walled carbon nanotubes in polyimide were used to improve the dispersion of the particles and increase the carbonization yield. In addition, the cell density and uniformity of the phenolic foam were clearly improved by the uniform dispersion of such composite particles in the phenolic resin. The carbon foams were fabricated via carbonization of the phenolic precursor foams at 1000˚C in a nitrogen atmosphere. The cell morphology was characterized by scanning electron microscopy and the foam density and cell density were measured. Mechanical and thermal properties of the foams fabricated under different conditions were characterized by compressive tests and the transient plane source method, respectively.

      PubDate: 2017-04-11T12:57:02Z
       
  • Three-dimensional modeling of the wave dynamics of tensegrity lattices
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): F. Fabbrocino, G. Carpentieri
      This paper develops effective numerical models to study the wave dynamics of highly nonlinear tensegrity metamaterials. Recent studies have highlighted the geometrically nonlinear response of structural lattices based on tensegrity prisms, which may gradually change their elastic response from stiffening to softening through the modification of mechanical, geometrical, and prestress variables. We here study the nonlinear dynamics of columns of tensegrity prisms subject to impulsive compressive loading. An effective nonlinear rigid body dynamics is employed to simulate the dynamic response of such metamaterials. We illustrate how to pass from the matrix to the vector form of the equations of motions, on accounting for a rigid response of the compressive members (bars). Numerical simulations show that the wave dynamics of the examined metamaterials supports compression solitary pulses with profile dependent on the elastic properties of the tensile members (strings), the given impact velocity, and the applied prestress. We conclude that tensegrity columns can be effectively used as tunable acoustic lenses, which are able to generate acoustic solitary waves with adjustable profile in a host medium.

      PubDate: 2017-04-11T12:57:02Z
       
  • Spring-in analysis of CFRP thin laminates: numerical and experimental
           results
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): C. Bellini, L. Sorrentino, W. Polini, A. Corrado
      During the cure process of CFRP laminates, some geometrical unconformities can arise, due to several thermomechanical and thermochemical phenomena that make residual stress rise. Among these unconformities, one of the most studied is the spring-in, that is the deviation of the flange-to-flange angle from the design value. In this work a numerical model suitable to determine the spring-in value was developed and verified. The proposed model considered both the thermo-chemical and thermo-mechanical phenomena that happen during the cure process. Then, the numerical model was used for calculating the spring-in angle of lots of different laminates in order to evaluate the influence of the thickness, the corner radius and the layup sequence on the laminate deformation. For evaluating the influence of the above mentioned parameter on the spring-in a full factorial plan was designed, and the FEM analysis allowed a saving of time, energy and material. It was found that only the layup sequence influenced the spring-in. Finally, a preliminary analysis stated the possibility to extend the proposed model also to other geometries, such as U-shaped laminates.

      PubDate: 2017-04-11T12:57:02Z
       
  • Mechanical behavior of punched holes produced on thin glass fiber
           reinforced plastic laminates
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Francesco Lambiase, Massimo Durante
      The present investigation deals with an experimental analysis of punching process of Glass Fiber Reinforced Plastics (GFRP) sheets. The process has the potential to dramatically reduce the cycle time; thus, it can be used for industrial applications where large numbers of holes are needed. However, the laminate damage represents the major concern for the employment of hole punching. Thus, a campaign of experimental tests was conducted on thin laminates with varying the punch-die clearance. In addition, drilled holes were performed in order to compare the quality and strength of the holes performed by drilling and punching processes. To assess the influence of the process parameters on the holes quality, mechanical characterization was performed by means of tensile test with central hole and bearing test. Moreover, morphological analysis was conducted to determine the quality of the punched hole and the extension of the delaminated region. According to the achieved results, the damage produced by punching process, especially when small clearances were used, is limited and comparable to that produced by drilling process.

      PubDate: 2017-04-11T12:57:02Z
       
  • Building implicit-surface-based composite porous architectures
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Nan Yang, Shoujun Wang, Lilan Gao, Yutao Men, Chunqiu Zhang
      We propose a simple but effective implicit-surface-based (ISB) method for constructing composite porous scaffolds (including gradient, hybrid, hierarchical, stochastic porous structures, or their combinations) based on a certain number of control elements (points, line segments, polylines, polygons, etc.) that are provided by users. Our method efficiently integrates spatial partitioning and substructure assignments in an easy manner. Users need not consider complex transitions between substructures during design, as these are naturally constructed. Also, our method can easily reconstruct native tissue structures based on micro-CT data. Here we successfully fabricated porous scaffolds with polymer as well as titanium using additive manufacturing (AM) techniques for ready use in tissue engineering.

      PubDate: 2017-04-11T12:57:02Z
       
  • Stochastic characterisation methodology for 3-D textiles based on
           micro-tomography
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): Andy Vanaerschot, Francesco Panerai, Alan Cassell, Stepan V. Lomov, Dirk Vandepitte, Nagi N. Mansour
      A recently developed framework to quantify variability of common textile reinforcements of unit cell size is extended to allow for a stochastic description of complex three-dimensional (3-D) textile architectures spanning multiple unit cells. The reinforcement geometry is characterised from synchrotron micro-tomography images in terms of centroid coordinates and tow cross-section. The statistical information includes an average trend, standard deviation and correlation information. A general representation of correlation information is proposed to account for the different tow correlations depending on the location inside the 3-D architecture. The methodology is applied to the characterisation of a 3-D carbon fabric considered for NASA’s Adaptive Deployable Entry Placement Technology (ADEPT) system. Determining geometrical variability in the weave is of importance during the process of setting design margins and risk analysis. Statistical analysis demonstrates strong dependency on the crossover positions for the average trends and correlation data, with a substantially higher variation for the Z-interconnecting tows.

      PubDate: 2017-04-11T12:57:02Z
       
  • Barley residue reinforced polymer mortars: Fracture mechanics approach
    • Abstract: Publication date: 1 August 2017
      Source:Composite Structures, Volume 173
      Author(s): J.M.L. Reis, E.M. Menezes
      This research work aims to experimentally evaluate the fracture mechanics of polymer mortars reinforced with barley residue from the brewing industry. Barley reinforced polymer mortar samples were manufactured from 1% to 10% of barley residue, in weight, as aggregate substitute. Then, the resin content was varied from 12% to 20% in 5% of barley residue polymer mortars. Fracture tests were performed aiming to compare the fracture energy, Gf , fracture toughness, through the stress intensity factor KIc , and the modulus of elasticity (E). The results showed an improvement in the fracture properties of polymer mortars until 5% of barley residue were used. Also, resin content of 18% produced the best energy balance and resistance to crack propagation results. Ductility was improved with the use of barley residue in the manufacturing process of polymer mortars.

      PubDate: 2017-04-11T12:57:02Z
       
  • Global-local analysis of laminated plates by node-dependent kinematic
           finite elements with variable ESL/LW capabilities
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): E. Zappino, G. Li, A. Pagani, E. Carrera
      This work presents a class of plate finite elements (FEs) formulated with node-dependent kinematics, which can be used to construct global-local models with high numerical efficiency. Taking advantage of Carrera Unified Formulation (CUF), plate theory kinematics can be individually defined on each FE node, realizing a variation of refinement levels within the in-plane domain of one element. When used in the bridging zone between a global model and a locally refined one, an efficient global-local model can be constructed. Elements with variable ESL/LW kinematics from node to node are developed and applied in the global-local analysis of laminated structures. This work includes numerical examples in which LW models with refined kinematics are employed in local regions while ESL models are adopted in the less critical area, and modeling domains are connected by transition zone composed of elements with node-dependent kinematics. The obtained results are compared with solutions from literature and 3D FE modeling. For laminated plates with local effects to be considered, the proposed plate models can reduce the computational costs significantly while guaranteeing numerical accuracy without using special global-local coupling methods.

      PubDate: 2017-04-11T12:57:02Z
       
  • High-resolution elastic analysis of thin-ply composite laminates
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Jihed Zghal, Amine Ammar, Francisco Chinesta, Christophe Binetruy, Emmanuelle Abisset-Chavanne
      Several studies showed that thin-plies composite laminates apparently exhibit higher strength than its counterpart using thicker plies. In this work, a high-resolution numerical discretization based on the use of in-plane-out-of-plane separated representations within the Proper Generalized Decomposition – PGD – framework is performed in different composites laminates for determining the effect of ply-thickness on the laminate stiffness. The results reveal that the global stiffness increases with the ply-thickness reduction. The analysis also reveals that this mechanical enhancement is due to structural effects and not to the mechanical confinement initially advanced.

      PubDate: 2017-04-11T12:57:02Z
       
  • Thermal performance of modular GFRP multicellular structures assembled
           with fire resistant panels
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Lei Zhang, Yu Bai, Wei Chen, Fa-xing Ding, Hai Fang
      Modular glass fibre reinforced polymer (GFRP) multicellular structures were formed using pultruded GFRP box sections incorporated between two GFRP flat panels by adhesive bonding. Three types of fire resistant panels, namely glass magnesium (GM) board, gypsum plaster (GP) board and lightweight calcium silicate (CS) board, were installed at the outer face of the lower GFRP flat panel using screws. The lower surfaces of the built-up specimens were then exposed to fire. The thermal responses of the GFRP multicellular specimens assembled with different fire resistant panels were measured and comparatively analysed, in association with the damage patterns observed. It was found that the fire resistant panels effectively mitigated the temperature progressions developed in the GFRP components, thereby improving the fire insulation performance of those structural assemblies. The GM board provided the best fire insulation performance, with the highest temperature at the outer face of the upper GFRP flat panel (the surface unexposed to fire) being less than 120°C after 90min of fire exposure. Further, the effects of cavities and end closure configurations of the multicellular assemblies on the heat transfer were evaluated and highlighted.

      PubDate: 2017-04-11T12:57:02Z
       
  • Size-dependent analysis of homogeneous and functionally graded microplates
           using IGA and a non-classical Kirchhoff plate theory
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Shuo Liu, Tiantang Yu, Tinh Quoc Bui, Shifeng Xia
      The paper presents an effective thin plate formulation based on isogeometric analysis (IGA) and a non-classical Kirchhoff plate theory to study static bending, free vibration, and buckling behaviors of homogeneous and functionally graded microplates. The small scale effects are captured using a non-classical Kirchhoff plate theory which is developed based on a modified couple stress theory. The requirement for C1-continuity in terms of the non-classical Kirchhoff plate theory is straightforwardly possessed with the aid of inherent high-order continuity of non-uniform rational B-spline (NURBS). Studies on convergence and comparison with reference solutions are demonstrated in order to show the effectiveness and accuracy of the proposed method. Numerical examples are presented to illustrate the effects of small scale on the mechanical response of homogeneous and functionally graded microplates. The results reveal that the small scale effects lead to a reduction of deflection and an increase in frequency and buckling loads because of an increase in plate stiffness, and more importantly the small scale effects are significant for the thin plates.

      PubDate: 2017-04-11T12:57:02Z
       
  • Shear deformation theory using logarithmic function for thick circular
           beams and analytical solution for bi-directional functionally graded
           circular beams
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Anup Pydah, R.C. Batra
      A shear deformation theory including a logarithmic function in the postulated expression for the circumferential displacement is developed for thick circular beams and is used to analytically solve static deformations of bi-directional functionally graded circular beams. The consideration of a logarithmic term is motivated by the displacement field in the analytical solution of the plane strain elasticity problem of a hollow circular cylindrical shell. The non-zero shear traction boundary conditions at the two major surfaces of the beam are a priori satisfied by the assumed displacement field. The material properties are assumed to vary according to exponential and power laws, respectively, in the tangential and the thickness directions. Parametric studies conducted for the variation of stresses and displacements indicate that material properties can be tailored to satisfy several structural constraints. For the bending of a sandwich beam with a bi-directionally graded core and homogeneous isotropic facesheets, it is found that the maximum interfacial bending stress, the peak interfacial shear stress and the maximum interfacial peeling stress can be reduced, respectively, by 20%, 44% and 42%.

      PubDate: 2017-04-11T12:57:02Z
       
  • Estimating laminated glass beam strength via stochastic Rigid Body-Spring
           Model
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Luigi Biolzi, Siro Casolo, Vito Diana, Carlo Alberto Sanjust
      A numerical investigation on the load carrying capacity of a laminated glass beam modelled as a material with a random strength distribution is presented. The strength values were distributed randomly within the beam by a Monte Carlo simulation, according to statistical distributions calibrated on experimental results obtained from literature. A preliminary computational analysis based on the weakest link in the chain-model was conducted to study the dependence of the beam estimated limit load on the adopted discretization. Then, after determining the optimal size of the mesh, the elastic-plastic problem has been solved by a Rigid Body-Spring Model (RBSM) discrete approach. Finally, the variability of the load capacity of the structural element is evaluated as a function of the statistics of the strength related to the size of the defects. One thousand simulations were performed to obtain statistically significant quantitative results.

      PubDate: 2017-04-11T12:57:02Z
       
  • Strong sampling surfaces formulation for laminated composite plates
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): G.M. Kulikov, S.V. Plotnikova
      The paper focuses on the application of the sampling surfaces (SaS) method to exact solutions of elasticity for laminated plates. The SaS method is based on choosing the arbitrary number of SaS parallel to the middle surface in order to introduce the displacements of these surfaces as basic plate unknowns. Such choice of unknowns with the use of the Lagrange polynomials in assumed approximations of displacements through the layer thicknesses leads to a compact laminated plate formulation. The feature of the proposed approach is that all SaS are located inside the layers at Chebyshev polynomial nodes. The use of outer surfaces and interfaces is avoided that makes possible to minimize uniformly the error due to the Lagrange interpolation. Therefore, the strong SaS formulation based on direct integration of the equilibrium equations of elasticity can be applied efficiently to the obtaining of 3D exact solutions for laminated plates.

      PubDate: 2017-04-11T12:57:02Z
       
  • A generic type of frequency-domain spectral element model for the dynamics
           of a laminated composite plate
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Ilwook Park, Usik Lee
      Various solution techniques have been developed in the last decades for accurate prediction of the dynamic responses of a laminated composite structure. The spectral element method (SEM) is well known as an exact solution method that provides extremely accurate dynamic responses even in the high-frequency region. In this study, we develop a spectral element model for a rectangular finite composite plate element. The present spectral element model is developed by modifying the boundary splitting method introduced in the previous studies of the authors. As a result, the four corner nodes of the rectangular finite composite plate element, which were inactive (fixed) in the previous studies, become active. Thus, the present spectral element model can be used as a generic type of finite element, which can be applied to any laminated composite plates with arbitrary boundary conditions. The accuracy and efficiency of the present spectral element model are evaluated by comparing its results with exact solutions and solutions using the commercial finite element analysis package, ANSYS. In addition, the vibration and wave characteristics are numerically investigated by varying the lay-ups of some examples of laminated composite plates with various geometries and boundary conditions.

      PubDate: 2017-04-11T12:57:02Z
       
  • Micromechanical modeling of thin composite and reinforced magnetoelectric
           plates – Effective elastic, piezoelectric and piezomagnetic coefficients
           
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): D.A. Hadjiloizi, A.L. Kalamkarov, G.C. Saha, K.G. Christoforidis, A.V. Georgiades
      A comprehensive asymptotic homogenization model for the analysis of composite and reinforced magnetoelectric plates is developed. The model culminates in a set of unit cell problems via which the relevant expressions for the effective coefficients are derived. The micromechanical and geometrical platform pertinent to the desired model is set up in this paper which also obtains the effective elastic, piezoelectric and piezomagnetic coefficients; the remaining properties, including product properties, are calculated in another work. Examples of structures that can be examined include diagonally- and triangularly-reinforced plates, hexagonal honeycomb sandwich plates and others. The developed model can be used to customize the effective properties of a reinforced plate to the requirements of a particular engineering application by changing some geometric, structural or material parameter of interest. It is shown that in the limiting case of a thin composite plate of uniform thickness whereby electrical conductivity is ignored and all pertinent quantities are time-averaged the presented model converges to the familiar classical plate model. Overall, this paper represents an important addition to the existing literature in terms of the complex geometries that can be designed and analyzed and at the same time constitutes an important refinement over previously published work.

      PubDate: 2017-04-11T12:57:02Z
       
  • The nonlocal and gradient theories for a large deformation of
           piezoelectric nanoplates
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Jan Sladek, Vladimir Sladek, Slavomir Hrcek, Ernian Pan
      The von Karman large deformations are considered in the Mindlin plate theory described by the nonlocal and gradient elasticity for piezoelectric nanoplates. It is shown that electric intensity vector can be expressed by mechanical quantities. The governing equations for bending moments, normal and shear stresses are derived from the variational principle. The finite element method is developed for considered governing equations. Differences of both theories are presented.

      PubDate: 2017-04-11T12:57:02Z
       
  • Influence of inclined holes on the impact strength of CFRP composites
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): R.A.M. Santos, P.N.B. Reis, F.G.A. Silva, M.F.S.F. de Moura
      The objective of this work is to study the effect of inclined holes on the impact strength of carbon-fibre reinforced composites. For this purpose, plates with vertical and inclined holes were tested under low velocity impact and the respective results were compared with control samples without hole. It was observed that inclined holes promote lower maximum loads and higher displacements, which can be justified by the damage mechanisms associated to stress concentration. In fact, the damage becomes asymmetric and increases with hole inclination, as a consequence of change of stress field profile. A complex damage mechanism based on interaction between matrix cracking and delamination was identified. A three-dimensional numerical model based on cohesive zone modelling was developed to deal with damage mechanism and influence of inclined holes. It was concluded that it is crucial to account for matrix cracking to achieve a good prediction of delaminated area. The experimental trends concerning hole inclination were well captured by the model.

      PubDate: 2017-04-11T12:57:02Z
       
  • Creep behavior of insulated concrete sandwich panels with fiber-reinforced
           polymer shear connectors
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Paul M. Hopkins, Thomas Norris, An Chen
      Insulated concrete sandwich panels have been widely used because of their advantages of light weight and energy efficiency. More recently, research has been conducted to study their applications as roof/floor panels, where long term creep behavior is an important design concern. This paper presents a combined experimental and analytical study on the creep behavior of insulated concrete sandwich panels under bending. Four concrete panels were tested for creep loading. One was a conventional solid reinforced concrete slab, which was used as a benchmark panel. The other three sandwich panels had top and bottom concrete wythes with various thicknesses and a 76mm (3″) insulation layer in the middle. The wythes were connected with FRP segmental shear connectors. There were also steel reinforcing bars in both longitudinal and transverse directions. The tests were conducted with a static load of approximately 13.3kN (3000lbs), which corresponded to the linear-elastic range of the panel’s load-deflection curve. The duration of the test ranged from 150days to 250days for different panels. It can be concluded that one sandwich panel showed better long-term deflection results than the solid panel. Equations from American Concrete Institute (ACI) Building code and Finite Element (FE) method were used to analyse the panels. Good correlations can be observed between the FE and test results.

      PubDate: 2017-04-11T12:57:02Z
       
  • Impact damage growth in carbon fibre aluminium laminates
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Jarosław Bieniaś, Patryk Jakubczak
      The paper presents an analysis of the response of fibre metal laminate based on aluminium and carbon fibre reinforced polymer to low-velocity impact. The comparison of the force–time dependencies with the actual effects of the indenter–laminate system (using high-speed cameras) contributed to the identification of the representative points and ranges that determine characteristic changes in the laminate structure in terms of damage and specific forms of its degradation. The authors proposed five damage states of aluminium-carbon laminate during low-velocity impact. The initial stages of the damage is associated with internal degradation and plastic deformation of the laminate until the impact resistance of the fibre metal laminates indicated by the authors. Matrix cracks, delaminations between composite layers with different orientation, as well as delaminations at the metal/composite interface are the characteristic damage modes. The catastrophic failure with cracking of the aluminium layers and composite materials and impactor penetration of the hybrid laminate are the next stages. Identifying damage initiation, propagation and its stages in live-time analysis of an aluminium-carbon laminate under impact may lead to making progress in this kind of laminates and understanding and interpretation of the impact phenomena.

      PubDate: 2017-04-11T12:57:02Z
       
  • Data assimilation for three-dimensional flow monitoring in non-flat
           composite structures during vacuum-assisted resin transfer molding: A
           numerical study
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Ryosuke Matsuzaki, Masaya Shiota
      This study set out to investigate the applicability of data assimilation to the monitoring of the flow of non-planar 3D shapes through the integration of visual observations with a stochastic numerical simulation of the resin flow in a vacuum-assisted resin-transfer molding process. First, we investigated the effect of the image resolution on the flow-monitoring estimation performance. By means of numerical experiments using images of various resolutions, we verified the applicable range of the image resolution in the proposed technique. Furthermore, the proposed technique was applied to 3D structures such as curved surfaces or ribbed structures. Using the visual observation values, the impregnation distances obtained from the image data were calculated in combination with the shape of the molding. The results confirmed that our proposed method is capable of successfully estimating the 3D impregnation behavior and permeability fields.
      Graphical abstract image

      PubDate: 2017-04-11T12:57:02Z
       
  • Effects of a defoamer on the compressive strength and tensile behavior of
           alkali-activated slag-based cementless composite reinforced by
           polyethylene fiber
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Yun Lee, Jeong-Il Choi, Hyeong-Ki Kim, Bang Yeon Lee
      The pore characteristic is a factor that influences on the mechanical properties of composites; the characteristic can be controlled by a defoamer. This paper presents an experimental study on the effect of a defoamer on the compressive strength and tensile behavior of alkali-activated slag-based cementless composite reinforced by polyethylene fiber. Three types of mixtures were made according to the amount of defoamer and the compressive strength, tensile behavior, density, and pore size distribution were measured. Test results show that the compressive strength and tensile behavior of the alkali-activated slag-based polyethylene fiber reinforced composite investigated in this study can be improved by including a small amount of defoamer in the composite.

      PubDate: 2017-04-11T12:57:02Z
       
  • Free vibration and buckling of foam-filled composite corrugated sandwich
           plates under thermal loading
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Bin Han, Ke-Ke Qin, Qian-Cheng Zhang, Qi Zhang, Tian Jian Lu, Bing-Heng Lu
      The free vibration and buckling behaviors of foam-filled composite corrugated sandwich plates under thermal loading are investigated theoretically. A refined shear deformation theory is extended incorporating two different combinations of hyperbolic and parabolic shear shape functions. Equivalent thermoelastic properties of the foam-filled corrugation are obtained using the method of homogenization based on the Gibbs free energy. Based on hyperbolic-polynomial variation of all displacements across the thickness of both face sheets and sandwich core, the shear plate theory accounts for both transverse shear and thickness stretching effects. The theoretical predictions are validated against existing results as well as finite element simulations. The effects of geometric and material parameters on natural frequency and critical temperature change for buckling are systematically investigated. The proposed theory is not only accurate but also simple in predicting the free vibration and thermal buckling responses of composite sandwich plates with foam-filled corrugated cores.

      PubDate: 2017-04-11T12:57:02Z
       
  • Extension and reduction of Donnell-Vlasov shell theory to hybrid
           anisotropic materials
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): S.W. Chung, S.G. Hong, G.S. Ju
      The laminated circular cylindrical shells are complicated to analyze and more complicated when anisotropic materials are used with different thickness and different material properties. Also computing the critical stresses under various boundary and loading conditions is exceptionally sensitive and therefore reasonable simplification of the governing equation is in demand for practical design purpose. This article first formulated a shell theory for hybrid anisotropic materials by use of asymptotic integration method, the results are same as classical Donnell-Vlasov theory of single layer isotropic material, then a simplified governing equation was developed by means of adopting a different length scale. The new simplified version can be very useful when multiple materials and thicknesses are designed for practical purpose. Comparison of two different shell bending theories is discussed. Also presented are proper choices of the governing equations for different loading conditions. The theories are extremely useful for the analysis and design of advanced space vehicles and pressure vessels featured cylindrical shells with laminated walls of various materials and thicknesses.

      PubDate: 2017-04-11T12:57:02Z
       
  • Predicting the effective properties of 3D needled carbon/carbon composites
           by a hierarchical scheme with a fiber-based representative unit cell
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Songhe Meng, Leying Song, Chenghai Xu, Wei Wang, Weihua Xie, Hua Jin
      This paper presents a fiber-based representative unit cell (fRUC) on the mesoscale to estimate the elastic constants of a three-dimensional (3D) needled carbon/carbon (C/C) composite through a hierarchical modeling scheme. The material variations due to needle-punching, including fiber dislocations, fiber distributions and matrix pockets, are precisely considered in the proposed fRUC model. A quarter-size mathematical model with a periodic boundary condition of a general mesh is established to perform the fRUC analysis by using interpolation functions. The predictive results from the fRUC are transitioned to a ply representative unit cell (pRUC) based on the developed analytical homogenization method. The proposed model agrees well with the experimental results, and the effects of microstructural parameters on the overall composite properties are discussed. The results allow great confidence in the reliable predictions of the effective properties and the damage and strength of 3D needled C/C composites.

      PubDate: 2017-04-11T12:57:02Z
       
  • A semi-continuum-based bending analysis for extreme-thin micro/nano-beams
           and new proposal for nonlocal differential constitution
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): J.P. Shen, C. Li
      A modified semi-continuum Euler beam model with relaxation phenomenon is developed and the bending deformation of extreme-thin beam with micro/nano-scale thickness is presented. The external loads including concentrated force and uniformly distributed loads are considered and different boundary constraints are analyzed. The explicit solutions of bending deflection are determined using the minimum potential energy principle. The appropriate normalizations of semi-continuum deflections are obtained by using the corresponding classical bending deflections. It is more reasonable than previous studies using the semi-continuum deflection with 1.0 relaxation coefficient as the normalized denominator. Different trends of bending deflections emerge and they are caused by different surface relaxation properties. The comparisons of semi-continuum, classical continuum and nonlocal continuum models show good agreement unless the thickness is too small. Further the trial function, the position of concentrated force and the equivalent Young’s modulus are discussed in detail. Relation between the equivalent Young’s modulus and thickness is developed via a relative simple approach. It is seen that the equivalent Young’s modulus may increase or decrease with increasing the thickness which is associated with some previous controversial ideas. Such surface physical phenomena correspond to two opposite nonlocal elasticity models and subsequently a new proposal for differential constitutive equation of nonlocal continuum theory is put forward. Additionally, a nonlinear semi-continuum model is proposed and the elastic carrying capacity is predicted. The nonlinear bending deflection of extreme-thin beam is analyzed accordingly.

      PubDate: 2017-04-11T12:57:02Z
       
  • Investigation of mechanical properties of tufted composites: Influence of
           tuft length through the thickness reinforcement
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): LingShan Liu, Peng Wang, Xavier Legrand, Damien Soulat
      In the aerospace, transport and energy industries, laminated composites are widely used to manufacture thicker and more complex composite pieces. Three-dimensional (3D) fabrics have been developed to replace the multilayered reinforcements in some applications to increase performance through the thickness. The present study is dedicated to improving the understanding of the mechanical performances of 3D composite pieces reinforced by tufting. The tufting process and the equipment configuration are described in detail in the present paper. A 3D reinforcement architecture is prepared by the tufting process with varied tuft length, and then resin transfer moulding technology is used to manufacture the composite samples. Tensile tests are carried out to characterise specifically the influence of the tuft length on the tensile performance of tufting threads through the thickness of composites. The tensile results and microscopic analysis on the cross section of the 3D specimens show that the tuft length strongly influences the mechanical properties of tufted composite. Therefore, control of the tuft length is necessary to optimise the tufting process and thus improve the mechanical performance of assembled thick reinforcements and composites.

      PubDate: 2017-04-11T12:57:02Z
       
  • Strain rate and temperature effect on mechanical properties and failure of
           3D needle-punched Carbon/Carbon composites under dynamic loading
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Dian-sen Li, Hong-Wei Duan, Wei Wang, Dong-yun Ge, Lei Jiang, Qian-qian Yao
      High-strain-rate compression experiments were performed on 3D needle-punched Carbon/Carbon composites at room and elevated temperatures with a Split Hopkinson Pressure Bar (SHPB) apparatus in the longitudinal and transverse direction. Macro-fracture and Scanning Electron Microscope (SEM) micrographs were examined to understand the failure mechanism. The results show composites are characterized as high-strain-rate and temperature sensitivity. With increasing the strain rate, dynamic properties increase significantly. Moreover, transverse properties are higher than longitudinal properties. With increasing the temperature (up to 300°C), longitudinal and transverse curves rise up, dynamic strength and modulus increase and failure strain decreases. The results also indicate composites take on more serious damage and clear shear failure mode with increasing the strain rate. Longitudinal failure behaves as matrix cracking and compression process on fiber layers. While needle-punched fibers shear fracture and 0°/90° fiber layers delaminating dominate transverse impact failure. In addition, at high strain rates, brittle failure feature becomes more obvious with increasing the temperature.

      PubDate: 2017-04-11T12:57:02Z
       
  • Torsional vibration of bi-directional functionally graded nanotubes based
           on nonlocal elasticity theory
    • Abstract: Publication date: 15 July 2017
      Source:Composite Structures, Volume 172
      Author(s): Li Li, Yujin Hu
      The equation of torsional motion is presented in this paper to investigate the free torsional vibration behaviors of tubes made of a bi-directional functionally graded (FG) material, which is composed of two different materials with continuously varying along the radius and length directions. To incorporate the size effect of long-range forces, the nonlocal elasticity theory is employed to derive the difference equation of torsional motion, which can be reduced to the classical governing equation by simply setting a zero nonlocal parameter. Suppose that the effective material properties of the nanotube vary in the length direction according to an exponential distribute function and in the radius direction according to a power-law function. The closed-form solutions of torsional frequencies and mode shapes are derived. It is shown that the torsional frequencies can be significantly affected by the through-radius and through-length gradings of the bi-directional FG nanotubes and hence can be prescribed by tailoring the bi-directional nano-structures of the FG material. The torsional frequencies can be increased with the decreasing nonlocal parameter, whereas the size-dependent behaviors on the mode shape cannot be observed.

      PubDate: 2017-04-11T12:57:02Z
       
 
 
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