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  Subjects -> PHYSICS (Total: 736 journals)
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PHYSICS (623 journals)            First | 1 2 3 4 5 6 7 | Last

Computational Mathematics and Mathematical Physics     Hybrid Journal   (2 followers)
Computational Science and Discovery     Full-text available via subscription  
Computer Physics Communications     Hybrid Journal  
Contemporary Concepts of Condensed Matter Science     Full-text available via subscription  
Contemporary Physics     Hybrid Journal   (8 followers)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (3 followers)
Contributions to Plasma Physics     Hybrid Journal   (2 followers)
COSPAR Colloquia Series     Full-text available via subscription  
Cryogenics     Hybrid Journal   (11 followers)
Current Applied Physics     Full-text available via subscription   (4 followers)
Diamond and Related Materials     Hybrid Journal   (12 followers)
Differential Equations and Nonlinear Mechanics     Open Access   (4 followers)
Doklady Physics     Hybrid Journal   (2 followers)
Dynamical Properties of Solids     Full-text available via subscription  
ECS Journal of Solid State Science and Technology     Full-text available via subscription  
Egyptian Journal of Remote Sensing and Space Science     Open Access   (4 followers)
Embedded Systems Letters, IEEE     Hybrid Journal   (14 followers)
Energy Procedia     Open Access   (2 followers)
Engineering Failure Analysis     Hybrid Journal   (21 followers)
Engineering Fracture Mechanics     Hybrid Journal   (14 followers)
Environmental Fluid Mechanics     Hybrid Journal   (2 followers)
EPJ Nonlinear Biomedical Physics     Open Access  
EPJ Photovoltaics     Open Access  
EPJ Web of Conferences     Open Access  
European Journal of Mechanics - A/Solids     Hybrid Journal   (2 followers)
European Journal of Mechanics - B/Fluids     Hybrid Journal  
European Journal of Physics     Full-text available via subscription   (5 followers)
European Journal of Physics Education     Open Access   (5 followers)
European Physical Journal - Applied Physics     Full-text available via subscription   (4 followers)
European Physical Journal C     Hybrid Journal  
Europhysics News     Open Access   (1 follower)
Experimental Heat Transfer     Hybrid Journal   (5 followers)
Experimental Mechanics     Hybrid Journal   (15 followers)
Experimental Methods in the Physical Sciences     Full-text available via subscription  
Experimental Techniques     Hybrid Journal   (15 followers)
Exploration Geophysics     Hybrid Journal   (2 followers)
Few-Body Systems     Hybrid Journal  
Fire and Materials     Hybrid Journal   (4 followers)
Flexible Services and Manufacturing Journal     Hybrid Journal   (3 followers)
Fluctuation and Noise Letters     Hybrid Journal   (1 follower)
Fluid Dynamics     Hybrid Journal   (5 followers)
Fluid-Structure Interactions     Full-text available via subscription  
Fortschritte der Physik/Progress of Physics     Hybrid Journal  
Frontiers in Physics     Open Access   (2 followers)
Frontiers of Materials Science     Hybrid Journal   (4 followers)
Frontiers of Physics     Hybrid Journal   (1 follower)
Fusion Engineering and Design     Hybrid Journal   (2 followers)
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (21 followers)
Geografiska Annaler, Series A: Physical Geography     Hybrid Journal   (3 followers)
Geophysical Research Letters     Full-text available via subscription   (41 followers)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (19 followers)
Glass Physics and Chemistry     Hybrid Journal   (1 follower)
Granular Matter     Hybrid Journal   (2 followers)
Graphs and Combinatorics     Hybrid Journal   (4 followers)
Handbook of Geophysical Exploration: Seismic Exploration     Full-text available via subscription  
Handbook of Metal Physics     Full-text available via subscription  
Handbook of Surface Science     Full-text available via subscription   (2 followers)
Handbook of Thermal Analysis and Calorimetry     Full-text available via subscription  
Handbook of Thermal Conductivity     Full-text available via subscription   (1 follower)
Haptics, IEEE Transactions on     Hybrid Journal   (4 followers)
Heat and Mass Transfer     Hybrid Journal   (11 followers)
Heat Transfer - Asian Research     Hybrid Journal   (5 followers)
High Energy Density Physics     Hybrid Journal   (1 follower)
High Pressure Research: An International Journal     Hybrid Journal   (1 follower)
High Temperature     Hybrid Journal  
Hyperfine Interactions     Hybrid Journal   (2 followers)
IEEE Electromagnetic Compatibility Magazine     Full-text available via subscription   (2 followers)
IEEE Journal of Quantum Electronics     Hybrid Journal   (12 followers)
IEEE Photonics Technology Letters     Hybrid Journal   (3 followers)
IEEE Signal Processing Magazine     Full-text available via subscription   (21 followers)
IEEE Transactions on Electromagnetic Capability     Hybrid Journal   (10 followers)
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control     Hybrid Journal   (4 followers)
IET Optoelectronics     Hybrid Journal   (1 follower)
Il Colle di Galileo     Open Access  
Imaging Science Journal, The     Hybrid Journal   (2 followers)
Indian Journal of Biochemistry and Biophysics (IJBB)     Open Access   (4 followers)
Indian Journal of Physics     Hybrid Journal   (5 followers)
Indian Journal of Pure & Applied Physics (IJPAP)     Open Access   (8 followers)
Indian Journal of Radio & Space Physics (IJRSP)     Open Access   (4 followers)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (9 followers)
Industry Applications, IEEE Transactions on     Hybrid Journal   (5 followers)
Infinite Dimensional Analysis, Quantum Probability and Related Topics     Hybrid Journal  
InfraMatics     Open Access  
Infrared Physics & Technology     Hybrid Journal  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (1 follower)
Intermetallics     Hybrid Journal   (4 followers)
International Applied Mechanics     Hybrid Journal   (3 followers)
International Geophysics     Full-text available via subscription   (3 followers)
International Heat Treatment & Surface Engineering     Hybrid Journal   (2 followers)
International Journal for Computational Methods in Engineering Science and Mechanics     Hybrid Journal   (9 followers)
International Journal for Ion Mobility Spectrometry     Hybrid Journal   (1 follower)
International Journal for Simulation and Multidisciplinary Design Optimization     Full-text available via subscription   (1 follower)
International Journal of Abrasive Technology     Hybrid Journal   (2 followers)
International Journal of Aeroacoustics     Full-text available via subscription   (5 followers)
International Journal of Applied Electronics in Physics & Robotics     Open Access  
International Journal of Astronomy and Astrophysics     Open Access   (3 followers)
International Journal of Computational Fluid Dynamics     Hybrid Journal   (9 followers)
International Journal of Computational Materials Science and Surface Engineering     Hybrid Journal   (7 followers)
International Journal of Damage Mechanics     Hybrid Journal   (4 followers)
International Journal of Fatigue     Hybrid Journal   (5 followers)

  First | 1 2 3 4 5 6 7 | Last

European Journal of Mechanics - A/Solids    [4 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0997-7538
     Published by Elsevier Homepage  [2556 journals]   [SJR: 1.321]   [H-I: 48]
  • On the dynamic behaviour of masonry beam–columns: An analytical
           approach
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): Maria Girardi
      The paper presents an analytical approach to the study of the transverse vibrations of masonry beam–columns. Starting with the constitutive equation for beams made of a masonry–like material and the averaged Lagrangian of the system, some explicit approximate solutions are found to the problem of free damped periodic oscillations and forced oscillations in the case of primary resonance on the beam's first mode. In particular, a set of equations is obtained that gives the modulation over time of the system's energy and of the fundamental frequency of the beam's response. The analytical results are compared to those obtained via the finite element code NOSA–ITACA, developed at ISTI–CNR.


      PubDate: 2014-01-24T01:39:56Z
       
  • Prediction of the nonlocal scaling parameter for graphene sheet
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): Yingjing Liang , Qiang Han
      A nonlocal model considering the nonlocal stress as the weighted average stress, which incorporates information about small size scale, is presented. With this model, the explicit expression of the nonlocal scaling parameter is derived and the implication of the nonlocal scaling parameter is revealed. Moreover, exact closed form solutions for the nonlocal scaling parameter for zigzag and armchair graphene sheets are obtained and verified by molecular dynamics simulations. Nonlocal scaling parameter is not a constant but a scale-related variable dependent on the size of the structures and independent of the value of the loads.


      PubDate: 2014-01-24T01:39:56Z
       
  • Friction induced dynamics of ball joints: Instability and post bifurcation
           behavior
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): Cornelius Weiss , Michael M. Morlock , Norbert P. Hoffmann
      It is well known that ball joints may be subject to friction induced oscillations. In the present analysis the stability behavior of a ball joint model with Coulomb and Stribeck-type friction is studied and the post bifurcation behavior of the resulting limit cycles is determined. The bifurcating limit cycles can be followed for both types of friction, and velocity dependent friction is not necessary to yield vibrations, as was proposed in the literature before. The linear instability is found to be of the whirl or flutter type. The results suggest that, depending on the ball joint and friction parameters, a complicated variety of nonlinear periodic solutions exists. It is shown that the previously often used approach of computing parameter values where stable sliding turns unstable can not even serve as a first rough indicator for the existence of friction induced oscillations. Instead, existence areas for stable/unstable sliding and co-existing stable limit cycles give a far better impression of the system characteristics, and can even give hints on measures that can help to eliminate friction whirl vibrations from ball joints. The analysis yields that a low friction coefficient, low loads and high system or interface damping seem promising to calm squeaking joints, as is physically plausible. Furthermore, the combination of the momentary speed of rotation and the relative component kinematics has a huge impact on the existence of limit cycles – hence the human gait is likely to influence the occurrence of squeaking in total hip arthroplasty.


      PubDate: 2014-01-24T01:39:56Z
       
  • Static and free vibration analyses of small - scale functionally graded
           beams possessing a variable length scale parameter using different beam
           theories
    • Abstract: Publication date: Available online 18 January 2014
      Source:European Journal of Mechanics - A/Solids
      Author(s): Reza Aghazadeh , Ender Cigeroglu , Serkan Dag
      This article puts forward a modified couple stress theory based approach of analysis for small - scale functionally graded beams, that possess a variable length scale parameter. Presented procedures are capable of predicting static and dynamic beam responses according to three different beam theories, namely: Euler - Bernoulli beam theory, Timoshenko beam theory and third - order shear deformation beam theory. A variational method is used in conjunction with the modified couple stress theory to derive the governing partial differential equations. All properties of the small - scale functionally graded beams - including the length scale parameter - are assumed to be functions of the thickness coordinate in the derivations. The governing equations are solved numerically through the use of the differential quadrature method (DQM). Numerical results are generated for small - scale functionally graded beams, that comprise ceramic and metallic materials as constituent phases. Both small - scale beams subjected to static loading and those undergoing free vibrations are considered in the computations. Comparisons of the numerical results to those available in the literature point out that developed techniques lead to results of high accuracy. Further numerical results are provided, which demonstrate the responses of small - scale functionally graded beams estimated by the three different beam theories as well as provide insight into the influences of material parameters upon the static deflections and natural vibration frequencies.


      PubDate: 2014-01-20T01:36:29Z
       
  • On the generalized Barnett-Lothe tensors for anisotropic
           magnetoelectroelastic materials
    • Abstract: Publication date: Available online 17 January 2014
      Source:European Journal of Mechanics - A/Solids
      Author(s): Jun Lei , Chuanzeng Zhang
      The three generalized Barnett-Lothe tensors L, S and H are frequently encountered in the extended Stroh formalism of two-dimensional deformation of anisotropic magneto-electro-elastic materials. Meantime, they are directly related to the admittance matrix Y, which is required to characterize the crack-tip field. In this paper, the elements of L, S and H together with Y are constructed using a modified Lekhinitskii formalism for general anisotropic magneto-electro-elastic materials. As a typical case, the three generalized Barnett-Lothe tensors are explicitly expressed in terms of the reduced generalized elastic compliances for transversely isotropic magneto-electro-elastic materials. A simple example is presented to validate these expressions.


      PubDate: 2014-01-20T01:36:29Z
       
  • Nonlinear vibration analysis of Timoshenko nanobeams based on surface
           stress elasticity theory
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): R. Ansari , V. Mohammadi , M. Faghih Shojaei , R. Gholami , H. Rouhi
      In this article, the nonlinear free vibration behavior of Timoshenko nanobeams subject to different types of end conditions is investigated. The Gurtin–Murdoch continuum elasticity is incorporated into the Timoshenko beam theory in order to capture surface stress effects. The nonlinear governing equations and corresponding boundary conditions are derived using Hamilton's principle. A numerical approach is used to solve the problem in which the generalized differential quadrature method is applied to discretize the governing equations and boundary conditions. Then, a Galerkin-based method is numerically employed with the aim of reducing the set of partial differential governing equations into a set of time-dependent ordinary differential equations. Discretization on time domain is also done via periodic time differential operators that are defined on the basis of the derivatives of a periodic base function. The resulting nonlinear algebraic parameterized equations are finally solved by means of the pseudo arc-length continuation algorithm through treating the time period as a parameter. Numerical results are given to study the geometrical and surface properties on the nonlinear free vibration of nanobeams.


      PubDate: 2014-01-12T01:36:13Z
       
  • Parameter identification of a thermodynamic model for superelastic shape
           memory alloys using analytical calculation of the sensitivity matrix
    • Abstract: Publication date: Available online 7 January 2014
      Source:European Journal of Mechanics - A/Solids
      Author(s): F. Meraghni , Y. Chemisky , B. Piotrowski , R. Echchorfi , N. Bourgeois , E. Patoor
      This paper presents an identification procedure for the parameters of a thermodynamically based constitutive model for Shape memory Alloys (SMAs). The proposed approach is a gradient-based method and utilizes an analytical computation of the sensitivity matrix. For several loading cases, including superelasticity, that are commonly utilized for the model parameters identification of such a constitutive model, a closed-form of the total infinitesimal strain is derived. The partial derivatives of this state variable are developed to find the components of the sensitivity matrix. A Levenberg-Marquardt algorithm is utilized to solve the inverse problem and find the best set of model parameters for specific SMA materials. Moreover, a pre-identification method, based on the second derivative of the total strain components is proposed. This provides a suitable initial set of model parameters, which increases the efficiency of the inverse method. The proposed approach is applied for the simultaneous identification of the non-linear constitutive parameters for two superelastic SMAs. The comparison between experimental and numerical curves obtained for different temperatures shows the capabilities of the developed identification approach. The robustness and the efficiency of the developed approach are then experimentally validated.


      PubDate: 2014-01-08T01:36:28Z
       
  • On the angular velocity of a rigid body: Matrix and vector representations
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): J. Jesús Cervantes-Sánchez , José M. Rico-Martínez , Victor Hugo Pérez-Muñoz
      The angular velocity is an important property associated with the velocity state of moving rigid bodies. Unlike the velocity vector of a point, angular velocity vector is not in general equal to the time derivative of any single vector. Hence a unified, simple and comprehensible treatment of the subject may benefit the velocity analysis of complex multibody systems. This paper contributes with a new point of view of matrix and vector representations of angular velocity from the very foundations of classical kinematics of rigid bodies. This contribution was given a systematic, integrated and unified treatment, thus allowing the derivations to be based upon quantities which are expressed in terms of geometric objects (vectors) and geometric operations (vector addition, dot, and cross product). As a result, the approach leads naturally to simple and particularly useful expressions for the angular velocity vector, which allow a readily extension to three important representations involving the position and velocity of three noncollinear points pertaining to a moving rigid body.


      PubDate: 2014-01-04T01:34:50Z
       
  • An accurate semi-analytical method for an arbitrarily oriented edge or
           interior crack in an anisotropic homogeneous elastic solid
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): M.T. Kamali , H.M. Shodja
      In this work, a general semi-analytical method for the determination of the elastic fields within an anisotropic homogeneous elastic solid with an inclined edge or interior crack is developed. In this method, the displacement field is represented as a sum of a function and a finite series of functions with unknown coefficients. The functions are constructed in such a way that all the essential homogeneous and inhomogeneous boundary conditions are satisfied exactly and, moreover, the displacement discontinuity across the crack faces as well as the exact singular behaviour of the stress field at the crack-tip are captured. The unknown coefficients are determined by utilizing the principle of minimum potential energy; the obtained coefficients matrix involves some singular integrands which for their accurate integrations over the domain in the vicinity of the crack-tip the generalized Duffy transformation is employed. Following the calculations of the unknown coefficients, the displacement field and subsequently the remaining field quantities are obtained. The fracture parameters, stress intensity factor SIF and the crack opening displacement COD are readily evaluated. Comparisons of the solutions of several examples obtained by the current approach with the exact solutions reveal the efficacy of the proposed method.


      PubDate: 2014-01-04T01:34:50Z
       
  • Macroscopic modeling of functional fatigue in shape memory alloys
    • Abstract: Publication date: May–June 2014
      Source:European Journal of Mechanics - A/Solids, Volume 45
      Author(s): Noemi Barrera , Paolo Biscari , Marco Fabrizio Urbano
      We study a macroscopic homogenized model of shape memory alloys. Starting from the Souza-Auricchio model, we put forward some modifications fit to improve the capability of the model to predict and estimate the onset of functional fatigue in the material. More specifically, we consider the presence in the Helmholtz free-energy density of a macroscopic plastic term in order to represent the fact that microscopic plasticity involves macroscopic strains. We further introduce an evolution of the transformation domain, in order to represent the fact that the more plastic slips occur, the more limited is the phase space available for further microscopic phase transformations. We finally generalize the functional dependence of the rate of dissipation function in terms of the driving forces, in order to relax the previously introduced constraint that functional fatigue could arise if and only if microscopic phase transition occur. In this paper we discuss the constitutive consequence of the proposed modifications, we discuss the calibration of constitutive parameters by means of simple experiments, and evidence the qualitative agreement of the modeling predictions with the outcome of some reported experimental results.


      PubDate: 2013-12-27T10:37:22Z
       
  • Editorial board
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44




      PubDate: 2013-12-23T01:39:02Z
       
  • New laws for the tension/compression properties of Voronoi closed-cell
           polymer foams in relation to their microstructure
    • Abstract: Publication date: Available online 10 December 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): C. Barbier , P.M. Michaud , D. Baillis , J. Randrianalisoa , A. Combescure
      Closed-cell polymer foams are well-known for their thermal capabilities, but works on the mechanical behavior of these materials are scarce, especially concerning the influence of the foam’s microstructure. The objective of this study is to investigate the influence of the relative density and irregularity of Voronoi closed-cell foam structures on their elastic characteristics (such as the Young’s modulus and the Poisson’s ratio) and plastic characteristics (such as elastic limits and collapse stresses). New laws are proposed in order to approximate the macroscopic mechanical behavior of Voronoi closed-cell foams under uniaxial tension and compression.


      PubDate: 2013-12-11T09:02:30Z
       
  • Surface Wrinkles of Swelling Gels under Arbitrary Lateral Confinements
    • Abstract: Publication date: Available online 4 December 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Chen-Hsueh Yang , Yu-Yun Lin
      Based on perturbation analysis, this study investigates surface wrinkling of a gel layer under arbitrary lateral confinements in the equilibrium state of swelling. Gels containing incompressible polymer networks and solvents may incur large deformations and increase the volume by several times after swelling. Owing to the restrictions on lateral expansions and surface imperfections, the instabilities may appear in the form of wrinkling. Wrinkling is strongly governed by the compressibility of swollen gel, confinements and gel thickness. Additionally, gel compressibility is attributed to the migration of solvent under stress at the confined-swelling state, and can be expressed in terms of a confined-swelling volume ratio. This work also discusses possible gel-solvent systems of wrinkling under different confinements. At equal biaxial confinements, the wrinkle pattern is a combination of plane waves with the same wavelength in all directions. Meanwhile, at non-equal biaxial confinements, the wrinkle pattern may be a sum of plane waves with dissimilar wavelengths and corresponding directions.


      PubDate: 2013-12-07T01:39:12Z
       
  • Compressive brittle fracture in V-notches with end holes
    • Abstract: Publication date: Available online 4 December 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): A.R. Torabi , M.R. Ayatollahi
      The aim of this research was to present a brittle fracture model for predicting the compressive failure load of engineering components weakened by V-notches with end holes (VO-notches). For this purpose, two well-known brittle fracture models in tension, namely the point stress (PS) and the mean stress (MS) were applied to the compressive stress field around the VO-notches and for each model a closed-form expression was obtained for the compressive mode I notch fracture toughness. In order to evaluate the validity of PS and MS criteria, the theoretical values of compressive notch fracture toughness were compared with the experimental results reported recently in literature dealing with fracture in fine-grained isostatic graphite plates containing V-notches with end holes subjected to pure compression. The results showed that while the MS model with a total discrepancy of 5% was an appropriate failure criterion, the PS model with about 86% accuracy could not predict the experimental results satisfactorily.


      PubDate: 2013-12-07T01:39:12Z
       
  • A generalized nonlocal elasticity solution for the propagation of
           longitudinal stress waves in bars
    • Abstract: Publication date: Available online 1 December 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): U. Güven
      In the present work, the propagation of one dimensional wave along the axial direction of a nano scale bar is investigated using a unified nonlocal elasticity model with two parameters. The present analysis is mainly based on Love rod theory. However, the total elastic strain energy is calculated including the shear stress components by considering Bishop correction. Thus, by applying Hamilton’s principle, the explicit generalized nonlocal elasticity solution is obtained, and then, the comparative results of analysis are presented in detail.


      PubDate: 2013-12-03T01:38:59Z
       
  • Nonlinear axisymmetric response of FGM shallow spherical shells on elastic
           foundations under uniform external pressure and temperature
    • Abstract: Publication date: Available online 1 December 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Nguyen Dinh Duc , Anh Vu Thi Thuy , Pham Hong Cong
      Based on the classical shell theory taking into account geometrical nonlinearity, initial geometrical imperfection and Pasternak type elastic foundation, the nonlinear axisymmetric response of shallow spherical FGM shells under mechanical, thermal loads and different boundary conditions is considered in this paper. Using the Bubnov-Galerkin method and stress function, obtained results show effects of elastic foundations, external pressure, temperature, material and geometrical properties on the nonlinear buckling and postbuckling of the shells. The snap-through behaviors of the FGM spherical shallow shells on elastic foundations also are analyzed carefully in this paper. Some results were compared with the ones of other authors.


      PubDate: 2013-12-03T01:38:59Z
       
  • Capability of the BBC2008 yield criterion in predicting the earing profile
           in cup deep drawing simulations
    • Abstract: Publication date: Available online 25 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Marko Vrh , Miroslav Halilovič , Bojan Starman , Boris Štok , Dan-Sorin Comsa , Dorel Banabic
      The paper deals with constitutive modelling of highly anisotropic sheet metals and presents FEM based earing predictions in a round cup drawing simulation of highly anisotropic aluminium alloys where more than four ears occur. For that purpose the BBC2008 yield criterion, which is a plane-stress yield criterion formulated in the form of a finite series, is used. Thus defined criterion can be expanded to retain more or less terms, depending on the amount of given experimental data. To be used in sheet metal forming simulations the constitutive model, derived in accordance with the associated flow theory of plasticity, has been implemented in a general purpose finite element code ABAQUS/Explicit via VUMAT subroutine, considering alternatively different number of parameters in the BBC2008 yield criterion, where possible number of parameters are any multiple of number 8. For the integration of the constitutive model the explicit NICE (Next Increment Corrects Error) integration scheme has been used. The CPU time consumption for an explicit deep drawing simulation, which is based on the developed constitutive model, has been proven to be, due to effectiveness of the used integration scheme, fully comparable to the performance experienced when the simulation is performed with ABAQUS built-in constitutive models and implicit integration schemes. Two aluminium alloys, namely AA5042-H2 and AA2090-T3, have been considered for a validation of the constitutive model. The respective BBC2008 model parameters have been identified for both alloys with a developed numerical procedure, based on a minimization of the specified cost function. For both materials, the simulation predictions based on the BBC2008 model prove to be in very good agreement with the experimental results. Further, in order to show the flexibility of the BBC2008 model in modelling of highly anisotropic sheet metal response, we have introduced a highly anisotropic fictitious material which yields, according to the theory, twelve ears in cup drawing. As it is shown in the paper the BBC2008 model is able to predict twelve ears in cup drawing simulation with the formulation containing 16 parameters for anisotropy description only. The flexibility and accuracy of the constitutive model together with the robust identification and integration procedure guarantee the applicability of the BBC2008 yield criterion in industrial applications.


      PubDate: 2013-11-29T01:39:22Z
       
  • Discrete systems behave as nonlocal structural elements: Bending, buckling
           and vibration analysis
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): N. Challamel , C.M. Wang , I. Elishakoff
      It is shown herein that the bending, buckling and vibration problems of a microstructured beam can be modeled by Eringen's nonlocal elasticity model. The microstructured model is composed of rigid periodic elements elastically connected by rotational springs. It is shown that this discrete system is the finite difference formulation of a continuous problem, i.e. the Euler–Bernoulli beam problem. Starting from the discrete equations, a continualization method leads to the formulation of an Eringen's type nonlocal equivalent continuum. The sensitivity phenomenon of the apparent nonlocal length scale with respect to the bending, the vibrations and the buckling analyses is investigated in more detail. A unified length scale can be used for the microstructured-based model with both nonlocal constitutive law and nonlocal governing equations. The Finite Difference Method is used for studying the exact discrete problem and leads to tractable engineering formula. The bending behaviour of the microstructured cantilever beam does not reveal any scale effect in the presence of concentrated loads. This scale invariance is not a deficiency of Eringen's nonlocality because it is in fact supported by the exact discreteness of the microstructured beam. A comparison of the discrete and the continuous problems (for both static and dynamics analyses) show the efficiency of the nonlocal-based modelling for capturing scale effects. As it has already been shown for buckling or vibrations studies, small scale effects tend to soften the material in this case.


      PubDate: 2013-11-25T01:38:29Z
       
  • Size effects in ductile failure of porous materials containing two
           populations of voids
    • Abstract: Publication date: Available online 22 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): L. Zybell , G. Hütter , T. Linse , U. Mühlich , M. Kuna
      The ductile failure behavior of porous materials containing two populations of voids of different size is investigated numerically by means of 3D cell model calculations. In contrast to previous studies a non-local Gurson model is used to describe the secondary void population in the matrix material. Due to the internal length scale incorporated in the non-local model, it is possible to describe the size of the secondary voids in the matrix material. The results are obtained for loading states with different stress triaxialities and Lode parameters. The influence of the size of the secondary voids is analyzed and it is shown that larger secondary voids lead to a higher stress carrying capacity. This size effect is studied for different primary void arrangements. Furthermore, the strain and primary void volume fraction at the onset of coalescence are presented and cross references to experimental findings are drawn.


      PubDate: 2013-11-25T01:38:29Z
       
  • Energy loss due to adhesion in longitudinal impact of elastic cylinders
    • Abstract: Publication date: Available online 23 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): U.B. Jayadeep , M.S. Bobji , C.S. Jog
      Adhesive interaction between impacting bodies can cause energy loss, even in an otherwise elastic impact. Adhesion force induces tensile stress in the bodies, which modifies the stress wave profile and influences the restitution behaviour. We investigate this effect by developing a finite element framework, which incorporates a Lennard-Jones-type potential for modeling the adhesive interaction between volume elements. With this framework, the classical problems in contact mechanics can be revisited without the restrictive surface-force approximation. In this paper, we study the longitudinal impact of an elastic cylinder on a rigid half-space with adhesion. In the absence of adhesion, this problem reduces to the impact between two identical cylinders in which there is no energy loss. Adhesion causes a fraction of energy in the stress waves to remain in the cylinder as residual stress waves. This apparent loss in kinetic energy is shown to be a unique function of maximum tensile strain energy. We have developed a 1-D model in terms of interaction force parameters, velocity and material properties to estimate the tensile stain energy. We show that this model can be used to predict practically important phenomena like capture wherein the impacting bodies stick together.


      PubDate: 2013-11-25T01:38:29Z
       
  • Coupled thermoelastic effect in free vibration analysis of anisotropic
           multilayered plates and FGM plates by using a variable-kinematics Ritz
           formulation
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Fiorenzo A. Fazzolari , Erasmo Carrera
      A fully coupled thermoelastic formulation is developed to deal with free vibration analysis of anisotropic composite plates and isotropic/sandwich FGM plates. The proposed formulation is developed by combining refined hierarchical plate models and a trigonometric Ritz method. The temperature is considered as a primary variable and allows the evaluation of the temperature field effects in the free vibration analysis. The temperature profile across the plate thickness is always modeled with a layer-wise kinematics description, nevertheless both equivalent single layer and layer-wise approaches are properly and effectively used for the displacement variables. In the 2D and quasi-3D higher-order variable-kinematics plate theories, each displacement variable, in the displacement field, is treated independently from the others. Such artifice allows to select scrupulously each expansion order for each primary variable regarding to the required accuracy and the computational cost. So-called Ritz fundamental primary nuclei related to the coupled thermal and mechanical fields are generated by virtue of an unconventional principle of virtual displacement accounting for the internal thermal virtual work to reproduce the coupling effect. Each fundamental primary nucleus is mathematically invariant with respect to the used kinematics description, the employed expansion orders and the chosen Ritz functions. The thermoelastic coupling is investigated in terms of natural frequencies and the effect of stacking sequence and length-to-thickness ratio for lower and higher modes is discussed.


      PubDate: 2013-11-25T01:38:29Z
       
  • Enhanced continuum poromechanics to account for adsorption induced
           swelling of saturated isotropic microporous materials
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): R. Vermorel , G. Pijaudier-Cabot
      Poromechanics offers a consistent theoretical framework for describing the mechanical response of porous solids fully or partially saturated with a fluid phase. When dealing with fully saturated microporous materials, which exhibit pores of the nanometer size, effects due to adsorption and confinement of the fluid molecules in the smallest pores must be accounted for. From the mechanical point of view, these phenomena result into volumetric deformations of the porous solid, the so-called “swelling” phenomenon. The present work investigates how the poromechanical theory may be refined in order to describe such adsorption and confinement induced effects in microporous solids. Poromechanics is revisited in the context of isotropic microporous materials with generic pore size distributions. The new formulation introduces an effective pore pressure, defined as a thermodynamic variable at the representative volume element scale (mesoscale), which is related to the overall mechanical work of the confined fluid. Accounting for the thermodynamic equilibrium of the system, we demonstrate that the effective pore pressure depends on macroscopic variables, such as the bulk fluid pressure, the temperature and the total and excess adsorbed quantity of fluid. As an illustrating example, we apply the model to compute strains and variations of porosity in the case of the methane and carbon dioxide sorption on coal. Agreement with experimental data found in the literature is observed.


      PubDate: 2013-11-25T01:38:29Z
       
  • A parametric study on the buckling of functionally graded material plates
           with internal discontinuities using the partition of unity method
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): S. Natarajan , S. Chakraborty , M. Ganapathi , M. Subramanian
      In this paper, the effect of local defects, viz., cracks and cutouts on the buckling behaviour of functionally graded material plates subjected to mechanical and thermal load is numerically studied. The internal discontinuities, viz., cracks and cutouts are represented independent of the mesh within the framework of the extended finite element method and an enriched shear flexible 4-noded quadrilateral element is used for the spatial discretization. The properties are assumed to vary only in the thickness direction and the effective properties are estimated using the Mori-Tanaka homogenization scheme. The plate kinematics is based on the first order shear deformation theory. The influence of various parameters, viz., the crack length and its location, the cutout radius and its position, the plate aspect ratio and the plate thickness on the critical buckling load is studied. The effect of various boundary conditions is also studied. The numerical results obtained reveal that the critical buckling load decreases with increase in the crack length, the cutout radius and the material gradient index. This is attributed to the degradation in the stiffness either due to the presence of local defects or due to the change in the material composition.


      PubDate: 2013-11-25T01:38:29Z
       
  • Static characterization and pull-in voltage of a micro-switch under both
           electrostatic and piezoelectric excitations
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Hamed Raeisifard , Mansour Nikkhah Bahrami , Aghil Yousefi-Koma , Hafez Raeisi Fard
      In this paper, a comprehensive model of a micro-switch with both electrostatic and piezoelectric actuators, which accounts for the nonlinearities due to inertia, curvature, electrostatic forces and piezoelectric actuator, is presented to demonstrate the mechanical characteristics of such a micro-system. Dynamic equations of this model have been derived by the Lagrange method and solved by the Galerkin method using five modes. The micro-switch beam has been assumed as an elastic Euler-Bernoulli beam with clamped-free end conditions. The electrostatic actuation results are compared with other existing experimental and numerical results. Whereas the major drawback of electrostatically actuated micro-switches is the high driving voltage, using the piezoelectric actuator in these systems can provide less driving voltage and control the pull-in voltage. The study demonstrates that although the effect of nonlinearity due to electrostatic forces on the deflection is larger than other ones, yet a linear behavior can be observed through the balance between nonlinear terms. There are three ways to influence the design and control of the mechanical characteristics of this micro-switch: the softening effect due to electrostatic actuation, the hardening effect due to piezoelectric actuation, and varying the length and thickness of the piezoelectric actuator.


      PubDate: 2013-11-21T01:38:06Z
       
  • Free vibration analysis of functionally graded carbon nanotube-reinforced
           composite cylindrical panel embedded in piezoelectric layers by using
           theory of elasticity
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): A. Alibeigloo
      In this paper free vibration behavior of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) cylindrical panel embedded in piezoelectric layers with simply supported boundary conditions is investigated by using three-dimensional theory of elasticity. By using Fourier series expansion along the longitudinal and latitudinal directions and state space technique across the thickness direction, state space differential equations are solved analytically. The traction-free surface conditions then give rise to the characteristic equation for natural frequencies. Accuracy and convergence of the present approach are validated by comparing the numerical results with those found in literature. In addition, the effects of volume fraction of CNT, four cases of FG-CNTRC, piezoelectric layer thickness, mid radius to thickness ration and modes number on the vibration behavior of the hybrid cylindrical panel are also examined.


      PubDate: 2013-11-17T01:36:15Z
       
  • First–principles study of the dislocation core structures on basal
           plane in magnesium
    • Abstract: Publication date: Available online 16 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Tou-Wen Fan , Quan Zhang , Li Ma , Ping-Ying Tang , Bi-Yu Tang , Li-Ming Peng , Wen-Jiang Ding
      The core properties of dislocations on (0001) basal plane in pure magnesium, including screw, 30°, 60° and edge dislocations, have been studied by combining the generalized stacking fault energies from first–principles calculation with the improved 2D Peierls–Nabarro model. The calculated results showed that all full dislocations have dissociated into two partial dislocations. With increasing the angle between the dislocation line and Burgers vector, the distance between the two partial dislocations is increased. Then the dislocation line energy surfaces ET as a functional of shift displacement t of dislocation center and separation distance d between the partials are calculated, several stable configurations with local minimum energy have been found for screw and 60° dislocations, while only one stable configuration is formed in 30° and edge dislocations. Finally, the Peierls energies and Peierls stresses along the reaction path have been determined. The calculated Peierls energies for screw and 60° dislocation lines along direction [1 2 ¯ 10] are energetically larger than 30° and edge dislocation lines along [10 1 ¯ 0]. The obtained Peierls stresses are in agreement with experimental values and other theoretical calculations.
      Graphical abstract image

      PubDate: 2013-11-17T01:36:15Z
       
  • Legendre spectral element method with nearly incompressible materials
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Y.T. Peet , P.F. Fischer
      We investigate convergence behavior of a spectral element method based on Legendre polynomial shape functions solving linear elasticity equations for a range of Poisson's ratios of a material. We document uniform convergence rates independent of Poisson's ratio for a wide class of problems with both straight and curved elements in two and three dimensions, demonstrating locking-free properties of the spectral element method with nearly incompressible materials. We investigate computational efficiency of the current method without a preconditioner and with a simple mass-matrix preconditioner, however no attempt to optimize a choice of a preconditioner was made.


      PubDate: 2013-11-17T01:36:15Z
       
  • Well-posedness of an integro-differential equation with positive type
           kernels modeling fractional order viscoelasticity
    • Abstract: Publication date: Available online 14 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Fardin Saedpanah
      A hyperbolic type integro-differential equation with two weakly singular kernels is considered together with mixed homogeneous Dirichlet and non-homogeneous Neumann boundary conditions. Existence and uniqueness of the solution is proved by means of Galerkin’s method. Regularity estimates are proved and the limitations of the regularity are discussed. The approach presented here is also used to prove regularity of any order for models with smooth kernels, that arise in the theory of linear viscoelasticity, under the appropriate assumptions on data.


      PubDate: 2013-11-17T01:36:15Z
       
  • Viscous interfaces as source for material creep: a continuum
           micromechanics approach
    • Abstract: Publication date: Available online 15 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): M. Shahidi , B. Pichler , Ch. Hellmich
      It is generally agreed upon that fluids may play a major role in the creep behavior of materials comprising heterogeneous microstructures and fluid-filled porosity at small length scales. In more detail, nanoconfined fluid-filled interfaces are typically considered to act as a lubricant, once electrically charged solid surfaces start to glide along fluid sheets, while the fluid is typically in a liquid crystal state, which refers to an “adsorbed”, “ice-like”, or “glassy” structure of fluid molecules. Here, we aim at translating this interface behavior into apparent creep laws at the continuum scale of materials consisting of one non-creeping solid matrix with embedded fluid-filled interfaces. To this end, we consider a linear relationship between (i) average interface dislocations and (ii) corresponding interface tractions, with an interface viscosity as the proportionality constant. Homogenization schemes for eigenstressed heterogeneous materials are used to upscale this interface behavior to the much larger observation scale of a matrix-inclusion composite comprising an isotropic and linear elastic solid matrix, as well as interacting circular and parallel interfaces embedded into the aforementioned matrix. Both the obtained characteristic creep and relaxation times, describing exponentially decaying viscoelastic phenomena, increase with increasing interface size and viscosity, as well as with decreasing elastic stiffness of the solid matrix; while only the relaxation time decreases with increasing interface density. Accordingly, non-asymptotic creep of hydrated (quasi-)crystalline materials at higher load intensities may be readily explained through non-stationarity, i.e. spreading, of liquid crystal interfaces throughout solid elastic matrices.


      PubDate: 2013-11-17T01:36:15Z
       
  • Three-dimensional elasticity solution for vibration analysis of
           functionally graded hollow and solid bodies of revolution. Part II:
           Application
    • Abstract: Publication date: Available online 15 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Yegao Qu , Guang Meng
      The semi-analytical method, developed in Part I of this paper, is employed to investigate the free, steady-state and transient vibrations of various FGM bodies of revolution. A comprehensive investigation concerning the convergence, accuracy and efficiency of the method is given for free vibrations of hollow and solid FGM cylinders, cones and spheres with different combinations of free, simply-supported, clamped and elastic-supported boundary conditions. It is shown that the present method enables rapid convergence, stable numerical operation and very high computational accuracy. Both lower- and higher-order frequencies can be accurately obtained by using a small computational effort. The utility and robustness of the method for the application of various polynomial functions are evaluated. New vibration results for FGM bodies of revolution are presented, which could serve as benchmarks for future research. Parametric studies are carried out to highlight the influences of geometrical parameters, boundary conditions, and material profiles on free vibrations of FGM cylinders, cones and spheres. With regard to the forced vibration problems, harmonic responses of hollow and solid cylinders under uniformly axial and normal pressures are calculated, and time domain solutions of FGM cones subjected to several impulsive loads, including a rectangular pulse, a triangular pulse, a half-sine pulse and an exponential pulse, are also examined.


      PubDate: 2013-11-17T01:36:15Z
       
  • Three-dimensional elasticity solution for vibration analysis of
           
    • Abstract: Publication date: Available online 15 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Yegao Qu , Guang Meng
      This is the first of two companion papers which collectively present a novel semi-analytical method and its associated applications for linear vibration analyses of functionally graded bodies (either hollow or solid) of revolution with arbitrary boundary conditions. A modified variational principle combined with a multi-segment partitioning procedure is employed to formulate the theoretical model in the context of three-dimensional theory of elasticity. Displacement variations of each body segment are represented by Fourier series for the circumferential variable and orthogonal polynomials for the meridional and normal variables. The effective material properties of functionally graded bodies are assumed to vary continuously in the normal direction according to general four-parameter power-law distributions in terms of volume fractions of the constituents, and are estimated by Voigt's rule of mixture and Mori-Tanaka's homogenization scheme. The proposed method is capable of handling various combinations of boundary constraints in a unified fashion, including free, simply-supported, clamped and elastic-supported boundary conditions, and allows the use of different polynomials as displacement functions for meridional and normal variables, such as Chebyshev and Legendre orthogonal polynomials as well as hybrid polynomials. Moreover, it permits to deal with the lower- and high-order vibration problems of functionally graded bodies of revolution subjected to dynamic loads of arbitrary type. In Part I, attention is principally focused on the theoretical development and solution methodology of the method. Comprehensive studies on the convergence, accuracy, stability and efficiency of the method are addressed in Part II, where parametric studies concerning the influences of the geometrical parameters, material distributions as well as boundary conditions on free, steady-state and transient vibrations of functionally graded cylinders, cones and spheres are also investigated in detail.


      PubDate: 2013-11-17T01:36:15Z
       
  • A twisted elastica constrained inside a tube
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Sheng-Yo Li , Jen-San Chen
      In this paper we use elastica model to calculate the deformation of a clamped–clamped rod under end twist and constrained inside a straight tube. Unlike most of the previous works, in which only the fully-developed line-contact spiral from end to end was considered, we study the case when both ends of the rod are at the center of the tube cross section. As a consequence, free of contact and point contact may occur in the deformation. The results are compared with those predicted from a previous work using small-deformation theory. Ten deformation patterns from deformation 1–10 are calculated by shooting method, with a possibility of finding more. The deformation sequence forms a smooth load-deflection locus. It is found that the small-deformation theory is capable of finding only the early stage of the deformation sequence from deformation 1 to 5. The elastica model, on the other hand, predicts that the constrained elastica may undergo snapping jump and self-contact when it is under load or displacement control. These deformations cannot be found from a small-deformation theory.


      PubDate: 2013-11-17T01:36:15Z
       
  • New interpretation of cyclic Swift effects
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Oana Cazacu , Benoit Revil-Baudard , Frédéric Barlat
      The generally accepted view is that induced plastic anisotropy is the main reason for accumulation of axial strains during monotonic and cyclic free-end torsion. In this paper, analytical results and numerical simulations using an elastic/plastic model with yielding described by the isotropic form of Cazacu et al. (2006) criterion and isotropic hardening point to another important cause of this phenomenon. It is shown that such phenomenon can occur in an isotropic material, a slight difference between the uniaxial yield stresses in tension and compression of the material leading to a build-up of inelastic axial strains during cyclic torsion at constant strain amplitude. It is demonstrated that the ratio between the uniaxial yield stresses in tension and compression dictates whether permanent shortening or lengthening of the specimen occurs. Furthermore, it is predicted that by axially preloading the material below its plastic threshold and then subject it to strain controlled cyclic torsion under constant axial load, the axial effects may be either reinforced or reduced. Thus, for any given isotropic material it is possible to estimate the value of the constant load and the strain amplitude that need to be prescribed in order to eliminate these effects.


      PubDate: 2013-11-17T01:36:15Z
       
  • A viscoelastic fracture mechanics model for a functionally graded
           materials strip with general mechanical properties
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Zhi-Hai Wang , Li Zhang , Li-Cheng Guo
      In this paper, a viscoelastic fracture mechanics model is developed to investigate crack problem in viscoelastic functionally graded materials (FGMs) with general mechanical properties. Firstly, for the viscoelastic FGMs, the extensional relaxation functions and the relaxation functions of Poisson's ratio are assumed to take the form separable in space and time. Then, according to the correspondence principle, the crack problem of the viscoelastic FGMs is turned into a corresponding elastic crack problem of FGMs with general mechanical properties. In general, for actual FGMs with general mechanical properties, it is difficult to obtain analytical solutions of the governing differential equations. In order to circumvent this problem, a multi-layered model for the FGMs is developed. In the multi-layered model, the mechanical properties of each layer are described by exponential functions. Then, the corresponding elastic crack problem of the FGMs is turned into a group of singular integral equations which can be solved numerically. Based on the correspondence principle and Laplace transform, the stress intensity factors (SIFs) of viscoelastic FGMs can be determined by inverting the transformed SIFs. Some numerical examples are given to study influences of the various material, geometric parameters and loading conditions on the SIFs.


      PubDate: 2013-11-17T01:36:15Z
       
  • Editorial board
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43




      PubDate: 2013-11-13T01:36:27Z
       
  • Deformation of thin chiral plates in strain gradient elasticity
    • Abstract: Publication date: Available online 11 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): D. Ieşan
      In this paper we derive a theory of thin chiral elastic plates in the framework of the strain gradient elasticity. A uniqueness result is established with no definiteness assumption on constitutive coefficients. In the equilibrium theory we derive the conditions under which the traction problem admits solution. The results are used to study the deformation of an infinite plate with a circular hole.


      PubDate: 2013-11-13T01:36:27Z
       
  • A thermomechanical shear lag analysis of short fuzzy fiber reinforced
           composite containing wavy carbon nanotubes
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): M.C. Ray , S.I. Kundalwal
      A novel three-phase shear lag model is derived to study the load transfer characteristics of the short fuzzy fiber reinforced composite (SFFRC) subjected to the thermomechanical loading. The distinctive feature of the SFFRC is that the short carbon fiber reinforcements coated with radially aligned carbon nanotubes (CNTs) are uniformly interlaced in the polymer matrix. The main novelty of the shear lag model derived in this study is that the interactions between the representative volume elements (RVEs) of the SFFRC, the application of the radial and the thermal loads on the RVE, and the radial as well as the axial deformations of different orthotropic constituent phases of the SFFRC have been taken into account. Particular emphasis has been placed on investigating the effect of waviness of CNTs on the load transfer characteristics of the SFFRC when the wavy CNTs are coplanar with either of the two mutually orthogonal planes. In the absence and the presence of the applied radial and thermal loads on the RVE, the shear lag analysis revealed that if the wavy CNTs are coplanar with the axial plane of the carbon fiber such that the amplitudes of the CNTs are parallel to the length of the carbon fiber then the load transfer characteristics of the SFFRC are significantly improved over those of the composite with and without the straight CNTs. The limiting value of the effective aspect ratio of the carbon fiber is also found for the efficient load transfer to the carbon fiber.


      PubDate: 2013-11-13T01:36:27Z
       
  • Strain gradient plasticity analysis of the influence of grain size and
           distribution on the yield strength in polycrystals
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Carl F.O. Dahlberg , Jonas Faleskog
      Plane strain models of polycrystalline microstructures are investigated using strain gradient plasticity (SGP) and a grain boundary (GB) deformation mechanism. The microstructures are constructed using a non-linear constrained Voronoi tessellation so that they conform to a log-normal distribution in grain size. The SGP framework is used to model the grain size dependent strengthening and the GB deformation results in a cut-off of this trend below a certain critical grain size. Plastic strain field localization is discussed in relation to the non-local effects introduced by SGP and a material length scale. A modification of the Hall–Petch relation that accounts for, not only the mean grain size, but also the statistical size variation in a population of grains is proposed.


      PubDate: 2013-11-09T01:43:33Z
       
  • A kinematic enriched plane state formulation for the analysis of masonry
           panels
    • Abstract: Publication date: Available online 8 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Daniela Addessi , Elio Sacco
      A kinematic enriched formulation for the analysis of the in-plane behavior of regular masonry walls is proposed in order to overcome the limits of the typical plane stress and plane strain assumptions. The boundary value problem for the masonry RVE subjected to periodic boundary conditions is formulated for the enriched plane state. In particular, the displacement field is represented assuming that the components can be written using the separation of variables; in fact, they are obtained as product of in-plane and transversal functions. The in-plane displacement components are expressed as the superposition of a known field, depending on the macroscopic deformations applied to the RVE, and a periodic perturbation described as an even function of the transversal coordinate. The bending effects is avoided representing the out-of-plane displacement field in terms of odd functions of the transversal coordinate. A 2D finite element is formulated and used for performing micro-mechanical and homogenization analyses. Numerical results are compared with analytical ones in order to assess the accuracy of the numerical procedure. Results obtained by employing the proposed model are compared with the ones evaluated on the basis of the classical plane stress, plane strain, generalized plane strain assumptions and with the three-dimensional solution. Finally, the proposed kinematically enriched model is used to derive the elastic domain of the masonry material.


      PubDate: 2013-11-09T01:43:33Z
       
  • Calculation of interfacial stresses in composites containing elliptical
           inclusions of various types
    • Abstract: Publication date: March–April 2014
      Source:European Journal of Mechanics - A/Solids, Volume 44
      Author(s): Jungki Lee , Sangmin Oh , Ajit Mal
      A volume integral equation method (VIEM) is used to study elastostatic problems in an unbounded elastic solid containing multiple elliptical inclusions of arbitrary orientation subject to uniform tensile stress at infinity. The inclusions are assumed to be long parallel elliptical cylinders composed of isotropic or anisotropic elastic materials and perfectly bonded to the isotropic matrix. The solid is assumed to be under plane strain on the plane normal to the cylinders. In contrast to previous studies cited in this paper where only one or a few specific types of inclusions were considered, a detailed analysis of the stress field at the matrix-inclusion interface for square and hexagonal packing arrays is carried out herein, taking into account different values for the number, aspect ratio, orientation angle and concentration of the elliptical inclusions. The accuracy and efficiency of the method are examined through comparison with results obtained from analytical and finite element methods.


      PubDate: 2013-11-09T01:43:33Z
       
  • Two and three-dimensional boundary element formulations of compressible
           isotropic, transversely isotropic and orthotropic viscoelastic layers of
           arbitrary thickness, applied to the rolling resistance of rigid cylinders
           and spheres
    • Abstract: Publication date: Available online 8 November 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Gérard-Philippe Zéhil , Henri P. Gavin
      New two-dimensional and three-dimensional boundary element formulations of compressible viscoelastic layers of arbitrary thickness are presented in this work. The formulations are derived in increasing order of complexity for: (i) compressible isotropic layers, (ii) transversely isotropic layers, and (iii) fully orthotropic layers. It is further shown that existing 2D and 3D models for incompressible isotropic layers may be regarded as particular instances of case (i). The proposed formulations are based on Fourier series and support any linear viscoelastic material model characterized by general frequency-domain master-curves. These approaches result in a compliance matrix for the layer’s upper boundary, which includes the effects of steady-state motion. This characterization may be used as a component in various problem settings to generate sequences of high fidelity solutions for varying parameters. The proposed modeling techniques are applied, in combination with appropriate contact solvers, to the rolling resistance of rigid cylinders and spheres on compressible isotropic, transversely isotropic and orthotropic layers. The latter case reveals that the dissipated power varies with the direction of motion, which suggests new ways of optimizing the level of damping in various engineering applications of very high impact. Interesting lateral viscoelastic effects resulting from material asymmetry are unveiled. These phenomena could be harnessed to achieve smooth and ‘invisible’ guides across three-dimensional viscoelastic surfaces, and hence suggest new ways of controlling trajectories, with a broad range of potential applications.


      PubDate: 2013-11-09T01:43:33Z
       
  • Biaxial wrinkling analysis of composite-faced sandwich plates with soft
           core using improved high-order theory
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): S.M.R. Khalili , M.M. Kheirikhah , K. Malekzadeh Fard
      In the present paper, an improved high-order theory is used for wrinkling analysis of sandwich plates with soft orthotropic core. Third-order plate theory is used for the facesheets and quadratic and cubic functions are assumed for transverse and in-plane displacements of the core, respectively. Continuity conditions for transverse shear stresses at the interfaces as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of the plate are satisfied. The nonlinear Von-Karman type relations are used to obtain strains. Also, the transverse flexibility and transverse normal strain and stress of the orthotropic core are considered. The equations of motion and boundary conditions are derived by principle of minimum potential energy. Analytical solution for static analysis of simply supported sandwich plates under biaxial in-plane compressive loads is presented using Navier's solution. The effect of geometrical parameters of the facesheets and the core and the biaxial loads ratio are studied on the buckling and wrinkling behavior of sandwich plates. Comparison of the present results with the published results in the literature for the special case, confirms the accuracy of the proposed theory. Results showed that the increase in the biaxial load ratio, cause to change the direction of wrinkling wave propagation.


      PubDate: 2013-10-28T09:04:30Z
       
  • Thermal vibration and transient response of magnetostrictive functionally
           graded material plates
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): C.C. Hong
      The results of functionally graded material (FGM) plate with mounted magnetostrictive layer are investigated in thermal vibration and transient response by using the generalized differential quadrature (GDQ) method. The modified shear correction coefficient can be obtained based on the total strain energy equivalence principle. The computational real value solutions of Terfenol-D FGM plate with four edges in simply supported boundary conditions are obtained for the center displacement. Some parametric effects on the Terfenol-D FGM plates are analyzed, there are: shear correction coefficient values, thickness of mounted magnetostrictive layer, control gain values, temperature of environment and power law index of FGM. The effect of different mechanical boundary conditions on the results of numerical GDQ method is also investigated.


      PubDate: 2013-10-28T09:04:30Z
       
  • Isogeometric analysis of laminated composite and sandwich plates using a
           new inverse trigonometric shear deformation theory
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): Chien H. Thai , A.J.M. Ferreira , S.P.A. Bordas , T. Rabczuk , H. Nguyen-Xuan
      This paper presents a new inverse tangent shear deformation theory (ITSDT) for the static, free vibration and buckling analysis of laminated composite and sandwich plates. In the present theory, shear stresses are vanished at the top and bottom surfaces of the plates and shear correction factors are no longer required. A weak form of the static, free vibration and buckling models for laminated composite and sandwich plates based on ITSDT is then derived and is numerically solved using an isogeometric analysis (IGA). The proposed formulation requires C 1-continuity generalized displacements and hence basis functions used in IGA fulfill this requirement. Numerical examples are provided to show high efficiency of the present method compared with other published solutions.


      PubDate: 2013-10-28T09:04:30Z
       
  • Two-dimensional theory of piezoelectric shells considering surface effect
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): Chunli Zhang , Jun Zhu , Weiqiu Chen , Ch. Zhang
      Two-dimensional (2D) general equations of piezoelectric shells with nano-thickness are presented in an orthogonal curvilinear coordinate system, in which the surface effect is considered by treat the shell as a bulk core plus two surface layers. The general 2D equations can be directly degenerated into those of particular shells such as flat plates, cylindrical shells and so on by setting the Lamé coefficients and the principal radii of curvature to certain values. Using the derived 2D equations of cylindrical shells, the free vibration of a radially polarized piezoelectric cylindrical shell of finite length is analyzed. Numerical results show that the surface effect has a remarkable influence on the natural frequency of the shell at the nano-scale.


      PubDate: 2013-10-28T09:04:30Z
       
  • Fast computation of an infinite, longitudinally-varying and harmonic strip
           load acting on a viscoelastic half-space
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): Robert Arcos , Arnau Clot , Jordi Romeu , Sara R. Martín
      In the context of the developing of a numerically efficient model of railway induced ground vibrations, the problem of an infinite, longitudinally-varying and harmonic strip load acting on the surface of a viscoelastic half-space is reformulated in order to improve its numerical evaluation. On one hand, the static integrands of this specific problem are modified and introduced into the original integrands to reduce their spectral content at high wavenumbers, saving computational time needed for the numerical integration. On the other hand, a change of variable is applied on the displacements integral solutions resulting on frequency independent integrands. These formulae allow to obtain the displacement solution in the complete x-y-ω field easier and, mostly, faster.


      PubDate: 2013-10-24T00:36:46Z
       
  • A two-director Cosserat rod model using unconstrained quaternions
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): Dario Genovese
      Starting from a constrained three-dimensional analysis, we propose a new model for an initially curved Cosserat rod with two independent directors, in which the cross-section can inflate and ovalize. The usage of unconstrained quaternions gets rid of the non-linear constraints and singularities in the parametrization of objective strains, related to the orthonormality of rotation matrices. Furthermore, the classic definitions of curvatures and twist have been modified and tuned for a linear constitutive law (i.e. a linear relationship between one-dimensional stresses and strains). The capabilities and the limitations of the model in describing the non-linear effects of cross-section deformation on bending and torsion, and usually handled with bi- and three-dimensional theories, are then discussed.


      PubDate: 2013-10-20T00:37:11Z
       
  • Application of Reddy's third-order theory to delaminated orthotropic
           composite plates
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): András Szekrényes
      In this work the third-order shear deformation theory by Reddy is applied and modified to analyze delaminated orthotropic composite plates. The delaminated plate portion is captured by Reddy's traditional theory, while a novel double-plate system is developed for the undelaminated part. It is shown that in the uncracked part four conditions are required to satisfy in symmetrically delaminated plates. The conditions involve the imposition of traction-free boundaries and the interface constraints. These four conditions enable the reduction of the parameters from nine to five in the displacement field. The governing equations show significant coupling among the stress resultants of the uncracked portion, that has to be considered in the continuity conditions between the delaminated and undelaminated parts. To demonstrate the application of the present model a simply-supported delaminated plate subjected to a concentrated force is analyzed. The distribution of the mode-II and mode-III energy release rates and their ratio are calculated using the 3-dimensional J-integral. The finite element model of the plate is also created using brick-type elements. The comparison of the analytical and finite element results shows very good agreement. It is shown that the deformations around the delamination front can be captured by the third-order plate theory with high accuracy.


      PubDate: 2013-09-26T08:10:13Z
       
  • Investigation into the energy dissipation of a lap joint using the
           one-dimensional microslip friction model
    • Abstract: Publication date: January–February 2014
      Source:European Journal of Mechanics - A/Solids, Volume 43
      Author(s): Huifang Xiao , Yimin Shao , Jinwu Xu
      In this paper, the energy dissipation in a mechanical lap joint is studied using the one-dimensional microslip friction model by incorporating the effect of interface tangential contact stiffness. A non-uniform pressure distribution of exponent law at the interface is considered and the resulted distinct stick-slip transitions along the contact interface are presented. Expressions of the critical slip loads giving rise to stick-slip transitions along the contact interface are determined. The loading force–displacement curves for different pressure distribution laws and different interface tangential stiffness are obtained and compared with each other. The hysteresis curves of the oscillating tangential contact forces versus tangential displacements and the dissipated energy at the contact are determined. It is shown that a classical power-law behavior is predicted between the energy dissipation and the applied tangential force. However, the exponents of the power-law are not the theoretical cubic but vary with interface stiffness and pressure distributions. The obtained results suggest that the joint interface tangential stiffness and interfacial pressure distribution are reasons for the varying exponent values obtained in experimental work.


      PubDate: 2013-09-26T08:10:13Z
       
  • Pre-kinking analysis of a constant moving crack in a magnetoelectroelastic
           strip under in-plane loading
    • Abstract: Publication date: Available online 5 September 2013
      Source:European Journal of Mechanics - A/Solids
      Author(s): Keqiang Hu , Zengtao Chen , Zheng Zhong
      A constant moving crack in a magnetoelectroelastic strip under in-plane mechanical, electric and magnetic loading is considered for impermeable and permeable crack surface boundary conditions, respectively. Fourier transform is applied to reduce the mixed boundary value problem of the crack to dual integral equations, which are further transformed into Fredholm integral equations of the second kind. Steady state asymptotic fields near the crack tip are obtained and the corresponding field intensity factors are defined. The exact solution for a cracked infinite magnetoelectroelastic material can be recovered if the width of the strip tends to infinity. The crack speed and the geometric size of the strip affect the singular field distribution around the crack tip and the influences of electric and magnetic loading on the crack tip fields are discussed. The crack kinking phenomenon is investigated by applying the maximum hoop stress intensity factor criterion.


      PubDate: 2013-09-08T00:34:27Z
       
 
 
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