Qunfeng Liu^1,2, Liang Wang¹, gping Shen¹

CMC-Computers, Materials & Continua, Vol.46, No.2, pp. 105-123, 2015, DOI:10.3970/cmc.2015.046.105

Abstract Molecular dynamics simulations have been performed to investigate the effects of cross section geometry and shape on the mechanical behaviors of silicon nanowires (Si NWs) under tensile loading. The results show that elasticity of <100> rectangular Si NWs depends on their cross section aspect ratios while the elastic limits of <110> and <111> wires show geometry independence. Despite the significant influence of axial orientation, both yield stress and Young's Modulus show the remarkable shape dependence for wires with various regular cross sections. Additionally, underlying mechanism for the geometry and shape effects on mechanical behavior are discussed based on the fundamental… More >

M.R. Akbari¹, J. Ghanbari^1,2

CMC-Computers, Materials & Continua, Vol.45, No.3, pp. 187-202, 2015, DOI:10.3970/cmc.2015.045.187

Abstract Exact analytical solution for functionally graded hollow discs under internal pressure, thermal load and rotation are provided in this paper. Material properties of discs, i.e. elastic modulus, density and thermal expansion coefficient are assumed to vary in radial direction. Two power functions are assumed for property dependency to study various types of functional grading of materials in the discs. Assuming small deformations, a differential equation is obtained and solved for the Airy stress function. The effects of various grading functions on the stress and deformation distribution are studied and an optimum value for the power is obtained. More >

Jianfeng Lu¹, Xu Liang^1,2, Shuling Hu^1,2

CMC-Computers, Materials & Continua, Vol.45, No.3, pp. 145-162, 2015, DOI:10.3970/cmc.2015.045.145

Abstract Flexoelectricity phenomenologically describes the universal electromechanical coupling effect between electric polarization and strain gradient, and electric field gradient and elastic strain. In contrast to piezoelectricity which is invalid in materials with inversion symmetry, flexoelectricity exists, commonly, in all solid dielectrics. In this paper, a summary of the research on flexoelectricity is presented to illustrate the development of this topic. Flexoelectricity still have many open questions and unresolved issues in the developing field, although it has attracted a surge of attention recently. Here we review the theoretical investigations and experimental studies on flexoelectricity, and the aim of the current paper is… More >

Neeraj Dubey¹, Geeta Agnihotri¹

CMC-Computers, Materials & Continua, Vol.45, No.1, pp. 39-56, 2015, DOI:10.3970/cmc.2015.045.039

Abstract In this paper, midrib of coconut palm leaves (MCL) was investigated for the purpose of development of natural fiber reinforced polymer matrix composites. A new natural fiber composite as MCL/polyester is developed by the hand lay-up method, and the material and mechanical properties of the fiber, matrix and composite materials were evaluated. The effect of fiber content on the tensile, flexural, impact, compressive strength and heat distortion temperature (HDT) was investigated. It was found that the MCL fiber had the maximum tensile strength, tensile modulus flexural strength, flexural modulus and Izod impact strength of 177.5MPa, 14.85GPa, 316.04MPa and 23.54GPa, 8.23KJ/m²… More >

Wei Zhang^1,2, Pengcheng Ni², Bingfei Liu^1,3

CMC-Computers, Materials & Continua, Vol.44, No.2, pp. 105-122, 2014, DOI:10.3970/cmc.2014.044.105

Abstract Analytical expressions have been derived for the through thickness stresses of a Functional graded materials (FGMs) thin plate subjected to thermal loading, pure bending and thermo-mechanical coupling, respectively. The structure is comprised of a metallic layer, a ceramic layer and a functional graded layer. Continuous gradation of the volume fraction in the FGM layer is modeled in the form of an "m" power polynomial of the coordinate axis in thickness direction of the plate. Numerical scheme of discretizing the continuous FGM layer with different graded distributions such as linear (m=1), quadratic (m=2) and square root (m=0.5) has been developed by… More >

Yuping Zhu^1,2, Tao Chen¹, Kai Yu¹

CMC-Computers, Materials & Continua, Vol.43, No.2, pp. 97-108, 2014, DOI:10.3970/cmc.2014.043.097

Abstract Based on an existing micromechanical constitutive model for Ni2MnGa ferromagnetic shape memory alloy single crystals, a three-dimensional quasi-static isothermal incremental constitutive model that is suitable for finite element analysis is derived by using Hamilton's variational principle. This equation sets up the coupling relation between the magnetic vector potential and the mechanical displacement. By using the incremental equation and ANSYS software, the mechanical behaviors of martensitic variant reorientation for Ni2MnGa single crystals are analyzed under magneto-mechanical coupling action. And the finite element results agree well with the experimental data. The methods used in the paper can well describe the mechanical behaviors… More >

Yu Miao¹, Zhe Chen¹, Qiao Wang^1,2, Hongping Zhu¹

CMC-Computers, Materials & Continua, Vol.43, No.1, pp. 49-74, 2014, DOI:10.3970/cmc.2014.043.049

Abstract In this paper, an improved multi-domain model based on the hybrid boundary node method (Hybrid BNM) is proposed for mechanical analysis of 3D composites. The Hybrid BNM is a boundary type meshless method which based on the modified variational principle and the Moving Least Squares (MLS) approximation. The improved multi-domain model can reduce the total degrees of freedom (DOFs) compared with the conventional multi-domain solver. It is very suitable for the inclusion-based composites, especially for the composites when the inclusions are solid and totally embedded in the matrix domain. Numerical examples are presented to verify the improved multi-domain model and… More >

H. Zheng^1,2, X. Peng^1,2,3,4, N. Hu^1,3,5

CMC-Computers, Materials & Continua, Vol.41, No.1, pp. 55-84, 2014, DOI:10.3970/cmc.2014.041.055

Abstract The Shakedown of a functionally graded (FG) Bree plate subjected to coupled constant mechanical loading and cyclically varying temperature is analyzed with more accurate approaches and optimized with the genetic algorithm method. The shakedown theorem takes into account material hardening. The variation of the material properties in the thickness of a FG Bree plate is characterized with a piecewise exponential distribution, which can replicate the actual distribution with sufficient accuracy. In order to obtain the best distribution of the mechanical properties in the FG plate, the distribution of the reinforcement particle volume fraction is optimized with the genetic algorithm (GA).… More >

Xue-Qian Fang^1,2, Hong-Wei Liu¹, Yong-Mao Zhao¹, Guo-Quan Nie^1,1 and Jin-Xi Liu¹

CMC-Computers, Materials & Continua, Vol.40, No.2, pp. 145-164, 2014, DOI:10.3970/cmc.2014.040.145

Abstract Electro-elastic surface/interface around nano-sized piezoelectric inclusions shows great effect on the response of piezoelectric nano-structures. In this paper, a theoretical model is proposed to examine the surface/interface effect on the electromechanical responses around a nano-sized elliptical piezoelectric inclusion embedded in an infinite piezoelectric matrix under far-field loading with an arbitrary angle, and the effect of loading angle is considered Combining the conformal mapping technique and electro-elastic surface/interface theory, a closed form solution of this problem is obtained and the interactive effect between the surface/interface and the aspect ratio of the elliptical inclusion is examined. More >

J. Aubry¹, P. Navarro¹, S. Marguet¹, J.-F. Ferrero¹, O. Dorival², L. Sohier³, J.-Y. Cognard³

CMC-Computers, Materials & Continua, Vol.39, No.1, pp. 21-47, 2014, DOI:10.3970/cmc.2014.039.021

Abstract In this paper a numerical model dedicated to the simulation of the mechanical behaviour of polymeric Rohacell foams is presented. The finite elements model is developed at the scale of the microstructure idealized by a representative unit cell: the truncated octahedron. Observations made on micrographs of Rohacell lead to mesh this representative unit cell as a lattice of beam elements. Each beam is assigned a brittle linear elastic mechanical behaviour in tension and an elastoplastic behaviour in compression. The plasticity in compression is introduced as a way to mimic the buckling of the edges of the cells observed in experimental… More >