K. C. Liu¹, S. M. Arnold²

CMC-Computers, Materials & Continua, Vol.35, No.1, pp. 35-65, 2013, DOI:10.3970/cmc.2013.035.035

Abstract It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the influence of many of these scale specific architectural features of woven ceramic composite are examined stochastically at both the macroscale (woven repeating unit cell (RUC)) and structural scale (idealized using multiple RUCs).… More >

Bingfei Liu¹, Guansuo Dui^2,3, Benming Xie¹, Libiao Xin³, Lijun Xue³

CMC-Computers, Materials & Continua, Vol.34, No.1, pp. 83-94, 2013, DOI:10.3970/cmc.2013.034.083

Abstract Functionally Graded Materials (FGMs) are being used in an everexpanding set of applications. For better applications, an analytical methodology using averaging technique of composites is developed to describe the thermo-elastic and thermo-elastoplastic behaviors of a three-layered FGM system subjected to thermal loading Solutions using averaging technique of composites for the stress distributions in a generic FGM system subjected to arbitrary temperature loading conditions are presented. The power-law strain hardening behaviour is assumed for the FGM metallic phase and the stress of the metallic phase are calculated to judge the plastic in this work The stress distributions within the FGM systems… More >

Xue-Qian Fang^1,2, Ming-Juan Huang¹, Jun-Ying Wu³, Guo-Quan Nie¹, Jin-Xi Liu¹

CMC-Computers, Materials & Continua, Vol.33, No.2, pp. 199-211, 2013, DOI:10.3970/cmc.2013.033.199

Abstract In nanocomposites, coated nano-fibers are often used to obtain good performance, and the high interface-to-volume ratio shows great effect on the macroscopic effective properties of nanocomposites. In this study, the effect of interface energy around the unidirectional coated nanofibers on the effective dynamic effective properties is explicitly addressed by effective medium method and wave function expansion method. The multiple scattering resulting from the series coating nano-fibers is reduced to the problem of one typical nano-fiber in the effective medium. The dynamic effective shear modulus is obtained on the basis of the derived imperfect interface conditions. Analyses show that the effect… More >

J. Sladek¹, V. Sladek¹, P. Stanak¹, Ch. Zhang², M. Wünsche²

CMC-Computers, Materials & Continua, Vol.23, No.1, pp. 35-68, 2011, DOI:10.3970/cmc.2011.023.035

Abstract A contour integral method is developed for the computation of stress intensity, electric and magnetic intensity factors for cracks in continuously nonhomogeneous magnetoelectroelastic solids under a transient dynamic load. It is shown that the asymptotic fields in the crack-tip vicinity in a continuously nonhomogeneos medium are the same as in a homogeneous one. A meshless method based on the local Petrov-Galerkin approach is applied for the computation of the physical fields occurring in the contour integral expressions of intensity factors. A unit step function is used as the test functions in the local weak-form. This leads to local integral equations… More >

Le-Le Zhang¹, Xue-Qian Fang¹, Jin-Xi Liu¹, Ji-Hong Ma¹

CMC-Computers, Materials & Continua, Vol.21, No.3, pp. 171-186, 2011, DOI:10.3970/cmc.2011.021.171

Abstract On the basis of continuum surface elasticity, two interacting cylindrical nano-inhomogeneities with surface/interface effect in a small-sized solid under anti-plane shear waves are investigated, and the dynamic stress around the nano-inhomogeneities is analyzed. The wave function expansion method is used to expressed the wave field around the two nano-inhomogeneities. The total wave field is obtained by the addition theorem for cylindrical wave function. Through analysis, it is found that the distance between the two nano-inhomogeneities shows great effect on the dynamic stress in nano composites. The effect of the distance is also related to the properties of the nano-inhomogeneities and… More >

Alamusi¹, Y.L. Liu¹, N. Hu^1,2

CMC-Computers, Materials & Continua, Vol.20, No.2, pp. 101-118, 2010, DOI:10.3970/cmc.2010.020.101

Abstract In this work, we propose a 3 dimensional (3D) numerical model to predict the piezoresistivity behaviors of a nanocomposite material made from an insulating polymer filled by carbon nanotubes (CNTs). This material is very hopeful for its application in highly sensitive strain sensor by measuring its piezoresistivity, i.e., the ratio of resistance change versus applied strain. In this numerical approach, a 3D resistor network model is firstly proposed to predict the electrical conductivity of the nanocomposite with a large amount of randomly dispersed CNTs under the zero strain state. By focusing on the fact that the piezoresistivity of the nanocomposite… More >

Metin Kök^1,2, Erdogan Kanca³

CMC-Computers, Materials & Continua, Vol.18, No.3, pp. 213-236, 2010, DOI:10.3970/cmc.2010.018.213

Abstract In this investigation, a new model was developed to predict the wear rate of Al2O3 particle-reinforced aluminum alloy composites by Genetic Expression Programming (GEP). The training and testing data sets were obtained from the well established abrasive wear test results. The volume fraction of particle, particle size of reinforcement, abrasive grain size and sliding distance were used as independent input variables, while wear rate (WR) as dependent output variable. Different models for wear rate were predicted on the basis of training data set using genetic programming and accuracy of the best model was proved with testing data set. The two-body… More >

Hui- Shen^1,2, Zheng Hong Zhu³

CMC-Computers, Materials & Continua, Vol.18, No.2, pp. 155-182, 2010, DOI:10.3970/cmc.2010.018.155

Abstract This paper investigates the buckling and postbuckling of simply supported, nanocomposite plates with functionally graded nanotube reinforcements subjected to uniaxial compression in thermal environments. The nanocomposite plates are assumed to be functionally graded in the thickness direction using single-walled carbon nanotubes (SWCNTs) serving as reinforcements and the plates' effective material properties are estimated through a micromechanical model. The higher order shear deformation plate theory with a von Kármán-type of kinematic nonlinearity is used to model the composite plates and a two-step perturbation technique is performed to determine the buckling loads and postbuckling equilibrium paths. Numerical results for perfect and imperfect,… More >

J. Wang¹, D. C. C. Lam²

CMC-Computers, Materials & Continua, Vol.17, No.3, pp. 215-232, 2010, DOI:10.3970/cmc.2010.017.215

Abstract Selected elastic moduli of nanocomposites are higher than the elastic moduli of microcomposites. Molecular immobilization and crystallization at the interfaces had been proposed as potential causes, but studies suggested that these effects are minor and cannot be used to explain the magnitude observed in nanocomposites with >3nm particles. Alternately, molecular simulation of polymer deformation showed that rotation gradients can lead to additional molecular rotations and stiffen the matrix. The stiffening is characterized by the nanostiffening material parameter, l2. In this investigation, an analytical expression for nanostiffening in nanocomposites was developed using finite element analysis. The nanostiffening in nanocomposites was determined… More >

Surkay D. Akbarov^1,2, Resat Kosker³, Yasemen Ucan³

CMC-Computers, Materials & Continua, Vol.17, No.2, pp. 77-102, 2010, DOI:10.3970/cmc.2010.017.077

Abstract In the framework of the piecewise homogeneous body model with the use of the three-dimensional geometrically non-linear exact equations of the theory of elasticity, the method for determination of the stress-strain state in the infinite body containing periodically located row of periodically curved fibers is developed. It is assumed that the midlines of the fibers are in the same plane. With respect to the location of the fibers according to each other the sinphase and antiphase curving cases are considered. Numerical results on the effect of the geometrical non-linearity to the values of the self balanced shear and normal stresses… More >