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 >

Wen-Hwa Chen^1,2, Tsung-Yu Huang¹

CMC-Computers, Materials & Continua, Vol.20, No.1, pp. 63-84, 2010, DOI:10.3970/cmc.2010.020.063

Abstract The contact characteristics between a droplet and a microchip/binding site strongly affect the accuracy of self-alignment in the self-assembly of micro-electronic-mechanical systems. This study is mainly to implement the Surface Evolver Program, which is commonly adopted for studying surface shaped by surface tension and other energies, to investigate comprehensively the contact characteristics between the small droplet and the microchip/binding site. The details of changes in the contact line and the contact area when the microchip is subjected to translation, compression, yawing and rolling are drawn. The three-dimensional deformation of the droplet between the microchip and the binding site is also… More >

N.J. Bartle¹, P.D. Gosling¹

CMC-Computers, Materials & Continua, Vol.20, No.1, pp. 19-62, 2010, DOI:10.3970/cmc.2010.020.019

Abstract ETFE cushions are increasingly being used to form high-profile facades and structural forms. This investigation aims to extend an analytical theory of large deformation in order to predict the shape and stress distributions of an un-patterned square ETFE cushion without the need to resort to discretised numerical methods. In order to assess the validity of the theoretical procedure a prototype cushion has been analysed using a finite element simulation. The theoretical procedure is also compared with alternative approximate equations proposed for the design of ETFE cushions. More >

S. N.V.R.K. Kurapati¹, Y. C. Lu¹, F. Yang²

CMC-Computers, Materials & Continua, Vol.20, No.1, pp. 1-18, 2010, DOI:10.3970/cmc.2010.020.001

Abstract The spherical indentation of elastic film /substrate structures is analyzed using the finite element method. The load-displacement curves of the film /substrate structures of various configurations are obtained and analyzed. A generalized power law relation is established, which can be used to analyze the load-displacement curve of elastic film /substrate systems under spherical indentations. The indentation load is dependent on the modulus ratio of the film to the substrate and film thickness. A semi-analytical expression for the power of the power law relation is also obtained as a function of the normalized film thickness and normalized film modulus, which can… More >

Chih-Wen Chang¹

CMC-Computers, Materials & Continua, Vol.19, No.3, pp. 285-314, 2010, DOI:10.3970/cmc.2010.019.285

Abstract In this article, we propose a new numerical approach for solving these multi-dimensional nonlinear and nonhomogeneous backward heat conduction problems (BHCPs). A fictitious time t is employed to transform the dependent variable u(x, y, z, t) into a new one by (1+t)u(x, y, z, t)=: v(x, y, z, t, t), such that the original nonlinear and nonhomogeneous heat conduction equation is written as a new parabolic type partial differential equation in the space of (x, y, z, t, t). In addition, a fictitious viscous damping coefficient can be used to strengthen the stability of numerical integration of the discretized equations… More >

H. Wang¹, Y. Wu², P.D. Wu¹, K.W. Neale³

CMC-Computers, Materials & Continua, Vol.19, No.3, pp. 255-284, 2010, DOI:10.3970/cmc.2010.019.255

Abstract Large strain homogeneous simple shear of Hexagonal Close Packed (HCP) polycrystals is first studied numerically. The analyses are based on the classical Taylor model and the Visco-Plastic Self-Consistent (VPSC) model with various Self-Consistent Schemes (SCSs). In these polycrystal plasticity models, both slip and twinning contribute to plastic deformations. The simple shear results are then extended to the case of solid circular bars under large strain fixed-end torsion, where it is assumed that the solid bar has the same mechanical properties as the element analyzed for large strain simple shear. It is shown that the predicted second-order axial force is very… More >

Adel A. Abdel-Wahab¹, Angelo Maligno¹, Vadim V. Silberschmidt¹

CMC-Computers, Materials & Continua, Vol.19, No.3, pp. 217-238, 2010, DOI:10.3970/cmc.2010.019.217

Abstract Bone is the principal structural component of a skeleton: it assists the load-bearing framework of a living body. Structural integrity of this component is important; understanding of its mechanical behaviour up to failure is necessary for prevention and diagnostic of trauma. In dynamic events such as traumatic falls, involvement in car crash and sports injuries, bone can be exposed to loads exceeding its structural strength and/or fracture toughness. By developing adequate numerical models to predict and describe its deformation and fracture behaviour up to fracture, a detailed study of reasons for, and ways to prevent or treatment methods of, bone… More >

M. Demiral, A. Roy, V. V. Silberschmidt¹

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 199-216, 2010, DOI:10.3970/cmc.2010.019.199

Abstract Static indentation experiments are typically performed to characterize the mechanical properties of a material of interest by a rigid indenter of known geometry to various depths. In contrast, dynamic indentation of materials has not been fully studied. Evaluating material performance under dynamic loading conditions is a challenge and we demonstrate that various modelling schemes may be appropriate for different flavours of dynamic indentation. In order to compare underlying thermo-mechanics and deformation processes in a static and dynamic indentation process, indentation of a rigid indenter into a workpiece to a fixed chosen penetration is extensively studied. A nonlinear strain rate and… More >

Chih-Ping Wu^1,2, Hao-Yuan Li²

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 155-198, 2010, DOI:10.3970/cmc.2010.019.155

Abstract The Reissner mixed variational theorem (RMVT)- and principle of virtual displacements (PVD)-based finite layer methods (FLMs) are developed for the quasi-three-dimensional (3D) free vibration analysis of simply-supported, multilayered composite and functionally graded material (FGM) plates. The material properties of the FGM layers are assumed to obey either an exponent-law exponentially varied with the thickness coordinate or the power-law distributions of the volume fractions of the constituents. In these formulations, the plate is divided into a number of finite layers, where the trigonometric functions and Lagrange polynomials are used to interpolate the in- and out-of-plane variations of the field variables of… More >

A. Rama Ch,ra Murthy^1,2, G.S. Palani¹, Nagesh R. Iyer^1,3, M Srinivasa Pavan¹, Smitha Gopinath¹

CMC-Computers, Materials & Continua, Vol.19, No.2, pp. 135-154, 2010, DOI:10.3970/cmc.2010.019.135

Abstract This paper presents methodologies for fracture analysis of concrete structural components with and without considering tension softening effect. Stress intensity factor (SIF) is computed by using analytical approach and finite element analysis. In the analytical approach, SIF accounting for tension softening effect has been obtained as the difference of SIF obtained using linear elastic fracture mechanics (LEFM) principles and SIF due to closing pressure. Superposition principle has been used by accounting for non-linearity in incremental form. SIF due to crack closing force applied on the effective crack face inside the process zone has been computed using Green's function approach. In… More >