Rong-gang Zhang^1,2, Hong-tao Zhang³ , Yu-xing Bai³, Jian-ling Gao³, Lai-yong Zhang² , Bing-ye Xu¹

CMC-Computers, Materials & Continua, Vol.20, No.3, pp. 243-250, 2010, DOI:10.3970/cmc.2010.020.243

Abstract Based on the upper bound theorem, the fire resistance is studied using the combination of element collapse mechanisms of steel frames, where the element collapse mechanisms are automatically determined from independent mechanisms. The fire limit load is calculated by solving a nonlinear mathematical programming. The computing procedure is programmed by FORTRAN language. Results show that this method is useful to find the collapse mechanism with the lowest fire limit load, which can provide a theoretical and practical way for the fire design of steel frame structure. More >

X. H. Du¹, X. P. Shen¹

CMC-Computers, Materials & Continua, Vol.20, No.3, pp. 225-242, 2010, DOI:10.3970/cmc.2010.020.225

Abstract Aim of this paper is to estimate the integrity of liquefied natural gas (LNG) prestressed storage tank under seismic influence. The coupled Eulerian-Lagrangian (CEL) analysis technique is used to simulate the fluid-structure interaction between LNG and the cylinder of LNG prestressed storage tank. The 3-D model of LNG has been dispersed by Eulerian mesh that is different from traditional analysis method which is called the added mass method. Meanwhile, both of the 3-D models of prestressed rebar and concrete structure are dispersed by Lagrangian mesh. Following conclusions are obtained: 1) Natural frequency of the whole model has been obtained by… More >

X.P. Shen, A. Diaz¹, T. Sheehy²

CMC-Computers, Materials & Continua, Vol.20, No.3, pp. 205-224, 2010, DOI:10.3970/cmc.2010.020.205

Abstract This paper presents a case study for the design of a mud-weight window (MWW) with three-dimensional (3-D), finite-element (FE) tools for subsalt wells. The trajectory of the target well penetrates a 7 km thick salt body. A numerical scheme has been proposed for calculating the shear failure gradient (SFG) and fracture gradient (FG) with 3-D FE software. User subroutines have been developed to address non-uniform pore-pressure distribution. A series of FE calculations were performed to obtain the MWW of the target wellbore, which consists of the SFG and FG for the subsalt sections. Although no reverse faulting structure exists in… More >

X.P. Shen¹, J.L. Feng²

CMC-Computers, Materials & Continua, Vol.20, No.2, pp. 185-204, 2010, DOI:10.3970/cmc.2010.020.185

Abstract The characteristic length of a gradient-dependent damage model is a key parameter, which is usually regarded as the length of damage process zone (DPZ). Value and evolution of the size of DPZ were investigated by both a numerical method and an experimental manner. In the numerical study, the geometrical model adopted was a set of four-point shearing beams; the numerical tool used was the Abaqus/Explicit software. The distance between the front and end of a complete DPZ was obtained. Values of strain components at these points were given out at given time points. The experimental study of the evolution process… More >

Haofeng Chen¹

CMC-Computers, Materials & Continua, Vol.20, No.2, pp. 159-184, 2010, DOI:10.3970/cmc.2010.020.159

Abstract In this paper a state-of-the-art numerical method is discussed for the evaluation of the shakedown and ratchet limits for an elastic-perfectly plastic body subjected to cyclic thermal and mechanical load history. The limit load or collapse load, i.e. the load carrying capacity, is also determined as a special case of shakedown analysis. These design limits in plasticity have been solved by characterizing the steady cyclic state using a general cyclic minimum theorem. For a prescribed class of kinematically admissible inelastic strain rate histories, the minimum of the functional for these design limits are found by a programming method, the Linear… More >

Jie Qu^1,2, Bingye Xu³, Quanlin Jin⁴

CMC-Computers, Materials & Continua, Vol.20, No.2, pp. 119-158, 2010, DOI:10.3970/cmc.2010.020.119

Abstract Large and complex macro-micro coupled constitutive models, which describe metal flow and microstructure evolution during metal forming, are sometimes overparameterized with respect to given sets of experimental datum. This results in poorly identifiable or non-identifiable model parameters. In this paper, a systemic parameter identification method for the large macro-micro coupled constitutive models is proposed. This method is based on the global and local identifiability analysis, in which two identifiability measures are adopted. The first measure accounts for the sensitivity of model results with respect to single parameters, and the second measure accounts for the degree of near-linear dependence of sensitivity… 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 >

Richard K. F. Lee¹, James M. Hill²

CMC-Computers, Materials & Continua, Vol.20, No.1, pp. 85-100, 2010, DOI:10.3970/cmc.2010.020.085

Abstract In this study, we investigate the mechanics of a metallofullerene shuttle memory device, comprising a metallofullerene which is located inside a closed carbon nanotube. The interaction energy for the system is obtained from the 6-12 Lennard-Jones potential using the continuum approximation, which assumes that a discrete atomic structure can be replaced by an average atomic surface density. This approach shows that the system has two equal minimum energy positions, which are symmetrically located close to the tube extremities, and therefore it gives rise to the possibility of being used as a two-state memory device. On one side the encapsulated metallofullerene… 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 >