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 >

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.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 >

Hamad F. Al-Harbi¹, Marko Knezevic^1,2, Surya R. Kalidindi^1,3

CMC-Computers, Materials & Continua, Vol.15, No.2, pp. 153-172, 2010, DOI:10.3970/cmc.2010.015.153

Abstract In recent work, we have demonstrated the viability and computational advantages of DFT-based spectral databases for facilitating crystal plasticity solutions in face-centered cubic (fcc) metals subjected to arbitrary deformation paths. In this paper, we extend and validate the application of these novel ideas to body-centered cubic (bcc) metals that exhibit a much larger number of potential slip systems. It was observed that the databases for the bcc metals with a larger number of slip systems were more compact compared to those obtained previously for fcc metals with a smaller number of slip systems. Furthermore, we demonstrate in this paper that… More >

S.Ahmadi¹, B.L.Adams¹ , D.T.Fullwood¹

CMC-Computers, Materials & Continua, Vol.14, No.2, pp. 141-170, 2009, DOI:10.3970/cmc.2009.014.141

Abstract In this paper, a model is introduced to examine the evolution of the microstructure function under plastic deformations. This model is based upon a double continuity relationship that conserves both material particles in the mass space and orientations in the orientation space. An Eulerian description of the motion of material particles and orientations is considered, and continuity relations are derived for both spaces. To show how the proposed model works, two different case studies are provided. In the mass space, the continuity relation is used to examine the evolution of the microstructure function of a two-phase (isotropic) material; while, in… More >

XL Geng¹, KS Zhang², YQ Guo¹, L Qin¹

CMC-Computers, Materials & Continua, Vol.13, No.1, pp. 1-16, 2009, DOI:10.3970/cmc.2009.013.001

Abstract One of the problems in a micro-forming process is the grain size effect, which means the formed part consists of a single grain or several grains sometimes, so the material shows anisotropic or heterogeneous. Under these conditions, a conventional method, which based on the isotropic and homogeneous material hypothesis, is not suitable. In this paper, Experimental investigations into micro deep drawing of the copper single crystal were carried out and the pattern of the micro-cup and the drawing force were observed. Using crystal plasticity theory, a user material subroutine (VUMAT) was built and linked to ABAQUS, and the micro deep… More >

D. S. Liu¹, C. Y. Tsai¹, S. R. Lyu²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 147-164, 2009, DOI:10.3970/cmc.2009.011.147

Abstract This study presents a novel numerical method for extracting the tempe -rature-dependent mechanical properties of the gold and aluminum thin-films. In the proposed approach, molecular dynamics (MD) simulations are performed to establish the load-displacement response of the thin substrate nanoindented at temperatures ranging from 300-900 K. A simple but effective procedure involving genetic algorithm (GA) and finite element method (FEM) is implemented to extract the material constants of the gold and aluminum substrates. The material constants are then used to construct the corresponding stress-strain curve, from which the elastic modulus, yield stress and the tangent modulus of the thin film… More >

B Keerthika¹, Y P Cao², D Raabe¹

CMC-Computers, Materials & Continua, Vol.10, No.3, pp. 243-258, 2009, DOI:10.3970/cmc.2009.010.243

Abstract In this study, effects of the plastic deformation and the time-dependent deformation behavior on the fundamental relations in the Oliver & Pharr method are studied by using finite element analysis based on a viscoelastic-plastic model developed for polymers. The study eventually yields an experimental protocol and using which, the instantaneous modulus of the viscoelastic-plastic materials may be reliably determined. Experiments have been performed on four polymers to verify the conclusions from the numerical analysis. More >

Hamid Sharifi¹ and Augustin Gakwaya¹

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 77-96, 2006, DOI:10.3970/cmc.2006.003.077

Abstract In this paper, an object-oriented modeling of solid material constitutive behavior using the UML notation is presented. Material properties are first classified into large and small deformation kinematical models. In the small deformation package, we keep classes such as Elastic, ElastoPlastic, ViscoElastic and ViscoPlastic. In the large deformation package, we store classes such as ElastoPlastic, HyperElastic, HyperPlastic, HyperViscoElastic, HyperViscoPlastic and so on. The hierarchical structure, the association relationships as well as key attributes and methods of these classes are presented. We used a C++ implementation of the above model for developing HyperElastic, HyperElastoPlastic and Contact applications in the Diffpack environment. More >