Donghuan Liu¹, Xiaoping Zheng^1,2, Yinghua Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.3, pp. 263-300, 2009, DOI:10.3970/cmes.2009.039.263

Abstract A discontinuous Galerkin (DG) finite element method for the heat conduction problems with local high gradient and thermal contact resistance is presented. The DG formulation is constructed by employing the stabilization term and the Bassi-Rebay numerical flux term. The stabilization term is defined by a penalization of the temperature jump at the interface. By eliminating the penalization term of the temperature jump in the region of local high gradient and imperfect contact interfaces, the present DG method is applied to solve problems involving local high gradient and thermal contact resistance where the numerical flux is… More >

Raju Sethuraman¹, N.R.Rajesh²

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.1, pp. 67-100, 2009, DOI:10.3970/cmes.2009.039.067

Abstract This paper presents a methodology based on Partition of Unity Finite Element Method (PUFEM) and Pseudo Elastic Analysis for solving material non-linear fracture problems within the scope of total deformation theory of plasticity. Local enrichment base functions are used to represent the asymptotic field near the crack tip and discontinuous field across the crack faces. An iterative linear elastic analysis using PUFEM is carried out for the determination of elastic-plastic crack tip stress fields by treating effective material properties as spatial field variables. The effective material parameters are defined using deformation theory and are updated… More >

D. S. Liu¹, C.Y. Tsai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.1, pp. 29-48, 2009, DOI:10.3970/cmes.2009.039.029

Abstract Utilizing a thin copper substrate for illustration purposes, this study presents a novel numerical method for extracting the thermo-mechanical properties of a thin-film. In the proposed approach, molecular dynamics (MD) simulations are performed to establish the load-displacement response of a thin copper substrate nanoindented at temperatures ranging from 300~1400 K. The load data are then input to an artificial neural network (ANN), trained using a finite element model (FEM), in order to extract the material constants of the copper substrate. The material constants are then used to construct the corresponding stress-strain curve, from which the… More >

Chyanbin Hwu¹, T.L. Kuo, Y.C. Chen

CMC-Computers, Materials & Continua, Vol.11, No.3, pp. 165-184, 2009, DOI:10.3970/cmc.2009.011.165

Abstract In this paper the near tip solutions for interface corners written in terms of the stress intensity factors are presented in a unified expression. This single expression is applicable for any kinds of interface corners including corners and cracks in homogeneous materials as well as interface corners and interface cracks lying between two dissimilar materials, in which the materials can be any kinds of linear elastic anisotropic materials or piezoelectric materials. Through this unified expression of near tip solutions, the singular orders of stresses and their associated stress/electric intensity factors for different kinds of interface 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 More >

G. Savaidis¹, N. Pitatzis¹, A. Savaidis¹, Ch. Zhang²

Structural Durability & Health Monitoring, Vol.4, No.3, pp. 145-160, 2008, DOI:10.3970/sdhm.2008.004.145

Abstract This paper presents an elastic-plastic finite element analysis of a circumferentially notched cylinder subjected to multiaxial non-proportional fatigue loading. Two different load combinations are investigated: (1) constant tension with cyclic torsion and (2) constant torsion with cyclic tension. The multilayer plasticity model of Besseling in conjunction with the von Mises yield criterion is applied to describe the elastic-plastic material behaviour. The parametrical study contains a coarse and a fine finite element mesh with and without mid-nodes as well as three different types of multilinear approximations of the material law, namely, a twenty-segments, a five-segments and More >

G.S. Palani¹, B. Dattaguru², Nagesh R. Iyer¹

Structural Durability & Health Monitoring, Vol.4, No.2, pp. 77-94, 2008, DOI:10.3970/sdhm.2008.004.077

Abstract The objective of this paper is to present a generalized technique called as, numerically integrated Modified Virtual Crack Closure Integral (NI-MVCCI) technique for computation of strain energy release rate (SERR) for 2-D crack problems employing singular finite elements. NI-MVCCI technique is generalized one and the expressions for computing SERR are independent of the finite element employed. Stress intensity factor (SIF) can be computed using the relations between SERR and SIF depending on the assumption of plane stress/strain conditions. NI-MVCCI technique has been demonstrated for 8-noded Serendipity (regular & quarter-point) and 9-noded Lagrangian (regular & quarter-point) More >

F.R. Biglari¹, A. Agahi¹, O. Nikfarjam², B. M. Dariani¹, K. Nikbin³

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 47-52, 2008, DOI:10.3970/sdhm.2008.004.047

Abstract A modified sensitivity analysis has been applied to an elastic-plastic finite element analysis 3D blank design in sheet metal forming. In recent literature, the sensitivity method has successfully been applied to several arbitrary shapes. However, in the present paper the sensitivity coefficients are not considered constant during the analysis. The presented approach computes the new coefficients from the two last iterations. This method can produce an initial blank boundary shape that has any arbitrary flange shape. A cup with uniform flange has been studied in detail and results show a faster solution convergence than the More >

F. R. M. Romlay¹

Structural Durability & Health Monitoring, Vol.4, No.1, pp. 19-28, 2008, DOI:10.3970/sdhm.2008.004.019

Abstract This paper presents a surface contact static stress of a spur gear system combined with dynamic characteristic using transient Finite Element Method (FEM). Traditionally, the static stress analysis is done separately with dynamic properties due to limitation of complex equation and avoiding of error occurred. However, in this paper, static stress information is combined with the dynamic mechanism due to the time consuming during the design and analysis stage. A transient FEM analysis is carried out to formulate and solve large systems of algebraic equations in order to obtain a relationship between the contact parameter… More >

F Gentil¹, RM Natal Jorge^2,3, AJM Ferreira⁴, MPL Parente^2,5, PALS Martins^2,6, E Almeida⁷

The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.4, pp. 145-150, 2008, DOI:10.3970/icces.2008.008.145

Abstract The ear can be divided anatomically, into three parts: external, middle, and inner ear. The eardrum separates the external from the middle ear. The perforation of the eardrum can result in conductive moderate hearing loss. More >