Y.C. Shiah¹, Y.C. Lin¹, C. L. Tan²

CMES-Computer Modeling in Engineering & Sciences, Vol.16, No.1, pp. 15-26, 2006, DOI:10.3970/cmes.2006.016.015

Abstract In this paper, the order of singularity of the integrals appearing in the boundary integral equation for two-dimensional BEM analysis in anisotropic elasticity is reduced using integration by parts. The integral containing the traction fundamental solution is then analytically integrated to give an exact formulation for a general element of n-order interpolation of the variables. This allows the integrals to be very accurately evaluated even for very thin, slender bodies without the need for excessively refined meshes as in conventional BEM analysis. Three example problems involving thin, layered materials are presented to demonstrate the veracity and More >

B. Yang², V. K. Tewary³

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.3, pp. 165-178, 2006, DOI:10.3970/cmes.2006.015.165

Abstract Green's function (GF) modeling of defects may take effect only if the GF as well as its various integrals over a line, a surface and/or a volume can be efficiently evaluated. The GF is needed in modeling a point defect, while integrals are needed in modeling line, surface and volumetric defects. In a matrix of multilayered, generally anisotropic and linearly elastic and piezoelectric materials, the GF has been derived by applying 2D Fourier transforms and the Stroh formalism. Its use involves another two dimensions of integration in the Fourier inverse transform. A semi-analytical scheme has… More >

P.D. Shah¹, C.L. Tan^1,2, X. Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.13, No.3, pp. 185-198, 2006, DOI:10.3970/cmes.2006.013.185

Abstract In this paper, the path independent mutual or M-integral for the computation of the T-stress for interface cracks between dissimilar anisotropic, linear elastic solids, is developed. The required auxiliary field solution is derived from the solution of the problem of an anisotropic composite wedge subjected to a point force at its apex. The Boundary Element Method (BEM) is employed for the numerical stress analysis in which special crack-tip elements with the proper oscillatory traction singularity are used. The successful implementation of the procedure for evaluating the T-stress in a bi-material interface crack and its application are demonstrated More >

J. Sladek¹, V. Sladek, Ch.Zhang²

Structural Durability & Health Monitoring, Vol.1, No.2, pp. 131-144, 2005, DOI:10.3970/sdhm.2005.001.131

Abstract A meshless method based on the local Petrov-Galerkin approach is proposed for crack analysis in two-dimensional (2-d), anisotropic and linear elastic solids with continuously varying material properties. Both quasi-static and transient elastodynamic problems are considered. For time-dependent problems, the Laplace-transform technique is utilized. A unit step function is used as the test function in the local weak-form. It is leading to local boundary integral equations (LBIEs) involving only a domain-integral in the case of transient dynamic problems. The analyzed domain is divided into small subdomains with a circular shape. The moving least-squares (MLS) method is More >

Y.C. Shiah¹, T.L. Guao¹, C.L. Tan²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.3, pp. 321-338, 2005, DOI:10.3970/cmes.2005.007.321

Abstract It is well known in elastic stress analysis using the boundary element method (BEM) that an additional volume integral appears in the basic form of the boundary integral equation if thermal effects are considered. In order to restore this general numerical tool as a truly boundary solution technique, it is perhaps most desirable to transform this volume integral exactly into boundary ones. For general 2D anisotropic thermo-elastostatics without heat sources, this was only achieved very recently. The presence of concentrated heat sources in the domain, however, leads to singularities at these points that pose additional More >

J. Sladek¹, V. Sladek¹, S.N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.5, pp. 477-490, 2004, DOI:10.3970/cmes.2004.006.477

Abstract A meshless method based on the local Petrov-Galerkin approach is proposed for solution of static and elastodynamic problems in a homogeneous anisotropic medium. The Heaviside step function is used as the test functions in the local weak form. It is leading to derive local boundary integral equations (LBIEs). For transient elastodynamic problems the Laplace transfor technique is applied and the LBIEs are given in the Laplace transform domain. The analyzed domain is covered by small subdomains with a simple geometry such as circles in 2-d problems. The final form of local integral equations has a More >

K. Woo¹, H. Igawa², C.H. Jenkins³

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 397-408, 2004, DOI:10.3970/cmes.2004.006.397

Abstract This paper presents the development and evaluation of a wrinkling analysis procedure for anisotropic membranes. The procedure is based on a penalty-parameter modified material model and a non-linear root finding to simulate the uni-axial stress state. The procedure was implemented in the ABAQUS finite element code as a user subroutine, and then applied to annular and square membranes. The wrinkle problems were also solved by shell element post-buckling analysis and the results were compared. The effect of anisotropy and unsymmetric loading on the wrinkling behavior was investigated. More >

J. Sladek¹, V. Sladek¹, S.N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.3, pp. 309-318, 2004, DOI:10.3970/cmes.2004.006.309

Abstract Meshless methods based on the local Petrov-Galerkin approach are proposed for solution of steady and transient heat conduction problem in a continuously nonhomogeneous anisotropic medium. Fundamental solution of the governing partial differential equations and the Heaviside step function are used as the test functions in the local weak form. It is leading to derive local boundary integral equations which are given in the Laplace transform domain. The analyzed domain is covered by small subdomains with a simple geometry. To eliminate the number of unknowns on artificial boundaries of subdomains the modified fundamental solution and/or the More >

P. Vena¹, R. Contro

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 497-506, 2003, DOI:10.3970/cmes.2003.004.497

Abstract The adoption of artificial ligaments in current surgery is still characterised by a low success rate due to the fact that mechanical properties of the biomedical devices are such that a biomechanical compatibility is not fully satisfied. A durable artificial ligament should exhibit stiffness as well as strength properties which are such that a full articulation functionality is guaranteed. To this purpose, reliable numerical methods able to predict the mechanical behaviour of such devices both in the elastic and in inelastic range until complete rupture, could be used for designing of devices with tailored mechanical More >

Wolfgang Brocks¹, Weidong Qi²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.3, pp. 313-320, 2002, DOI:10.3970/cmes.2002.003.313

Abstract Results of a numerical study of creep damage development and its effect on the deformation behavior in the Ni-based superalloy IN 738 LC at 850 °C are reported. A continuum damage mechanics based anisotropic damage model has been coupled with the unified model of Chaboche, and is used for the present study. Numerical computations are performed on a plate containing a circular hole under tension. They show that the applied damage model does not cause damage localization and no significant mesh-dependence of the results are observed. More >