Open Access
ARTICLE
Wen-Hwa Chen1, Cheng-Hung Chen2
CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 177-190, 2005, DOI:10.3970/cmes.2005.008.177
Abstract An enriched meshless method, using meshless interpolations and a global Galerkin approach, is developed for the analysis of three-dimensional fracture problems. The displacement field which accounts for the stress singularity nearby the crack front and the boundary layer effect at the intersection between the crack front and the free surface of the structure is adopted to enrich the trial functions. The three-dimensional stress intensity factors can thus be treated as independent unknown parameters and calculated with the nodal displacements directly. To estimate the accuracy of the method developed, several representative three-dimensional cracks are analyzed. These include single-edge crack, embedded elliptical… More >
Open Access
ARTICLE
F. Cosmi1
CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 191-200, 2005, DOI:10.3970/cmes.2005.008.191
Abstract The Cell Method is a recently developed numerical method that is giving interesting results in several fields of physics and engineering. In this paper, first a brief description of the method for elasticity problems is given and successively the elastodynamics formulation is derived. The method leads to an explicit solution system, combining the advantages of a diagonal mass matrix and the possibility of using unstructured meshes. The convergence rate has been tested in reference to the problem of free harmonic vibrations in a system with one degree of freedom, showing that the Cell Method has the same convergence rate of… More >
Open Access
ARTICLE
W. J. Ferguson1, B. Palananthakumar2
CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 201-216, 2005, DOI:10.3970/cmes.2005.008.201
Abstract Environmental and safety issues associated with landfill gas require the control of off-site migration. Mathematical modelling can assist in the understanding of the processes and mechanisms controlling gas migration from municipal waste disposal sites. This paper presents the development and application of a mathematical model that simulates landfill gas migration within a partially saturated soil. This model accounts for two-phase flow and incorporates multi-component (methane, carbon dioxide, dry air and moisture) transport in the gas and liquid phases together with concomitant heat migration. The governing system of fully coupled non-linear partial differential equations of the model have been derived from… More >
Open Access
ARTICLE
Aleksandr N. Guz1
CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 217-230, 2005, DOI:10.3970/cmes.2005.008.217
Abstract The ultrasonic non-destructive method of determination of stresses in near-the-surface layers of solid bodies is based on the regularities of elastic surface wave propagation in bodies with initial (residual) stresses. Above mentioned regularities are received in the framework of the 3-D linearized theory of waves propagation in bodies with initial (residual) stresses. Computational methods are used for solution of the dispersion equations as applied to problems under consideration. Description of the non-destructive method and information on instruments and devices for measurements are presented. Some examples of non-destructive determination of stresses in near-the-surface layers of materials are presented also as applied… More >
Open Access
ARTICLE
Chein-Shan Liu1
CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 231-258, 2005, DOI:10.3970/cmes.2005.008.231
Abstract Using a group-theoretical approach in the Minkowski space we explore kinematic hardening rules from a viewpoint of the Poincaré group. The resultant models possess two intrinsic times q0a and q0b; the first q0a controls the on/off switch of plasticity, and the second q0b controls the pace of back stress during plastic deformation. We find that some existent kinematic hardening rules, including the modifications from the Armstrong-Frederick kinematic hardening rule, can be categorized into type I, type II and type III, which correspond respectively to q0b = 0, q0b = q0a and q0b… More >
Open Access
ARTICLE
J. Sladek1, V. Sladek1, J. Krivacek1, Ch. Zhang2
CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 259-270, 2005, DOI:10.3970/cmes.2005.008.259
Abstract A meshless method based on the local Petrov-Galerkin approach is presented for stress analysis in three-dimensional (3-d) axisymmetric linear elastic solids with continuously varying material properties. The inertial effects are considered in dynamic problems. A unit step function is used as the test functions in the local weak-form. It is leading to local boundary integral equations (LBIEs). For transient elastodynamic problems the Laplace-transform technique is applied and the LBIEs are given in the Laplace-transformed domain. Axial symmetry of the geometry and the boundary conditions for a 3-d linear elastic solid reduces the original 3-d boundary value problem into a 2-d… More >