Article

# Combined parametric quadratic programming and precise integration method based dynamic analysis of elastic-plastic hardening/softening Problems

(Impact Factor: 0.89). 12/2002; 18(6):638-648. DOI: 10.1007/BF02487966

ABSTRACT

The objective of the paper is to develop a new algorithm for numerical solution of dynamic elastic-plastic strain hardening/softening
problems. The gradient dependent model is adopted in the numerical model to overcome the result mesh-sensitivity problem in
the dynamic strain softening or strain localization analysis. The equations for the dynamic elastic-plastic problems are derived
in terms of the parametric variational principle, which is valid for associated, non-associated and strain softening plastic
constitutive models in the finite element analysis. The precise integration method, which has been widely used for discretization
in time domain of the linear problems, is introduced for the solution of dynamic nonlinear equations. The new algorithm proposed
is based on the combination of the parametric quadratic programming method and the precise integration method and has all
the advantages in both of the algorithms. Results of numerical examples demonstrate not only the validity, but also the advantages
of the algorithm proposed for the numerical solution of nonlinear dynamic problems.

### Full-text preview

Available from: ams.cstam.org.cn
• Source
##### Article: An improved mathematical programming method for wrinkling prediction of cloths
[Hide abstract]
ABSTRACT: Purpose – An improved mathematical programming method for numerical simulation of cloth wrinkling is investigated. Design/methodology/approach – Cloth is modeled as the network of bars (called bar network) or membrane elements with a special nonlinear mechanical constitutive law in the finite element analysis. Findings – Compared with conventional numerical methods, the proposed method does not depend on stress iteration, but on the base exchanges in the solution of a standard quadratic programming problem. Thus, the new method presents very good convergence behavior and accurate predictions of wrinkling patterns and stress distributions of cloths. Numerical results demonstrate the validity and the efficiency of the proposed method. Originality/value – From the engineering point of view, accurate numerical methods are required in wrinkling analysis of cloth deformation. The algorithm developed here also can be applied into fields such as large deformation under wind load and dynamic behaviors of cloths.
Full-text · Article · Feb 2005 · International Journal of Clothing Science and Technology
• Source
##### Article: Quadrilateral isoparametric finite elements for plane elastic Cosserat bodies
[Hide abstract]
ABSTRACT: 4-node, 8-node and 8(4)-node quadrilateral plane isoparametric elements are used for the solution of boundary value problems in linear isotropic Cosserat elasticity. The patch test is applied to validate the finite elements. Engineering problems of stress concentration around a circular hole in plane strain condition and mechanical behaviors of heterogeneous materials with rigid inclusions and pores are computed to test the accuracy and capability of these three types of finite elements.
Full-text · Article · Jul 2005 · Acta Mechanica Sinica
• ##### Article: Influence of wall slip on the hydrodynamic behavior of a two-dimensional slider bearing
[Hide abstract]
ABSTRACT: In the present paper, a multi-linearity method is used to address the nonlinear slip control equation for the hydrodynamic analysis of a two-dimensional (2-D) slip gap flow. Numerical analysis of a finite length slider bearing with wall slip shows that the surface limiting shear stress exerts complicated influences on the hydrodynamic behavior of the gap flow. If the slip occurs at either the stationary surface or the moving surface (especially at the stationary surface), there is a transition point in the initial limiting shear stress for the proportional coefficient to affect the hydrodynamic load support in two opposite ways: it increases the hydrodynamic load support at higher initial limiting shear stresses, but decreases the hydrodynamic load support at lower initial limiting shear stresses. If the slip occurs at the moving surface only, no fluid pressure is generated in the case of null initial limiting shear stress. If the slip occurs at both the surfaces with the same slip property, the hydrodynamic load support goes off after a critical sliding speed is reached. A small initial limiting shear stress and a small proportionality coefficient always give rise to a low friction drag.
No preview · Article · Dec 2007 · Acta Mechanica Sinica