FEM analysis of the biaxial cyclic loading of the elastoplastic plate with concentrators: asymptotic states

Abstract

Elements of structures which work in real conditions quite often are affected by variable temperatures and loadings. Nowadays due to the growth of interest to the knowledge of asymptotic behavior of the inelastic structure subjected to cyclic loading, direct and incremental methods of stabilized state determining begin to develop. If loadings vary and the body deforms elastically, then its durability is defined by fatigue characteristics of material, failure comes after a large number of cycles. If the body experiences elasto-plastic deformation, at loadings below limit, achievement of a dangerous state at rather small number of cycles is possible. In the present study results of finite-element (FEM) calculations of the asymptotical behavior of an elastoplastic plate with the central circular and elliptic holes under the biaxial cyclic loading for three different materials are presented. Incremental cyclic loading of the sample with stress concentrator (the central hole) is performed in the multifunctional finite-element package SIMULIA Abaqus. The ranges of loads found for shakedown, cyclic plasticity, ratcheting are presented. The results obtained are generalized and analyzed. Convenient normalization is suggested. The chosen normalization allows us to present all computed results, corresponding to separate materials, within one common curve with minimum scattering of the points. Convenience of the generalized diagram consists in a possibility to find an asymptotical behavior of an inelastic structure for materials for which computer calculations were not made should be included.