SOLVING THE ELASTOPLASTIC UNLOADING PROBLEMS OF AN AXISYMMETRICAL BODY WITH ACTUAL MATERIAL HARDENING MODELS BY BEM

This paper presents a boundary element formulation and numerical imple mentation of the elastoplastic unloading problem of an axisymmetric bo dy with an actual material hardening model in which the reverse yield stress does not lie between the kinematic hardening yield stress and t he isotropic hardening yield stress of present plastic theory. Three e lastoplastic unloading stress-strain models of high strength low alloy steel with both strain hardening and Bauschinger effect factor are di scussed. The modified Aitken method is used for the unloading iteratio n process. Comparison of the results of this paper with the data of FE M and experiment is given finally.