Modeling the Bauschinger effect for sheet metals. I: Theory
The paper deals with a modeling of the Bauchinger effect based on experimental observations. Tests on some alloys show that the reversal loading curve may not saturate to the monotonic loading curve, leaving a permanent offset in addition to a reduction in subsequent yield stress. The authors state that the following basic requirements must be addressed to model the Bauschinger effect properly: correct nonlinearity of stress-strain loop, reduced elastic limit at reversal straining, and permanent offset for some materials. The authors propose an anisotropic hardening model (ANK) and the offset in the reverse flow based on experimental observations. The offset in the reversal flow stress is viewed as a function of accumulated plastic strain and pre-strain. The authors introduce the superposition of two back-stress vectors which evolve independently. The modified Chaboche model can be derived when one of the back-stress vectors is vanishing. Numerical implementation of Chaboche model and ANK model is outlined. A plastic flow rule is considered for the evolution of plastic deformation. A criterion to decide whether the current loading is a continuation of the initial loading or of reversal loading is necessary in order to realize the consistency of the model. A discussion concerning such kind of criterion will be done in the second part of the paper.
scientific article; zbMATH DE number 1797331