Calibration of Chaboche Combined Hardening Model for Large Strain Range

Abstract

Variable-loading path and large strain are two typical features in multistage plastic forming process. Material’s yield surface expands and translates simultaneously as the loading path changes, leading to certain transient phenomena such as Bauschinger effect. Chaboche combined hardening model is widely used in this kind of simulation due to its capability of characterizing the movement and expansion of yield surface. This study provides a parameter calibration method for Chaboche combined hardening model with 3 back stresses in a large strain range. Uniaxial tension-compression cyclic test with constant strain control was conducted for calibrating the Chaboche model firstly. Meanwhile, the flow curve obtained from uniaxial tension test (UT) associated with Swift extrapolation model were employed to provide the stress-strain relation at large strain level. Then, both theoretical analysis and optimal fitting using NSGA-II were used to determine the parameters in Chaboche model by using the data from the small strain cyclic test and the extrapolated UT curve at large strain simultaneously. The calibration result shows a good match with the experimental and extrapolated data, proving the efficiency of the parameter determination manner put forward in this study.