Experiments on Damage and Failure Behavior of Biaxially Loaded Specimens under Non-Proportional Load Paths

Abstract

This paper discusses new experiments with the X0-specimen taken from steel sheets and numerical simulations to investigate the influence of proportional and non-proportional loading on damage and failure processes in the moderate stress state regime. The numerical simulations were based on a phenomenological, thermodynamically consistent anisotropic continuum damage model considering the effect of stress triaxiality and the Lode parameter on damage behavior. The proportional and non-proportional loading histories were compared and analyzed. During the experiments, digital image correlation (DIC) was used to assess strain fields on the surface of the specimens, while scanning electron microscopy allowed for an analysis of fracture surfaces (SEM). Numerical simulations reveal stress distributions and the evolution of stress states during the load path. The findings show the effectiveness of the experimental program for highly ductile metals, the accuracy of the presented continuum model as well as the influence of loading history on damage and failure behavior in steel sheets.