Anisotropic constitutive modeling with the considerations of two strategies in describing the distorted hardening of AA6061 under tension-dominated loading conditions

This paper investigates the anisotropic yielding and distorted hardening behaviors of AA6061-T6. Yoon 2014 model was used to describe the anisotropic plastic behaviors of material and two strategies (i.e. different equivalent plastic strain intervals at two levels) in describing the distorted hardening were used. At the integration point level, a program utilizing the forward Euler method and regression mapping algorithms has been developed. This program accepts strain as input and provides corresponding stress as output. Results found that the prediction ability of constitutive model strongly depend on the strain interval of parameters identification. Excessive interval might result in the unexpected fluctuations of stress-strain curve. Such fluctuations primarily come from the deviation of identified parameters and interpolation data. The former deviation is found caused by the changes in initial value during identifying and the latter mainly because the interpolation data departures from the actual values. In addition, a detailed analysis about parameters effects is also conducted for in-depth understanding of parameters identification.