Monday  |  Salon 10  |  09:20 AM–09:40 AM

#15662, Determining the Yoshida-Uemori Combined Isotropic/Kinematic Hardening Model Parameters from Tension-Compression Tests of Sheet Metals

Automotive sheet metal forming often includes bend/unbend processes as the material is pulled through draw beads into the die. To properly model these processes, a constitutive law that can capture combined isotropic/kinematic hardening and knowledge of the materials response to both in-plane tension and in-plane compression are required. One such constitutive model that is widely used is the Yoshida-Uemori (Y-U) model. This model must be calibrated for both the tension-compression cycles of the material response. In this work, uniaxial tension-compression experiments with anti-buckling guides were used to develop the needed stress-strain data for four sheet metals (two aluminum alloys and two advanced high strength steels). The Y-U model parameters were determined from these data by optimization methods and a traditional manual method. The parameter sets determined by each method were compared based on the model's ability to capture the measured curves for three repeat tests. The results were quantitatively assessed using the residual between the measured and computed curves. The results show that optimizing the parameters with a finite element model, rather than the manual method, should be used to determine the Y-U parameters, since those parameter sets for the Y-U constitutive model will be eventually used in a finite element model to simulate a forming process. The need to use the optimization method was especially true when determining a single set of parameters for repeat tests.

Mark Iadicola   NIST
Dilip Banerjee   NIST
William Luecke   NIST
Evan Rust   NIST