Determination of the dynamic strain hardening parameters from acceleration fields

The aim of the present study is to determine dynamic strain hardening parameters accurately using an inverse method so that accurate hardening properties at intermediate or high strain rates can be provided for automotive crash analysis simulations. In order to validate the identification procedure, a proper constitutive model was selected and a finite element (FE) analysis was carried out to obtain simulated measurements. The same identification procedure as that which will be implemented in the experiments was adopted. The virtual fields method (VFM) was used as an inverse method to retrieve the constitutive parameters. Since precise measurement of the applied force is not an easy task at high strain rates due to the inertial effect, the identification was performed without using the force information. Instead, the acceleration fields were used for the identification. The obtained parameters using the VFM were compared with the reference ones, which were fed into the FE simulations and very promising results were acquired from the VFM. In addition, a novel high speed tensile tester for sheet metal specimens was developed to validate the proposed methodology in the experiments.11sciescopu