A Full-Field Calibration Based on DIC for Parameter Identification of 3rd Gen AHSS

Accurate material characterization is important to structural analysis. To obtain better prediction accuracy, complex material constitutive models are used widely, resulting the requirement of more test data for parameter identification. DIC (Digital Image Correlation) becomes more and more popular, providing full-field strain history with an optical method that could not be obtained by conventional test methods. This paper compared the full-field calibration (FFC) of 3rd generation AHSS QP980 based on DIC data and the traditional curve matching calibration (CMC) based on force-displacement data using LS-OPT. Barlat89 yield criterion and combined Swift and Hockett-Sherby hardening model were used to better characterize the anisotropy and hardening behavior of QP980 material. The standard uniaxial tensile, R5, R20 and R80 notched tensile tests were carried out to calibrate all needed parameters. In terms of the force-displacement curve, the difference between FFC and CMC is small, with a deviation of 8.9%. On the other hand, in terms of strain field, the difference is significantly different. Compared with CMC, max error of local strain decreases 41% in FFC. Simulated result of FFC correlates better to experiment than that of CMC.