Study of tailor heat treated blanks using the fourier-series-based VFM

In this work, the Virtual Fields Method (VFM) was used to identify the properties of tailor heat treated (THT) blanks, in terms of different hardening parameters. The spatial variation of the hardening parameters was described using the Fourier series approach. The chosen material is an aluminum alloy 5754 H111 that undergoes a localized heat treatment. From the blank sheet, dog-bone specimens were cut and treated using a laser in the central zone. Tensile tests were performed on the sample using Digital Image Correlation (DIC) to obtain the full-field deformation history. Finally, the F-VFM was applied to identify the spatial distribution of the hardening parameters. In order to compare the results with reference values, further tests were conducted on not treated specimens. Thus, the so-called Fourier-based VFM (F-VFM) was introduced for finite deformation plasticity problems; numerical data are used to validate the inverse approach, and, afterwards, the inverse identification process is applied on experimental data from THT specimens.