Inverse identification of the post-necking work hardening behaviour of thick HSS through full-field strain measurements during diffuse necking

Abstract

A procedure is presented to identify the post-necking work hardening behaviour of thick HSS steels using a standard uniaxial tensile machine. The pre-necking strain hardening behaviour is available from standard quasi-static tensile tests in the rolling direction. The method is extended beyond necking by performing an inverse identification using the Finite Element Model Update technique and the heterogeneously. A synchronized Digital Image Correlation setup is employed to acquire experimental full-field strain fields at the surface of the diffuse neck and inversely identify the strain hardening behaviour beyond the point of maximum uniform strain. Double notched tensile specimens are used to inversely identify the 3D plastic anisotropy. Subsequently, the effect of plastic anisotropy on the identified post-necking work hardening behaviour is scrutinized. Finally, the robustness of the proposed procedure to identify post-necking strain hardening behaviour is experimentally assessed.