Formability for Hot Stamping of Al-Alloy Panel Parts

A coupled thermo-mechanical viscoplastic-damage model for the aluminum alloy AA6082 is developed and determined from experimental data for ranges of temperatures and strain rates. The unified viscoplastic damage constitutive equations are input into the commercial Finite Element code Abaqus/Explicit via the user defined subroutine, VUMAT. An FE process simulation model and numerical procedures are established for the modelling of hot stamping and cold die forming process for a spherical part with a central hole. Different failure modes (failure takes place either near the central hole or in the mid span of the part) are obtained. To validate the simulation results, a test programme is developed, a test rig has been designed and manufactured, and tests have been carried out for the material with different forming rates. It has been found that a very close agreement is observed between the experimental and predicted results.