|The US auto industry spends $600M per year fixing and tweaking forming dies that do not make correct parts. The primary reason that the dies are inaccurate is that the computer models of the dies utilize materials models that are inaccurate. Upon surveying our industrial partners, we determined that a key NIST role in addressing this problem lies in developing new mechanical testing methods and metrology, and also developing a fundamental understanding of the interplay between multiaxial strain behavior and sheet microstructure.||
Springback Cup Test
We have developed a technique where, for the first time, the sheet's stress-strain response can be measured along non-linear multiaxial paths. This provides unique data on how the multiaxial flow surface changes with plastic strain, and this can be used to modify materials models used by industry. Concurrently, we also measure the evolving crystallographic texture of the sheet and the surface roughness, to develop a microstructural understanding of the materials' deformation response.