David Degenhardt develops an elasto-viscoplastic material model in order
to predict the temperature and strain rate-dependent deformation and
fracture behavior of thermoplastic polymers. The model bases on three
supporting ambient temperatures, where a thermoplastic polymer has been
characterized profoundly at the stress states 1) uni-axial tension and
compression, 2) bi-axial tension and 3) shear. The core of the material
model builds a pressure-dependent yield function with a non-associated
flow rule. Further, it contains an analytical hardening law and a strain
rate-dependent fracture criterion. The model is validated with
components subjected to impact loading at different ambient
temperatures. The comparison of the simulation and the experiments shows
that stiffness, hardening, fractures strain as well as thicknesses can
be well captured.
About the Author:
David Degenhardt is a calculation engineer in the chassis
development department of a German automobile manufacturer and earned
his doctorate while working at the Technische Universität
Carolo-Wilhelmina zu Braunschweig, Germany.