Extension of the modified Mohr-Coulomb fracture model by a strain rate and temperature dependence

Abstract

Abstract. During industrial sheet metal processes such as shear cutting, high temperatures and strain rates occur. Due to materials dependency on temperature and strain rate, the numerical fracture modelling should consider these both highly influential factors for accurate simulation results. Since the widely used Modified Mohr-Coulomb (MMC) fracture model does not take the dependency on temperature and strain rate into account, the objective of this research is therefore to extend the MMC fracture model. For the fracture characterization, miniaturised tensile tests under variation of specimen geometry, temperature and strain rate are conducted. Additionally, tensile tests with butterfly specimens under varying stress states are carried out. In order to determine material specific MMC parameters, the experimental tests are numerically depicted in Abaqus. The temperature and strain rate extension of the MMC fracture model is based on the Johnson-Cook failure model. With this approach, a temperature and strain-rate dependent MMC fracture model is developed for the dual phase steel DP980.