Continuum damage modeling for ductile metals under high strain rate deformation

The accuracy of the computational investigation on the response of ductile materials under dynamic condition depends on the capability of the constitutive model in accounting for strain rate, temperature and microstructural effects. In this work, we propose a damage evolution law, valid for a wide range of strain rates, based on the theory of continuum damage mechanics (CDM). This model implicitly accounts for the three stages of damage: the nucleation, the growth and the coalescence. This non-linear isotropic CDM model for ductile damage is developed by assuming the existence of a new ductile damage dissipation potential. The proposed damage law is coupled with an evolution law for the flow stress. Like in the mechanical threshold stress (M.T.S.) model, the flow stress is decomposed as the sum of an athennal component and a temperature and strain rate dependent component. Results from our model are in agreement with the existing experimental results for stress-strain behavior and damage evolution in oxygen-free high-conducting (OFHC) copper under both quasi-static and dynamic loading conditions.