Damage quantification and experimental simulation of momentum trapped flyer plate and tensile split Hopkinson bar incipient failure experiments

Abstract
Dynamic and quasi-static failure and dynamic incipient failure experiments were performed on a halfhard 10100 Cu material using several different specimen geometries, including uniaxial stress and several notches. An additional series of uniaxial strain incipient failure experiments were performed using the annealed material. Damage quantification of the incipient failure specimens was performed and statistically reduced for comparison with continuum damage model predictions from explicit simulations of the experiments. Experimentally the test to test variability of the dynamic strain and flow stress measurements greatly exceeded that of the quasi-static measurements. Only the experiments with dynamic strain measurements close to post-test sample measurements were simulated. The ability of the simulations and the dynamic stress-strain measurements to detect the damage induced softening is low, at least until the damage coalesces into a crack. The damage model predictions ofporosity evolution are within a factor of two for two experiments that differ in strain rate and stress triaxiality by over an order of magnitude.