CORRELATIONS OF COMPUTED SIMULATIONS WITH RESIDUAL HARDNESS MAPPINGS AND MICROSTRUCTURAL OBSERVATIONS OF HIGH-VELOCITY AND HYPERVELOCITY IMPACT CRATERS IN COPPER

An AUTODYN 2D (version 3.0), PC-compatible hydrocode utilizing Lagrang ian and Eulerian processors (the latter including a fracture criterion ) with a Johnson-Cook constitutive relationship has been applied to si mulating experimentally developed impact craters in 1.3 cm thick OFHC copper targets for 1100 aluminium spheres (nominally 3.2 mm diameter) impacting at velocities ranging from 1.08 to 6.01 km/s. Good validatio n was achieved not only for crater dimensions but especially for the s imulation of crater shapes and other features - including fractured or particulated crater rims. target spallation at 4.4 and 6.01 km/s and residual stress contours extending from the crater wall; which were re lated to residual, experimental hardness profiles and crater-related m icrostructures observed by optical and transmission electron microscop y. This comprehensive validation of 2D hydrocode simulations allowed e xtrapolations for impact craters well into the hypervelocity regime: 1 2 and 24 km/s, where dynamic recrystallization was demonstrated to con tribute significantly to hypervelocity impact crater formation.