U-0.75Ti and Ti-6Al-4V in Planar and Ballistic Impact Experiments.

The response of U and Ti alloys has been studied in planar and ballistic impact experiments performed with a 25 mm light-gas gun. Free surface velocities were monitored by VISAR. The velocity profiles and the damage maps were simulated using 2D AUTODYN™ finite differences code. A modified Steinberg-Cochran-Guinan constitutive model was calibrated by simulating planar impact experiments. Bauschinger effect and a single-parameter spall model were added to describe the unloading and the tensile paths. The ballistic experiments were simulated by using the calibrated model. Softly recovered samples revealed different degrees of spall fracture (planar impact) and of adiabatic shear bands (ballistic experiments). The results demonstrate a possibility to combine experimental and numerical techniques, VISAR and AUTODYN, to calibrate constitutive models of solids in a wide range of shock-induced strain. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]