A constitutive model for In situ comminuted silicon carbide

Cylindrical hot-pressed silicon carbide (SiC) ceramic targets were predamaged before ballistic testing. The SiC was thermally shocked to introduce noncontiguous cracks, then additional damage was induced by load-unload cycling in an MTS machine while the ceramic specimen was confined in a 7075-T6 aluminum sleeve. Long gold rod penetration was measured as a function of impact velocity nu(P) over the approximate range of 1-3 km/s, with most data between 1.5 and 3 km/s. Penetration as a function of time was measured using multiple, independently timed flash X-rays. It was assumed that the penetration response of the damaged SiC could be represented by a Drucker-Prager constitutive model. Numerical simulations were used to estimate the constitutive constants. It was found that simulations could not be used to determine a unique set of constitutive constants within experimental data scatter.