Stress Wave Propagation in an RTV Rubber

Abstract

The response of a “rubbery” polymer, Dow Corning Silastic J Mold Making Silicone Rubber, to high-amplitude, short-duration loading is studied using acoustic waves and high-amplitude stress waves. The acoustic experiments measured the phase velocity of a 1 MHz wave over a temperature range of −30°C to +65°C. These measurements were used to deduce the zero-strain slope of the instantaneous and equilibrium stress-strain curves for this material. Flyer-plate impact experiments were used to study the high-amplitude response. Two instrumentation techniques were used in this phase of the study. The first employed a quartz gauge in the “direct-impact” configuration to obtain information about the equilibrium stress-strain curve. The second employed velocity interferometer techniques to observed transmitted wave profiles and thereby obtain information about both the instantaneous and equilibrium curves. From these data, stress-strain curves were determined for the Silastic J up to 0.8 GPa. Using this material characterization, the transmitted wave experiments were simulated using a one-dimensional wave propagation code. The results of the calculations compare favorably with the transmitted wave profiles observed in the actual experiments.