High-pressure constitutive response of filled and unfilled silicones*

Shear strength under dynamic compression loading has been measured for a range of silicone materials. Pressure-shear plate impact (PSPI) tests revealed that microfiller content had a modest effect on strength. Like prior particle tracking data, strain-rate sensitivity was found to be negligible. Unlike filler content and strain rate, pressure exerted a large effect on flow strength, as has been previously observed for other polymers. Finite element simulations and Bayesian regression permitted a strength model to be calibrated directly against the measured PSPI target velocities. This approach bypasses the usual PSPI analysis assumptions, which loosens the requirements for test validity, along with providing uncertainty measures. The result is a simple model which can be applied to a range of silicones with relatively well characterized uncertainty.