Development of a Material Response Model for Carbon/Polysiloxane Ablative

This paper describes the development and validation of a materials response (MR) model of a novel carbon fiber-reinforced polysiloxane (UHTR) composite using NASA Ames’ One-Dimensional Fully Implicit Ablation and Thermal Response Program (1dFIAT). Thermophysical properties of the C/UHTR composite were characterized at elevated temperatures. B-prime tables were constructed using the Aerothermal Chemical Equilibrium (ACE) program. The experimental data used for validation of the MR model were acquired by evaluating the material on an oxyacetylene test bed (OTB) at three heat fluxes: 500, 1000, and 1500 W/cm2 for a 60-second duration. During these aerothermal ablation tests, the back face temperature was monitored using ultrafine K-type thermocouples (0.5 mm diameter) fixed to the back surface. The front face surface temperature was tracked using a two-color infrared (IR) pyrometer. Mass loss and recession data were obtained by measuring the pre- and post-test mass and thickness. These experimental data were compared against the 1dFIAT simulation to validate the MR model.