Constitutive Properties of Silicone- Impregnated Reusable Ceramic Ablator in Compression: Poisson's Ratios

摘要

Measurements were made of the two intrinsic Young moduli E_T and E_P and the three Poisson ratios v_(23), v_(21), and v_(12) of silicone-impregnated reusable ceramic ablator. The average numerical values of the Poisson ratios were v_(23) = 0.27 ± 0.025, v_(21) = 0.14 ± 0.030, and v_(12) = 0.05 ± 0.014, where the ± values are 1 standard deviation. The results are in reasonably good agreement with the theoretical relation v_(21)/E_P = v_(12)/E_T for transversely isotropic materials. Additionally, a model for describing the influence of SIRCA's soft surface layer upon the compressive response was generalized to account for cases in which the Young modulus does not vanish at the surface.