Modeling of Porosity Effects in Gas-Filled Composites Using Biot’s Parameter

Modeling of porosity effects on the thermal-chemical decomposition of porous, polymer composites at high temperature is treated analytically for no gas flow and compared with finite element results which permit gas flow. A function is proposed for the variation of Biot’s pressure-stress coupling factor in terms of porosity and a constant which can be determined from experiments. The results show this function adequately describes the coupling factor and that the inclusion of gas flow (permeability) is essential to accurate results.