Effect of Damage Progression on the Thermal Conductivity of 3D Woven Composite Thermal Protection System Materials

Separate versions of Multiscale Recursive Micromechanics models have been combined to enable predictions of 3D woven composite effective thermal conductivities during progressive damage simulations. This enables the effects of the progressive damage on the 3D woven composite effective thermal conductivity components to be captured. This new capability has been applied to a novel 3D woven composite thermal protection system material wherein the performance is highly dependent on both the thermal and mechanical behavior. The Multiscale Recursive Micromechanics approach enables micromechanics models to call other micromechanics models (or themselves recursively) to consider finer and finer length scales. As such, the multiscale models can explicitly consider the matrix and fibers (filaments) within the tows at one length scale, while also considering the geometry of the woven composite repeating unit cell. At an even lower length scale, the microstructure of the pores present in the composite’s phenolic matrix are also explicitly considered. Results focus on the impact of the progressive damage, which is modeled at this lowest length scale, on the 3D woven composite’s effective thermal conductivity components, along with the local thermal flux fields induced in the microstructures across the length scales.