Modeling thermo-oxidation in high temperature polymer matrix composites

The growth of oxidation layers in high temperature polymeric matrix composites is anisotropic (predominant along the axis of the fibers) and inhomogeneous. In this analysis, we study the oxidative layer growth due to long-term aging at high temperatures at the lamina scale. Analyses are carried out using three-dimensional finite element analysis of repeated volume elements representing the fiber, matrix and interphase regions and the resin oxidation model developed earlier. Although the finite element model is capable of analyzing multiple phases under thermo-oxidation, only resin oxidation is considered and fiber is assumed inert. The paper presents parametric studies illustrating the anisotropy in the oxidative region growth and the effect of fiber diffusivity on the oxidation layer growth rates.