Predictive Tool for Aging Effects on Performance of Phenolic-Based Thermal Protection Materials

Hypersonic weapons and aerospace vehicles experience extreme thermo-mechanical loads, which has required the development of novel material solutions to better protect sensitive internal components from these. A strategy for one-time use scenarios is a class of materials that ablate or chemically react and transform into gases under extreme thermal loads. Carbon phenolic ablators are advanced composite ablators that have found growing usage, spurring an industry need for accurate and appropriate material models. Ablative phenolic carbon is vulnerable to a number of aging phenomena due to the chemically-organic nature of phenolic resin. Coupled with the wide variety of microstructures and chemistries in ablative phenolic carbon composites, the ability to predict actual material responses in real world scenarios is greatly diminished. In response to the Navy's need to predict the effects of aging on the ablative response of phenolic composites, Corvid Technologies proposes development of a material model plugin to the CHarring Ablator Response code (CHAR), the National Aeronautics and Space Administration’s (NASA’s) state-of-the-art ablation code. This proposed plugin can be used to modify the underlying material property inputs for phenolic carbon composites of a given microstructure and chemistry as a function of aging mechanism and time. Corvid will develop the CHAR aging material model plugin using a multiple-length-scale modeling and simulation approach which will handshake chemistry affects from the atomistic scale with Molecular Dynamics to the microstructural evolution as a function of time at the meso-scale with Phase-Field Modeling. The results will be homogenized into long-time scale trends that will be able to forecast the material effects of aging up to 60 years. Once developed, the end product will be a fast calculation tool capable of applying effects of multiple aging mechanisms simultaneously to estimate current material properties and response. Current approaches do not account for aging when simulating ablative response, and while there are a few experimental investigations into accelerated aging effects, the effect of long-time scales (i.e. greater than 3 years) on ablative behavior is currently unknown. Corvid will leverage our extensive multi-length-scale material modeling expertise and massively-parallel high-performance computing (HPC) system to bridge both time and length scales to deliver a model that can account for the diverse array of composite microstructures and chemistries of phenolic-carbon composites, as well as the specific effects of multiple aging mechanisms on those composite microstructural features.