Predictive Material Response Model and Aerothermal Ablation Testing to Investigate Aging Phenolic-based Abative Performance

The innovation of this “Predictive Tool for Aging Effects on Performance of Phenolic-Based Thermal Protective Materials” proposal involves the development of accelerated heating rates combined with multiple years of aging using TGA and dTGA methodology. Similar accelerated heating conditions of carbon/phenolic (C/Ph) panels in a high temperature oven for comparison of mechanical property determination, such as tensile modulus, compression, and ILSS determinations of the TGA and oven treated samples will be carried out. A set of fully characterized C/Ph material properties, control, and aged samples will provide numerical values by varying k and Cp values or other thermophysical properties. Those values will be used for material response modeling using 1dITRAC and 1dFIAT codes or CMA code from Navy. Aerothermal ablation testing approach using Oxy-acetylene Test Bed (OTB) test data with 500, 1000, and 1500 W/cm2 for 60 s to determine surface temperature, in-situ recession rate, in-depth temperatures, and backside heat-soaked temperatures. This will result in a set of empirical data vs. multiple years aged C/Ph samples for trend/correlation of aging vs. reduced ablation performance for material response modeling with 1dITRAC and 1dFIAT codes or Navy CMA code. In conjunction with accelerated TGA methodology and accelerated oven aged C/Ph material as well as OTB aerothermal ablation testing with heat fluxes of 500, 1000, and 1500 W/cm2 for 60 s with the KAI OTB, aged C/Ph samples will be viewed for voids. Using SEM for voids and synchrotron hard X-ray µ-CT Beamline 8.3.2 at Lawrence Berkeley National Laboratory/Advanced Light Source (LBNL/ALS) for 3D images of aged C/Ph will be examined. The 3D images will review the presence of and changes in voids and whether voids are interlaminar or intralaminar within the C/Ph panels. It is anticipated that accelerated thermal aging and OTB testing of aged C/Ph panels using 1dITRAC and 1dFIAT codes or Navy CMA code will result in a novel tool to predict performance due to aging effects, such as service life of thermal protective materials.