Validation of Novel Nondestructive Method Measuring Char Depth in Ablative Materials

This study presents a novel nondestructive measurement method for quantifying the char depth in composite ablatives subjected to aerothermal testing. Utilizing microstructural analysis, this method achieves measurement performance comparable to that of traditional destructive techniques, with an average measurement deviation of 3%. Assessing pyrolysis reactions in composite ablatives is crucial for evaluating ground- and flight-tested materials without compromising integrity, enhancing understanding of composite behavior, and informing heat shield sizing. Physical measurements were used as a control to validate pyrolysis reactions and char depths, necessitating sample bisection after micro-computed tomography (micro-CT) scans. Microstructural renderings from the micro-CT scans were segmented into virgin and char categories, with the pyrolysis front determined using a deep-learning segmentation model. This research demonstrates that microstructural data obtained through nondestructive micro-CT imaging can accurately quantify pyrolysis in composite ablatives, effectively replacing traditional destructive physical measurements.