Optimized Postprocessing Method for Fatigue Life Evaluation of Reusable Rocket Combustion Chambers

This study introduces a tailored postprocessing model for in-depth assessment of critical failure mechanisms within the inner liner of regeneratively cooled combustion chambers in reusable liquid rocket engines (RLREs). The approach integrates ductile and brittle damage using a damage accumulation framework based on methodologies from Bonora et al. (“Identification of the Parameters of a Non-Linear Continuum Damage Mechanics Model for Ductile Failure in Metals,” Journal of Strain Analysis for Engineering Design, Vol. 39, No. 6, 2004, pp. 639–651) and Dufailly and Lemaitre (“Modeling Very Low Cycle Fatigue,” International Journal of Damage Mechanics, Vol. 4, No. 2, 1995, pp. 153–170). By incorporating high-temperature material properties of the copper–chromium–zirconium alloy, the model undergoes validation against experimental data from thermomechanical fatigue tests and detailed thermal–structural finite element analysis. The results demonstrate the model’s robustness in predicting damage progression, pinpointing crack initiation zones, and quantifying ratcheting effects, thereby providing a comprehensive tool for assessing fatigue life across diverse RLRE architectures and enhancing engine reusability.