Mechanical property changes in CFRP and structural integrity of rocket motor casings under thermal aging

This paper presents a comprehensive investigation into the impact of thermal aging on the mechanical performance and load-carrying capacity of carbon fiber reinforced polymer (CFRP) composites employed in solid rocket motor casings. The tensile and shear properties of CFRP laminates were evaluated through thermal aging experiments conducted over 720 hours at a temperature of 120°C. A finite element model of the casing was developed in ABAQUS, simulating damage evolution and failure behavior under internal pressure utilizing progressive damage theory. The findings indicate that thermal aging significantly diminishes the transverse and shear properties, with reductions of up to 30.2% and 16.2%, respectively. Matrix degradation and interlaminar damage due to thermal aging are critical mechanisms contributing to the performance degradation of the material. Numerical simulations reveal a 5.6% decrease in the bursting pressure of the thermally aged casing, with the failure mode predominantly characterized by fiber tensile damage, particularly in the shoulder and transition sections. These insights offer valuable guidance for the structural design and optimization of CFRP composites in high-temperature environments.