Establishment and Application of an Elastic-Plastic Damage Constitutive Model for Ceramic Fiber Insulation Tiles

A thermal protection system is critical for ensuring the safe take-off and return of various aircraft. A key heat-resistant material within this system is the ceramic fiber insulation tile (CFIT), which is a porous three-dimensional network material with density ranges from 0.3 to 0.4 g/cm³ that exhibits complex mechanical behaviors. Due to the complexity of the service environment, experimental methods cannot accurately capture the mechanical behavior of a CFIT. Although simulation-based methods can provide insights, an accurate constitutive model for CFITs has yet to be established. To predict its complex mechanical behavior, an elastic-plastic damage constitutive model was established for CFITs. Based on the Hashin criteria and four fundamental assumptions, a yield rule was modified by introducing a damage factor in the TTT direction. The model was encoded into a user-material subroutine (UAMT) integrated within ABAQUS to capture the mechanical responses under four typical working conditions. The change trend of the simulation curve closely aligned with that of the experiment curve, better characterizing the stress-strain relationship of the CFIT under different working conditions such as compression, tension, and shear and the error was less than 18%. The proposed approach was validated by designing a millimeter-level indentation experiment. The results in this paper demonstrate that the maximum loading depths of the simulation and experiment were consistent, and the relative errors were within 12%, respectively. The research provides a reliable elastic-plastic damage constitutive model to predict the mechanical behavior of CFITs under complex working conditions.