Fracture Behavior and Mechanism of Ceramic Fiber Insulation Tiles: An Analysis Based on Experiment and Numerical Simulation

Ceramic fiber insulation tile (CFIT) is a brittle porous ceramic fiber material. Its three-dimensional random network structure yields low density, high porosity, low thermal conductivity, and excellent high-temperature stability, making it a widely used material in aerospace thermal protection systems. This renders it particularly crucial to explore fracture dimensions, improve the fracture toughness of materials, and circumvent internal defects. In this study, the numerical simulation and experimental approaches are employed to investigate the fracture behavior and toughening mechanism of CFIT. First, a three-dimensional network model and macroscopic finite element (FE) model of CFIT are established, and the validity of the macroscopic FE model is confirmed by comparison with fracture experimental results. Meanwhile, the effects of CFIT porosity, fiber length, fiber diameter, and fiber orientation angle on fracture toughness are systematically investigated. Furthermore, based on practical requirements, the dimensions and structure of the ceramic fibers are determined, thereby elucidating the mechanism through which changes in crack size influence fracture behavior. Finally, fracture behavior under the macroscopic model is analyzed by introducing different crack sizes and prefabricated defects, and the influence laws of crack size and prefabricated defects on CFIT are determined. In summary, this study provides theoretical guidance for research on the fracture behavior of porous ceramic fiber materials.