Deformation Failure Mechanisms and Post-Impact Thermal Insulation of Density-Graded Polyimide Aerogels Subjected to Axial Quasi-Static Compression and Low-Velocity Impact

. In addition, the high-density regions of gradient PI aerogels retain excellent thermal insulation performance after impact. This study elucidates the critical role of density gradient direction and layer configuration in regulating the mechanical and thermal performances of PI aerogels. The findings provide mechanistic insights for the rational design of gradient PI aerogel-based protective structures requiring balanced lightweight, energy absorption, and thermal insulation under static and dynamic loading conditions.