Thermal protection system integrating graded insulation materials and multilayer ceramic matrix composite cellular sandwich panels

Current integrated thermal protection systems (ITPS) are generally devised with single layer metal sandwich panel and uniform insulation material, inevitably leading to limited thermal insulation effect and high risk of buckling failure. By contrast, here, ITPS, which incorporates graded insulation materials and multilayer ceramic matrix composite cellular sandwich panels, is devised to raise both thermal insulation effect and buckling strength. The effective thermal and mechanical properties are theoretically established. Transient heat transfer characteristics are numerically calculated. The results reveal that ITPS with specific graded insulation materials can present lower temperature and better temperature distribution uniformity than those of ITPS filled with uniform insulation material, demonstrating that graded insulation layers can firmly enhance the insulation effect. Besides, the insulation effect of ITPS, in which the densities and thermal conductivities of graded layers are taken arranged from low to high, is much better than those of ITPS which have opposite sequence. Moreover, the buckling strength is demonstrated to be significantly improved through the approach of integrating multilayer sandwich panels. The thermal short effect can be also suppressed, since it is demonstrated that the multilayer sandwich panels in the ITPS can reduce the temperature on bottom facesheet and raise the temperature distribution uniformity.