Thermal Analysis For Honeycombed Thermal Protection Systems And Structural Optimization

Owing to the severe flying environment and special flying missions, the performance requirements for the spacecraft thermal protection systems (TPS) are far higher compared to that for an ordinary plane, and the designs have been paid great attention to. This dissertation focuses on thermal analysis and structural optimization of the honeycombed TPS, and the main contents are shown as follows:The integrated load bearing and thermal protection honeycombed TPS is studied in the dissertation. Firstly, on the basis of software ABAQUS, the numerical simulation for the heat conduction of the TPS is implemented, and plate model without heat convection boundary conditions is adopted for approximate calculations. The equivalent conductivities for the honeycombed core-fire resistant material mixed part are obtained through other references, and the error through the most optimal method is about 5% compared to experimental results. Furthermore, different mesh sizes and emissivity are validated to have little influences on results.Then, the thermal stresses of the main load bearing honeycombed panels are analyzed with three-dimensional models and the thermal loads boundary conditions are temperature fields from the heat conduction results. After comparing thermal stresses via different TPS thickness, with and without thermal resistant materials, it can be concluded that the better performances of the TPS, the lower temperature and stress values for the main load bearing structure, and the remarkable influences which temperature fields make on thermal stresses cannot be ignored.Finally, on the basis of multidisciplinary optimization platform Isight, the optimum designs of the integrated structure are obtained through plate model and size optimization, which can satisfy the relevant constraints and achieve the objectives of lightest weight and highest performances on thermal protection respectively. Besides, the thermal stresses of the optimal honeycombed panels are calculated. Results show that:for the lightest weight design, the total mass decreases about 8.79% while the thermal stress changes little. And for the highest performance design, the temperature on reverse surface decreases about 31.86% and the maximum Von Mises stress decreases about 45.57% while the total mass almost remains the same compared to the original structure.