基于温度及应力约束的功能梯度材料壳热分析*

为了推进功能梯度材料在导弹热防护结构设计中的应用,旨在研究温度和应力约束条件下功能梯度材料板的最佳设计变量。首先研究功能梯度材料物性参数随温度的变化规律,在此基础上探讨陶瓷体积分数指数、弹体厚度及热流密度对热传导温度的影响,分析温度约束下的最佳设计变量;同时,探讨确定热流密度下陶瓷体积分数指数、弹体厚度对功能梯度材料壳热应力的影响,分析热应力约束条件下的最佳设计变量。结果表明,体积分数指数大于5后,增大指数热防护效果不再明显,增大弹体厚度可以降低温度,但也会增加导弹整体质量,在同等量级的热流密度下,设计热防护层时不必使用同种厚度。

Temperature and Stress Dependent Based Analysis of a Functionally Grade Material Shell

The purpose is study the best designable quantity of FGMs based on the constraint of the temperature and thermal stress to promote the application of the functionally graded materials (FGMs) in the structure of the thermal protection of the missile. The relation of the physical properties of FGMs along with temperature was studied firstly. And the impacts of ceramic volume fraction, thickness of missile body and the thermal fluid density on the thermal conduct temperature were discussed. The optimal temperature dependent designable quantity was analyzed. At the same time, the impacts of ceramic volume fraction and thickness of missile body on the thermal conduct temperature under certain thermal fluid density were discussed, and the optimal stress dependent designable quantities were studied. Results indicate that the effect of thermal protection is not obvious when the volume fraction above 5; the temperature tends to decrease when the thickness of the missile body increase; it is not necessary to use the same thickness for the same missile body with the same thermal fluid density.