含FGM的涂层结构中热残余应力的分析与优化

本文利用有限元方法和优化理论，对含ＦＧＭ（Ｆｕｎｃｔｉｏｎａｌｌｙ　Ｇｒａｄｅｄ　Ｍａｔｅｒｉａｌｓ）层的热喷涂构件中的残余应力进行了数值分析，并获得了ＦＧＭ内各组份体积含量分布的最优化形式和参数ｐ。同时，我们也研究了喷涂构件的几何形状、涂层及基底的材料性能对于ｐ的影响规 律。在本文的分析中，考虑了基底材料和ＦＧＭ的塑性变形以及其性能对于温度的依赖。本文 的工作将有利于含ＦＧＭ层的热喷涂构件的设计与生产。

SIMULATION AND OPTIMIZATION OF THERMAL RESIDUAL STRESS IN COATING STRUCTURE WITH FUNCTIONALLY GRADED MATERIAL LAYER

An elasto-plastic finite element method is developed to predict the thermal residual stress of thermal spraying coatings with functionally graded material (FGM) layer. The optimized distribution form and parameter p about the volume fractions of various constituents in the FGM are obtained by the first order optimization method in the AL2O3 -Ni model system. The effects of geometry and material behavior on the optimization results are investigated numerically, including the temperature sensitivity of FGM and substrate material. It is found that the optimization of the constituent contents in FGM reduces the magnitude of residual stresses to a large degree. And the maximum residual stresses shun the weakest part of the coating structure by the optimization designing. When the length of specimen, the thickness of FGM layer and the thermal expansion coefficient of the substrate increase, while the distribution parameter p decreases. The results presented in this paper are useful for the design of thermal spraying coatings.