機械的・熱的負荷を受ける傾斜機能厚肉円筒のき裂端応力拡大係数の緩和のための材料組成分布の最適化

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This study treats the optimization problem of material distributions for minimizing the stress intensity factor of radial edge crack in thick-walled functionally graded material (FGM) circular pipes under thermomechanical loading. Homogenizing the FGM circular pipes by simulating the nonhomogeneity of thermal conductivity by a distribution of equivalent eigentemperature gradient and the nonhomogeneities of Young's modulus and Poisson's ratio by a distribution of equivalent eigenstrain, we present an approximation method to obtain the stress intensity factor for a radial edge crack in the FGM circular pipes. The optimum material distributions for minimizing the stress intensity factor of edge crack are determined using a nonlinear mathematical programming method. Numerical results obtained for a thick-walled TiC/Al_2O_3 FGM circular pipe reveal that it is possible to minimize the stress intensity factor of edge crack by choosing an optimum material distribution profile.
2005-12-25