单晶涡轮叶片三维晶体取向相关性能分析及优化

采用单晶正交各向异性弹性本构关系,分析了三维晶体取向对单晶涡轮叶片应力分布、蠕变寿命、低周疲劳寿命及叶尖径向位移的影响.结果表明,三维晶体取向对单晶叶片上述性能存在显著影响,且3个取向角之间相互耦合,偏差角对叶片性能的影响随着随机角的方位而变化,随机角对叶片性能的影响也随着偏差角的角度而不同.在此基础上,应用ISIGHT构建了单晶叶片全三维取向优化平台,以蠕变寿命、低周疲劳寿命及叶尖最大径向位移为优化目标,采用邻域培植多目标遗传算法进行了叶片三维取向优化,所得Pareto解聚集在偏差角12°的区域内.选择寿命最长的Pareto解作为最优解,相对于初始强度计算点,蠕变寿命提高6倍,低周疲劳寿命提高37倍,叶尖最大径向位移减小2.5%. 

Crystallographic-orientation-related performance of single crystal turbine blade and optimization design of three-dimensional orientations

Based on orthotropic elasticity constitutive model, the influence of three-dimensional crystallographic orientations on the performance of single crystal turbine blade was analyzed. It was shown that three-dimensional crystallographic orientations obviously affected maximum stress, creep life, low-cycle fatigue life and maximum radial displacement on blade top surface. Moreover, three crystallographic angles coupled together. The influence of the deviation angle or one of the random angles changed with the varying orientations of the other two. The orientations optimization was performed in ISIGHT platform with creep life, low-cycle life and maximum radial displacement on blade top surface set as optimization objectives. The neighborhood cultivation genetic algorithm was used to get the Pareto optimal solution set. All Pareto solutions focused within range of the deviation angle about 12 degrees. The Pareto solution with maximum life was chosen as the optimized solution, so the creep life and low-cycle fatigue life increased up to 6 times and 37 times of the original design point, and the maximum radial displacement on blade top surface reduced by 2.5 percentage, respectively.