Abstract: The single circular-arc root fillet of traditional curvic coupling in aero-engine often results in a stress concentration feature. To reduce fillet stress values to acceptable levels，the design method of curvic coupling with double circular-arc root fillet was established. The basic formulas for double circular-arc fillet design were provided. Computed results of the numerical examples indicate that the maximum equivalent (Von-Mises) stress of curvic coupling decreased by 5.5% when the single circular-arc root fillet was replaced by double circular-arc root fillet in curvic structure. Furthermore，a structure optimization design model for curvic coupling was presented，which was based on Spey MK202 stressing standards (EGD-3) and curvic coupling design criterion of Gleason Company. Structural optimization design analysis to curvic coupling was carried out using elitist strategy genetic algorithm. Compared with the original single circular-arc root fillet structure，the maximum equivalent stress of the optimum curvic coupling with double circular-arc root fillet is reduced by 12.3%，and the curvic root stress distribution is more homogenous.

Key words: Curvic coupling；Double circular-arc；Structure design；Finite element method；Optimization；Neural network；Genetic algorithm

摘要： 针对航空发动机圆弧端齿结构齿根单圆弧连接区域存在比较严重的应力集中问题，提出一种圆弧端齿结构齿根双圆弧设计方法，以改善齿根附近的应力集中现象。文中推导建立了双圆弧设计的基本公式，算例对比分析表明双圆弧设计的齿根最大等效应力比单圆弧设计降低了5.5%。在此基础上，根据EGD-3应力标准和格里森圆弧端齿设计准则，建立圆弧端齿结构的优化模型，采用精英保留遗传算法的优化方法对圆弧端齿进行了优化设计分析，优化结果表明双圆弧优化设计的齿根最大等效应力比单圆弧设计降低了12.3%，同时改善了齿根附近的应力分布状态。

关键词: 圆弧端齿；双圆弧；结构设计；有限元；优化；神经网络；遗传算法