Abstract: Taking the shrouded blades in a certain turbofan engine as the investigation object，and considering the nonlinear effect of the contact stiffness and damping between neighbor blades，the effects of designable configuration parameters on constrained modes and vibration response were studied by the combination of Newton-Rapson iteration and multi-harmonic balance method. The results reveal that the shroud position is the key parameter which affects the stiffness and resonance frequency of the blade primarily，and the radial relative position is recommended to be between 55% and 75%，which is beneficial to increase the blade stiffness and to decrease the vibration deformation. The axial position is suggested to be in the middle of the blade，in order to increase the contact stiffness of the shroud and the first order resonance frequency of the blade. The shroud coupling angle and initial interference value affect the resonance stress value chiefly，but have little effects on the resonance frequency. In addition，the design flow for the vibration suppression on shrouded blades is put forward: the first step is to increase the blade stiffness by adjusting the shroud radial position，followed by optimizing the shroud axial position to increase the resonance margin of low order modes，and finally optimizing the shroud coupling angle. The initial interference value are recommended to suppress the resonance stress amplitude.

Key words: Shroud；Fan blade；Dry friction；Vibration suppression；Mode；Response

摘要： 针对涡扇发动机带凸肩风扇叶片，考虑凸肩接触带来的刚度和阻尼的非线性影响，采用Newton-Rapson迭代与多次谐波平衡相结合的方法，研究了结构设计参数对约束模态和振动响应的影响。研究结果表明:凸肩位置是影响叶片整体刚性和共振频率的关键参数，凸肩径向相对位置设计在55% ~ 75%为宜，有利于提高叶片刚度和降低振动变形；轴向位置应靠近叶型质心，以提高凸肩的接触刚度和叶片一阶共振频率；啮合角和初始过盈量主要影响共振应力，而对共振频率影响很小。在此基础上，建立了带凸肩叶片的减振设计流程，首先通过优化凸肩径向位置提高叶片整体刚度，其次通过优化凸肩轴向位置提高低阶模态共振裕度，最后通过优化啮合角和初始过盈量抑制振动应力幅值。

关键词: 凸肩；风扇叶片；干摩擦；减振；模态；响应