某型发动机风扇二级叶片/盘疲劳寿命研究

Fatigue life research of 2nd fan blade and disk for aero engine

摘要:

对某发动机风扇二级叶片/盘疲劳寿命进行了理论计算和试验研究。应用Ansys软件建立了该发动机风扇二级叶片振动分析有限元计算模型,并对其一阶弯曲共振时的应力分布进行有限元数值仿真分析,得到了叶尖振幅与叶背应力的关系；基于一阶弯曲共振模态,对叶片进行了疲劳寿命试验,获得了改型前后叶片的疲劳寿命。建立了轮盘应力分析有限元模型,计算得到了轮盘的应力分布,并以此应力分布为基础,计算得到了轮盘的疲劳寿命。研究结果表明:改型前后,叶片的疲劳寿命增大了4.1倍；叶片改型前后,无论是大间隙还是小间隙,改型后盘的疲劳寿命较改型前有所下降,但改型前后盘的疲劳寿命均满足设计要求。

Abstract:

The fatigue life of some turbofan engine’s 2nd fan blade and disk is researched by computation and experimentation. The finite element compute model of the blade for vibration analysis is built by Ansys software, and its stress distribution on the first order bending resonance state is computed and analyzed by finite element method, the relationship between the vibration amplitude of blade tip and the stress of blade back is obtained. Based on these, the fatigue life of the blade is tested and researched, and so the fatigue life of the blade which is before and after the remodel. The finite element model for stress analysis of the disk is built, the stress distribution of the disk is computed, and based on this, the fatigue life of the disk is computed at the two high-point of the clearance between the disk hole and the pin. The research result shows that after the remodel the fatigue life of the blade increases by 4.1times, Whether the clearance is big or small, the fatigue life of the disk decreases slightly, but whether before or after the remodel, the fatigue life of the disk meets the design specification well.