轴流叶片单边贯穿型裂纹应力强度因子的计算方法

Computational Method of Stress Intensity Factor for Axial Flow Blade with Single-side Penetrating Crack

叶片是轴流式压缩机等透平机械的主要转动部件,在交变荷载作用下易发生疲劳断裂破坏。合理分析叶片裂纹的应力强度因子,对评估其断裂力学特性具有实际意义和应用价值。本文基于平板应力强度因子理论解,采用扩展有限元法计算含单边贯穿型裂纹的轴流叶片的I型应力强度因子,对轴流叶片的裂纹形状因子进行了修正。考虑了裂纹位置和板厚对轴流叶片应力强度因子的影响,采用多项式拟合,提出叶片应力强度因子的半解析解公式。通过与实际轴流叶片仿真分析结果对比,进一步修正半解析解公式,提出用于快速评估含单边裂纹的压缩机叶片断裂力学特性的半解析解。本文提出的计算方法有效提升了实际轴流叶片应力强度因子的分析精度和效率。

Blade is the main rotating part of turbo machinery such as axial flow compressor,which is prone to fatigue fracture under alternating load.Reasonable analysis of stress intensity factor of blade crack has practical significance and application value to evaluate its fracture performance properties.In this paper,based on the theoretical solution of the plate stress intensity factor,the extended finite element method is used to calculate the Mode-Ⅰstress intensity factor of an axial flow blade with a unilateral crack,and the crack shape factor of axial flow blade is modified.The semi-analytical solution of the blade stress intensity factor was proposed by polynomial fitting considering the location of crack and the plate thickness on stress intensity factor of an axial blade.Furthermore,comparing with the simulation results of axial flow blades,the modified semi-analytical solution for rapid evaluation of fracture mechanical performance of compressor blades with unilateral cracks is presented.The calculation method proposed in this paper can effectively improve the analytical accuracy and efficiency of the actual axial flow blade stress intensity factor.