考虑表面加工缺陷的轮盘疲劳寿命分析方法

An Analysis Method of Disk Fatigue Life Considering Surface Manufacturing-Induced Anomaly

为了将表面加工状态引入零构件概率寿命分析中,提出并建立了考虑表面加工缺陷的轮盘疲劳寿命分析方法。将孔的表面加工缺陷简化为表面裂纹和/或角裂纹,导出裂纹深度密度函数;借助裂纹应力强度因子经验公式及有限元分析,提出轮盘孔边裂纹应力强度因子计算的推广经验公式方法。建立了3种考虑表面缺陷尺度分布时轮盘概率寿命计算方法。以钛合金盘为例,在获得的表面缺陷分布条件下,计算了给定寿命的轮盘疲劳寿命失效概率及故障率。仿真结果表明:采用该方法可以将表面加工缺陷对疲劳寿命的影响引入构件寿命评估体系。

In order to analyze the aeroengine components＇ life at the surface manufacture state, a method for disk fatigue life analysis considering surface manufacturing-induced anomaly was presented and built. The surface manufacturing anomaly was simplified as surface cracks and/or comer cracks, and the crack density function was exported. Using the empirical formula of Stress Intensity Factor （SIF） and FEM analysis, a popularized empirical formula method to compute the SIF of a crack at hole edge of a disk was proposed and verified by FEM solution. Three methods to calculate the probabilistic life of disk considering the depth distribution of surface anomaly were built. Taking a titanium disk as an example, the failure risk and failure rate at a given life was computed, under the conditions of the gained distribution of surface anomaly. The simulation results show that the surface manufacturing-induced anomaly affeots fatigue life can be introduced in components＂ life assessment life by this method.