某涡轴发动机涡轮叶片尾缘孔的蠕变-疲劳寿命预测方法

Creep-fatigue life prediction method of tail edge holes in turbine blade for a turboshaft engine

针对某涡轴发动机的涡轮叶片,建立了考虑应力松弛的蠕变-疲劳寿命分析方法。通过在黏塑性理论框架内耦合蠕变损伤,对某高温合金的非线性蠕变变形进行了数值模拟。结果表明:基于对某涡轮叶片的弹塑性-蠕变分析研究,明确了叶片上前缘和尾缘等关键部位的蠕变损伤及其演化规律,也为确定叶片上的局部危险点提供了一种方法。该模型针对弹塑性应力应变曲线计算误差小于5%,而针对蠕变曲线的模拟精度则处于材料蠕变变形固有属性分散范围内。借助于线性损伤累积寿命理论,分析得到了某涡轮叶片尾缘孔局部考虑了应力松弛的蠕变-疲劳寿命,从而为叶片寿命评价提供了更为合理、工程化应用更好的方法。

A creep-fatigue life analysis method considering stress relaxation was established for turbine blade in a turboshaft engine. The nonlinear creep deformation of a superalloy was pre-dicted by coupling creep damage in the framework of viscoplastic theory. The results revealed that based on the elastic-plastic creep analysis of a turbine blade,the creep damage and its evolution law of the leading edge and trailing edge of the blade were clarified,and a method was provided for determining the local dangerous points on the blade. The calculation error of the model for the elastic-plastic stress-strain curve was less than 5%, while the simulation accuracy for the creep curve was within the dispersion range of the inherent properties of material creep deformation.With the help of the linear damage cumulative life theory, the creep - fatigue life of the trailing edge hole of a turbine blade considering the stress relaxation was obtained,providing a more rea-sonable and better engineering application method for the blade life evaluation.