Thermomechanical Fatigue Life Prediction Method of the Trailing Edge Holes in the Turbine Blade for Turboshaft Engine

Abstract

In this paper, a thermomechanical fatigue (TMF) life analysis method considering stress relaxation was established for turbine blade in a turboshaft engine. The nonlinear creep deformation of a superalloy is predicted by coupling creep damage in the framework of viscoplastic theory. The results revealed that 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 is within the dispersion range of the inherent properties of material creep deformation. 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 are clarified, and a new method is provided for determining the local dangerous points on the blade. With the help of the linear damage cumulative life theory, the fatigue creep life of the trailing edge hole of a turbine blade considering the stress relaxation is obtained, which provides a more reasonable and better engineering application method for the blade life evaluation.