Fatigue Life Prediction Of Low Pressure Turbine Blade Of Aero-Engine

Turbine blade is one of the key components of the turbofan engine and a typical hot section component, connected with the turbine disc to provide power to ensure normal work of the engine. Turbine blade worksin bad conditions, bearing centrifugal load, aerodynamic load, thermal stress and vibration, etc. The main failure modes are low-cycle fatigue fracture, high-cycle fatigue fracture, high-temperature creep rupture, etc. In particular, in the high centrifugal load and temperature load at the same time, the turbine blades easily produce fatigue crack and high-temperature creep, to seriously influence its reliability and efficiency. So the research of turbine blade life is very import to ensure the normal and stable work of the engine.This paper based on the finite element analysis, calculatedthe turbine blades low-cycle life calculation and high-cycle load, the mainly done work as follows:(1) Finite element analysis of turbine blades. According to the geometrical structure and the load analysis of the turbine blades, model three-dimensional finite element of the turbine blade; do the thermo-elastic analysis of the blade body, getthe maximum stress and strain and the blade body dangerous place in the bottom of the blade body.Do the Elastic-plastic contact analysis of the blade tenon, getthe maximum stress and strain and the dangerous place is the third tenon tooth.(2) Turbine blade fatigue/creep life calculation. According to the result of finite element calculation and 900 h load spectrum,calculate the low-cycle fatigue life of the dangerous positions by the local stress-strain approach; calculate the creep rupture life of the dangerous positions and the highest temperature point by parameter method; calculate the creep/fatigue life ofblades by the linear fatigue damage accumulation theory, and transform to flight time.(3) High-cycle load analysis. High cycle fatigue of turbine blade is mainly caused by vibration.Use the Workbench on blade vibration analysis, get the top ten order resonance frequency of three kinds of working condition; Map the Campbell chart, calculate the critical speed of the turbine blade, and known that it will not resonate in of three kinds of working condition; based on the S-N curve and Goodman stress correction curve, calculate the high-cycle fatigue damage, cycle index, the maximum high-cycle load and the amplitude.In this paper, the result process about the load analysis, finite element analysis life calculation of turbine blades will be a reference for the life prediction ofcomplete engine and improvementof reliability.