A Method for Predicting the High-low Cycle Combined Fatigue Life of Aeroengine Turbine Blades

Abstract

The invention discloses a high-low cycle composite fatigue life prediction method of an aero-engine turbine blade, which comprises the following steps of correcting composite fatigue damage into highcycle fatigue damage, low cycle fatigue damage and coupling damage based on a linear cumulative damage model; defining high-cycle damage and coupling damage as variable damage based on service load characteristics of the aero-engine; determining variable damage as a function of high-cycle fatigue life and four characteristic parameters according to the high-cycle and low-cycle composite test loadspectrum, obtaining an expression of the variable damage, introducing an equivalent force amplitude ratio, establishing a high-cycle and low-cycle composite fatigue life prediction model, and predicting the composite fatigue life of the high-cycle and low-cycle composite fatigue life prediction model. According to the method, the fatigue life of the turbine blade under the composite loading condition can be rapidly measured by the aero-engine, and the theoretical reference is provided for reliability design and evaluation of metal materials and the turbine blade.

Description

technical field [0001] The invention relates to fatigue prediction of turbine blades of aero-engines, in particular to a component fatigue life prediction method of turbine blades of aero-engines under high-low cycle composite loads. Background technique [0002] During the operation of turbine blades of aero-engines, fatigue-related failure modes account for about half of the total failure of turbine blades. Fatigue failure seriously threatens flight safety. At present, most of the fatigue failures of aeroengine turbine blades are concentrated in the fields of pure low cycle fatigue and pure high cycle fatigue. However, in actual service, the turbine blades are simultaneously subjected to low-frequency high-amplitude centrifugal loads and high-frequency low-amplitude vibration loads superimposed on it. Among them, high-amplitude centrifugal loads lead to low-cycle fatigue failure, low-amplitude vibration loads are far smaller than the fatigue limit of turbine blades, and ...

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Problems solved by technology

[0004] In order to solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide a method for predicting the life of materials and turbine blade components under high and low cycle composite fatigue loads, which solves the problem that the current inability to accurately predict materials and turbine blades at high and low Life Estimation Problems Under Cyclic Compound Loads

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