Crack failure mode determination method and fatigue life prediction method based on crack failure mode determination method

Abstract

The invention discloses a crack failure mode determination method and a fatigue life prediction method based on the crack failure mode determination method and is applied to the field of reliability. A crack failure mode of a part is determined based on contribution made by normal strain and shear strain to fatigue damage, energy and critical plane approach are combined, fatigue life prediction models in two modes such as a stretching dominated failure mode and a shearing dominated failure mode are established, and the problem that the prediction error is too large due to the material dispersion property can be effectively solved, so that the prediction life does not far deviate from experiment life; and moreover, a critical plane stress-strain curve relation and a related material constant are introduced into the model establishing process, the influence on mean stress can be reflected, and the model is capable of predicting the fatigue life under proportional and non-proportional symmetrical or asymmetrical loads.

Description

technical field [0001] The invention belongs to the field of reliability, in particular to a fatigue life prediction technology of aviation metal materials or structural components. Background technique [0002] As the thrust device of the aircraft, the aero-engine is known as the "heart" of the aircraft, and its reliability and life prediction are of great significance to the safety of the aircraft. Among the mechanical failures in my country's aviation field in recent years, 80% are caused by the failure of rotating parts. With the development of the aviation industry, the requirements for the performance of aero-engines continue to increase, and the thrust-to-weight ratio continues to increase, which makes the temperature and speed of aero-turbine engines continue to increase, resulting in more complex thermal loads and mechanical cycles of aero-engine components, especially turbine rotor components. The failure problem of working under load is becoming more and more pro...

AI Technical Summary

Problems solved by technology

Although some multiaxial fatigue life prediction models in recent years can predict the multiaxial fatigue life under proportional and non-proportional loads, and can properly characterize the influence of mean stress, due to the dispersion of materials, in the absence of experimental conditions, its The crack failure mode is ofte

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