Multi-axis fatigue life prediction method based on critical strain damage parameter

Abstract

The invention discloses a multi-axis fatigue life prediction method based on a critical strain damage parameter, and is applied to the field of multi-axis fatigue life prediction. On the basis of shearing strain damage and normal strain damage on a maximum damage parameter plane near a maximum shearing strain plane, different shearing strain correction factors and normal strain correction factors are adopted to obtain a life prediction model; and planes near the shearing strain plane are taken as candidate critical planes, and a plane where maximum damage is positioned is selected as the critical plane. By use of the method, a crack occurrence direction can be favorably matched; and in addition, a multi-axis fatigue life prediction model disclosed by the invention does not need additional material constants, fatigue test data does not need to be fit, and a corresponding program is directly adopted to calculate the fatigue life so as to be simple and quick. Meanwhile, the life prediction model which is put forward by the invention can represent an average strain influence, can adapt to various complex path loads, also can reflect non-proportional loading additional hardening, exhibits high adaptation for different materials and is high in life prediction accuracy.

Description

technical field [0001] The invention belongs to the field of multiaxial fatigue life prediction, in particular to the life prediction of aviation materials GH4169 and TC4 under the proposed multiaxial fatigue life prediction method. Background technique [0002] In engineering structures and mechanical components, fatigue-risk parts are often subjected to multi-axial fatigue loads, most of which are key components, and their life prediction is of great significance to the reliability and structural integrity of equipment systems. Especially in the field of aero-engines, the rotor components are often subjected to high temperature, high pressure and complex alternating loads, and the failure problem is becoming more and more prominent. The traditional uniaxial fatigue life prediction method can no longer meet the actual needs of current applications, and the multiaxial fatigue method occupy an increasingly important position. The multiaxial fatigue method can often predict t...

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Problems solved by technology

However, most of the current critical surface methods have additional material constants, the application is more complicated, and the material constants obtained by fitting the limited test data cannot be used in a wide range of loading situations. As a result, a large number of additional fatigue tests are required to obtain fatigue test data, and then based on these test data to determine additional material constants, which is expensive and inconvenient to apply

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