Fatigue life prediction method of mechanical component under variable amplitude loading

Abstract

The invention relates to a fatigue life prediction method of a mechanical component under variable amplitude loading and aims to disclose that the secondary load and overload strengthening can not be prevented in terms of material and structure failure mechanism under the variable amplitude loading and the material and structure fatigue life prediction under complex serving condition and the like. The method includes that on the basis of an S-N curve of the mechanical component, a damage line is introduced, service life in each process is predicted, finally the obtained fatigue life of the mechanical component under the variable amplitude loading is an accumulated sum of a strengthening process service life, a damage-free process service life and a damage process service life of the load, during the service life prediction process, the secondary load strengthening effect and overload damage-free effect under the variable amplitude loading are fully considered, and the load acceleration damage process is further considered. The prediction process is close to the test and actual conditions, and the method is remarkably superior to prior methods. The method is applicable to the service life prediction of steel mechanical component under high-cycle fatigue damage.

Description

technical field [0001] The invention relates to a fatigue prediction method, in particular to a fatigue life prediction method of mechanical components based on damage lines and stress life lines under variable amplitude loads. Background technique [0002] Most of the mechanical parts in engineering are subjected to variable amplitude loads. Generally, variable amplitude loads include both overloads above the fatigue limit and secondary loads below the fatigue limit. Research on fatigue life prediction under variable amplitude loading has always been an important subject in fatigue research. [0003] Fatigue life prediction methods such as Miner’s law, modified Miner’s law, bilinear theory, and Corton-Dolan theory are commonly used in engineering, and the damage effect of the load is considered too much, and the strengthening of the load is ignored. Therefore, when predicting the weakly strengthened load spectrum Or under the original load spectrum, there is a large differ...

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Problems solved by technology

[0005] The present invention is aimed at the problem that there is a large difference between the prediction results of the current fatigue prediction method for mechanical components and the test results, and proposes a fatigue life prediction method for mechanical components under variable amplitude loads. Based on the curve, introduce the damage line

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