A method for predicting that detail life of a structure under high-low cycle fatigue load

Abstract

The invention discloses A method for predicting that detail life of a structure under high-low cycle fatigue load which includes such steps as determining the low cycle fatigue stress level of the structure material, obtain the S-N curve, and one of the low cycle fatigue stress levels is selected as the low cycle fatigue stress level sigma L; determining Then the high and low cycle fatigue test conditions, and the S-N curve, acquiring the relationship curve between high cycle fatigue life and amplitude. Then, setting up the fatigue life prediction model of the modified parameters to be determined, and obtaining the modified parameters in the model are determined and the fatigue life prediction model. Finally, determining the fatigue life under the load conditions that need to be evaluated.The present application is independent of the specific form of the structure and the loading condition, and can be used for fatigue life prediction of key structural details in aircraft structures, shortening model development cycles, and reducing development costs.

Description

technical field [0001] The application belongs to the technical field of material fatigue life prediction, and in particular relates to a method for predicting the life of structural details under the action of high-low cycle composite fatigue loads. Background technique [0002] Fatigue is one of the most important causes of aircraft structure failure and damage, and it widely exists in machinery, vehicles, welded structures, aircraft engines and other structures. The loss of personnel and economic loss caused by the failure of engineering structures caused by fatigue problems is huge. Therefore, the study of fatigue problems can not only improve the reliability and economy of engineering structures, but also ensure the safety of personnel. In traditional research, the high-low-cycle composite load fatigue problem of the structure is generally simply decomposed into high-cycle fatigue problem or low-cycle fatigue problem for research, which will get an unreliable fatigue li...

AI Technical Summary

Problems solved by technology

In traditional research, the high-low-cycle composite load fatigue problem of the structure is generally simply decomposed into high-cycle fatigue problem or low-cycle fatigue problem for research, which will get an unreliable fatigue life analysis result, which may cause serious property damage. loss or personal injury

During the working process of aircraft and engine, the structure is alternately subjected to these two kinds of fatigue loads, and the compound fatigue problem cannot be calculated by simple stress analysis method or strain analysis method, and it is impossible to study low-cycle fatigue or high-cycle fatigue alone. Accurately analyze the fatigue failure of the actual structure, so it is necessary to study the life analysis method of structural details under high and low cycle composite fatigue loads

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