Undercarriage fatigue life analysis method based on finite element method

Abstract

The invention provides an undercarriage fatigue life analysis method based on a finite element method, which comprises the steps of establishing a finite element model of an undercarriage structure; extracting unit loads in the XYZ direction and the -X-Y-Z direction of a whole-aircraft coordinate system and unit loads applied to an undercarriage structure in the applying direction of an undercarriage retracting and releasing actuator cylinder from the axle center and the tire departure point of the finite element model, thereby obtaining 13 finite element unit stress calculation models of the axle center in the XYZ and -X-Y-Z six directions, the tire departure point in the XYZ and -X-Y-Z six directions and the retracting and releasing actuator cylinder in the application direction; applying each load point in the load spectrum to the 13 finite element unit stress calculation models to obtain the stress of each load point so as to obtain a stress spectrum comprising a plurality of load points. According to the method, the stress spectrum of each section is obtained, the undercarriage damage of each load point is calculated, the undercarriage damage of each load point is accumulated to obtain the total damage under the whole load spectrum, and then the fatigue life of the undercarriage is obtained.

Description

technical field [0001] The application belongs to the technical field of aircraft structure design, and in particular relates to a landing gear fatigue life analysis method based on the finite element method. Background technique [0002] The landing gear is an important load-bearing structure of the aircraft. The early aircraft landing gear was designed according to the static strength. It was believed that as long as the static strength requirements were met and the static test requirements were met, the structural safety could be guaranteed. With the continuous enrichment of practical experience, people realize that only the static strength design is not enough, the damage of the landing gear is caused by fatigue, and the fatigue damage occurs under the action of the alternating load with the load lower than the design load, the total damage It starts locally. It is even more important to detect and determine the weak points of fatigue early. [0003] There are three ma...

AI Technical Summary

Problems solved by technology

For simple components, it can be calculated using conventional methods; for complex structures, the stress concentration parts are often accompanied by many load spectrum conditions of the landing gear, which brings a lot of trouble to the life estimation work, and the stress concentration parts need Find the manual to get the empirical value, compare the structural size without taking different values, and there are many uncertainties, and the accuracy needs to be verified

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