Multi-axis fatigue test method for full-size structural member of aircraft

Abstract

The invention discloses a multi-axis fatigue test method for a full-size structural member of an aircraft, and relates to the field of fatigue life tests for structural members of aircrafts. The method comprises the following steps: (1) obtaining a stress concentration part of the structural member by finite element simulation calculation; (2) sticking strain gauges on the part or around the stress concentration part; (3) recording actual measurement spectrums of each strain gauge and each strain rosette, and filtering to obtain a test strain spectrum; (4) analyzing the stress of the aircraftstructural member, simplifying the external force, and developing a test bed according to the simplified external force; (5) converting the actually measured strain spectrum into a multidirectional external force load spectrum of the test bed by using finite element optimization calculation; and (6) loading a rising and falling load spectrum, comparing whether the relative error between the strainvalue of the load spectrum and the actually measured strain spectrum on the aircraft is less than 10%, if so, carrying out a fatigue life test, and otherwise, returning to the step (4) to carry out stress analysis again. Test results show that the method can well reproduce the multidirectional stress condition of the aircraft structural member in actual use.

Description

technical field [0001] The application field of the present invention belongs to the technical field of fatigue test of full-scale structural parts of aircraft, and in particular relates to a multi-axis fatigue test method of full-scale structural parts of aircraft. Background technique [0002] The main failure mode of the aircraft structure is fatigue damage, so it is necessary to use the actual flight load history of the aircraft to carry out the fatigue test of the entire aircraft when the aircraft is in service, so as to evaluate the fatigue life of the entire aircraft, so that the aircraft can reach its service life in advance and discover the aircraft structure in time. Take maintenance measures in advance for weak links. However, the test period of the fatigue test of the whole aircraft is long, and the specific structure is not targeted, and it cannot truly reflect the complex multi-directional (multi-axis) loading conditions of the specific structure of the aircraf...

AI Technical Summary

Problems solved by technology

However, the test period of the fatigue test of the whole aircraft is long, and the specific structure is not targeted, and it cannot truly reflect the complex multi-directional (multi-axis) loading conditions of the specific structure of the aircraft when it is in service, resulting in inaccurate life determination. Therefore, the special fatigue test technology invented for the specific structural parts of the aircraft has very important engineering practical significance.

[0003] At present, most of the fatigue test methods for aircraft structural parts are uniaxial fatigue tests, and most of the aircraft structural parts are in the multi-axial fatigue state during actual service. At this time, the traditional uniaxial fatigue test method will not be able to truly reflect the aircraft structure. The force state of the parts in service, and it is impossible to accurately determine the life of the aircraft structural parts

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