Method for determining dispersion coefficient of theoretical value of aircraft structure crack propagation life

Abstract

The invention discloses a method for determining a dispersion coefficient of a theoretical value of aircraft structure crack propagation life, and the method comprises the following steps: sequentially measuring a plurality of coordinate points on a crack propagation track of a test piece, and recording cycle times corresponding to the measured coordinate points on the crack propagation track of the test piece; in the static strength finite element model, selecting an analysis area according to the area where the crack is located, and performing mesh refinement on the analysis area; establishing a finite element model of the crack-containing structure, and sequentially calculating stress intensity factors of crack tips of the test piece; calculating a theoretical value of crack propagation life according to the stress intensity factor of each crack tip; calculating a crack propagation life test value according to the cycle index; and calculating the dispersion coefficient of the theoretical value of the crack propagation life according to the theoretical value and the test value of the crack propagation life. According to the technical scheme, the problem that the theoretical value of the crack propagation life and the test value of the crack propagation life are generally greatly different in the existing calculation mode of the crack propagation life is solved.

Description

technical field [0001] The invention relates to but not limited to the technical field of aviation fatigue fracture, in particular to a method for determining the dispersion coefficient of the theoretical value of crack propagation life of an aircraft structure. Background technique [0002] In the field of aviation fatigue fracture, due to factors such as unstable materials, unstable manufacturing processes, and differences in calculation methods, the theoretical calculation and test values ​​of crack growth life are highly dispersed. [0003] In the design of aircraft structure, it is usually necessary to carry out fatigue and damage tolerance analysis and evaluation on key structural parts and important parts. When the fracture mechanics method is used for damage tolerance analysis, the cracking mode of the structural part is generally assumed first, and then the crack growth life of the structural part is calculated. [0004] However, at present, when calculating the cr...

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Problems solved by technology

[0005] The purpose of the present invention is: the embodiment of the present invention provides a method for determining the dispersion coefficient of the theoretical value of the crack growth life of an aircraft structure, so as to solve the existing calculation method of the crack growth life. Unstable manufacturing process and other factors lead to the problem that there is usually a large difference between the theoretical value of crack growth life and the test value of crack growth life

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