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

Abstract

The invention discloses a method for determining a theoretical value dispersion coefficient of the crack forming life of an aircraft structure. The method comprises the following steps: establishing a crack propagation direction coordinate identification line; determining the position of a fracture analysis measurement point; calculating the crack propagation rate of the fracture analysis measurement point position; calculating a crack propagation life test value; calculating a crack formation life test value; calculating a crack formation life theoretical value; and calculating a crack formation life dispersion coefficient, namely the crack formation life dispersion coefficient of the aircraft structure. According to the technical scheme, the adopted theoretical analysis method is correct, the engineering concept is clear, and the steps are clear; the method can be used for determining the aircraft structure crack formation life dispersion coefficient, and can also be used for determining a test piece crack propagation life test value through fracture analysis; and the problem that a fatigue life theoretical value is greatly different from a test value due to factors such as unstable performance of a material adopted by a structural member and unstable production and manufacturing process in an existing calculation mode of the crack formation life dispersion coefficient 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 formation 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 formation life have a large dispersion. [0003] In the design of aircraft structure, it is very important to calculate the fatigue life of structural parts. Fatigue life analysis methods are relatively mature, and methods such as nominal stress legislation and stress severity coefficient method are generally used to calculate crack formation life. [0004] However, when calculating the formation life, although the fatigue life dispersion coefficient has been considered accordi...

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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 formation life of an aircraft structure, to solve the existing calculation method of the dispersion coefficient of the crack formation life. Due to factors such as instability in the production and manufacturing process of parts, there is a big difference between the theoretical calculation value of fatigue life and the fatigue life test value

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