Method for determining fatigue crack safe damage growth period of airplane structure

A technology for fatigue crack growth and fatigue cracks, which is applied in the field of determining the safe damage growth period of fatigue cracks in aircraft structures

Active Publication Date: 2014-08-06
AIR FORCE UNIV PLA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, there is no method for determining the safety damage propagation cycle of aircraft structures that considers inspection and repair information at home and abroad. In order to fully tap the service life potential of aircraft wit

Method used

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  • Method for determining fatigue crack safe damage growth period of airplane structure
  • Method for determining fatigue crack safe damage growth period of airplane structure
  • Method for determining fatigue crack safe damage growth period of airplane structure

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Embodiment

[0088] A method for determining the safe damage propagation period of aircraft structure fatigue cracks based on inspection and repair times, the specific steps are as follows:

[0089] Step 1): median period of crack growth [N 50 ] of OK.

[0090] Determine the median period of crack growth based on the results of the structural crack growth test [N 50 ]. Assume that the structural crack growth test results of n test pieces are: N 1 ,...,N n .

[0091] When the crack growth life follows a lognormal distribution: it is known to those skilled in the art that the crack growth median period [N 50 ]for:

[0092] [ N 50 ] = 10 Σ i = 1 n 1 g N i ...

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Abstract

The invention discloses a method for determining the fatigue crack safe damage growth period of an airplane structure. The method for determining the fatigue crack safe damage growth period of the airplane structure is characterized by comprising the steps of (1) determining a crack growth mid-value period, (2) determining the fatigue crack growth dispersion coefficient, (3) determining the structure safe damage growth period based on the frequency of overhauling. According to the method for determining the fatigue crack safe damage growth period of the airplane structure, a theoretical method is provided for prolonging the service life of the airplane structure and guaranteeing safe flight of an airplane. Compared with an existing method for determining the fatigue crack safe damage growth period of the airplane structure, the method used for determining the fatigue crack safe damage growth period of the airplane structure and based on the frequency of overhauling has the advantages that information of structure overhauling is considered when the safe damage growth period is determined.

Description

technical field [0001] The invention belongs to the technical research field of aircraft structure damage tolerance, and in particular relates to a method for determining the safe damage propagation cycle of aircraft structure fatigue cracks based on inspection and repair times. Background technique [0002] In my country's military standard "Aircraft Structural Integrity Program" (GJB775.1-89) and "Aircraft Damage Tolerance Requirements" (GJB776-89), starting from ensuring the minimum safety of the aircraft structure, new aircraft designs and old aircraft The continuous airworthiness of the aircraft proposed damage tolerance requirements. [0003] Damage tolerance is a property of structures. This property allows a structure to retain its required residual strength during a service life without repairs after having undergone specified levels of fatigue, corrosion, accidental and discrete damage. The purpose of damage tolerance requirements is to ensure that structural crac...

Claims

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Application Information

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IPC IPC(8): G06F19/00B64F5/00B64F5/40B64F5/60
Inventor 何宇廷张海威崔荣洪杜金强安涛
Owner AIR FORCE UNIV PLA
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