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Method for estimating calendar life of aircraft structure

A technology for life estimation and aircraft structure, which is applied in calculation, special data processing applications, instruments, etc., to achieve the effect of convenient engineering application

Inactive Publication Date: 2011-09-14
XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of method belongs to the research content of fracture mechanics, and the engineering application still needs the support of initial fatigue quality test data

Method used

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  • Method for estimating calendar life of aircraft structure
  • Method for estimating calendar life of aircraft structure
  • Method for estimating calendar life of aircraft structure

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0036] Estimation of Fatigue Life of LY12CZ Center Hole Specimen

[0037] a) Under the influence of calendar time, prepare the fatigue load spectrum

[0038] The load spectrum is a random spectrum type, one loading cycle contains 2110 peaks and valleys, and the total damage of each block spectrum to the structure is 0.05. The load spectrum is completed in one calendar year. In order to simplify the calculation, it is assumed that 2110 load peaks and valleys are evenly distributed in one year (this distribution method is intended to illustrate the calculation process, in fact, it should be based on the aircraft service / training plan. The second ups and downs are spread out over the course of a year).

[0039] The fatigue load spectrum considering calendar time can be expressed as:

[0040] f(S, n, y j )=f(S, 2110, y j )(j=1,...,k)

[0041] b) Establish the relationship between calendar time and fatigue life

[0042] According to the atmospheric aging test results of LY12C...

example 2

[0053] Fatigue life estimation of an aircraft wing body joint

[0054]The joint lug material is LC4CS forging, and the fatigue test load spectrum of the joint is an eight-level program block spectrum (Table 1). The fatigue test life of the joint simulation piece (when there is a 0.5mm crack on the side of the lug hole) is 50-80 pieces.

[0055] Table 1: Block Spectrum of Wing Body Joint (200 Flight Hours)

[0056] load level

1

2

3

4

5

6

7

8

[0057] S max (MPa)

92.1

196.0

33.4

423.7

383.5

274.6

191.2

161.8

S min (MPa)

41.2

49.0

41.2

41.2

41.2

41.2

47.8

41.2

number of cycles

145

146

59

1

13

234

137

40

[0058] Firstly, the median life of joints is calculated by deterministic fatigue life method to be 59 pieces, which is consistent with the test life results. In order t...

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Abstract

The invention discloses a method for estimating calendar life of an aircraft structure, belonging to the technical field of aircraft life estimation and particularly relating to improvement on the method for estimating the calendar life of the aircraft structure. The method mainly comprises three steps of: 1, compiling a fatigue load spectrum under the condition of considering influence of calendar time; 2, establishing relation between the calendar time and fatigue life; and 3, estimating the calendar life of the structure by using a linear accumulated damage theory. The method has the advantages that: influences of the calendar time and an environmental factor are simultaneously considered during estimation of fatigue life; a load-environment process which is actually suffered by the aircraft structure can be really reflected; a few parameters are required to be determined; and engineering application is facilitated.

Description

technical field [0001] The invention belongs to the technical field of aircraft life estimation, and in particular relates to the improvement of an aircraft structure calendar life estimation method. Background technique [0002] At present, there are mainly the following methods for evaluating the calendar life of aircraft structure: [0003] (1) An empirical method for determining the calendar life of an organism [0004] At present, the total calendar life and overhaul cycle are determined mainly based on the statistical data of natural elimination of aircraft, the practice of leading flight of some aircraft, and the experience of overhaul at home and abroad. related to experience. [0005] (2) Linear accumulation model of corrosion damage [0006] By establishing the T-H curve of the relationship between the temperature of the corrosive medium and the critical corrosion time, taking the critical corrosion amount Dc of the structure / material at different temperatures a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F19/00
Inventor 王斌团王继普王新波
Owner XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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