A Method for Determining the Area of ​​Crack Relief Ribs in Integral Wing Spars of Aircraft

An integral and spar technology, which is applied in the field of determining the area of ​​the crack arresting rib of the integral spar of the aircraft, can solve the problem of failing to provide the determination method and research of the area of ​​the integral spar crack arresting rib, and achieve the calculation of the profile characteristics. The effect of convenience, correct theoretical basis and clear analysis steps

Active Publication Date: 2016-03-09
XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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Problems solved by technology

[0003] Regarding the research on the structural parameters of the crack arresting ribs, no foreign public information has been found. Domestic experiments have been carried out on the overall spar. The influence of the damage tolerance performance of the spar has been studied. Although it is pointed out that the area of ​​the crack arrest rib is the most sensitive structural parameter affecting the damage tolerance performance of the whole spar, the most sensitive structural parameter (the area of ​​the crack arrest rib) has not been studied. Determining the method for research, failed to provide a method for determining the area of ​​the overall spar crack arrest rib

Method used

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  • A Method for Determining the Area of ​​Crack Relief Ribs in Integral Wing Spars of Aircraft
  • A Method for Determining the Area of ​​Crack Relief Ribs in Integral Wing Spars of Aircraft
  • A Method for Determining the Area of ​​Crack Relief Ribs in Integral Wing Spars of Aircraft

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[0030] The present invention will be further described in detail with a specific example below.

[0031] A method for determining the area of ​​an aircraft integral spar crack arresting rib, comprising the following steps:

[0032] Known: H=300mm, W 1 =W 2 =50mm,t 1 = t 2 = 4.5mm, a 1 = 15mm, b 1 =4mm, t=3mmσ b =511 MPa. , K C = 2277 MPa mm .

[0033] Step 1. Determine the bending moment M of the integral spar:

[0034] M=σ 1 *s*H=180*50*4.5*300=1.215×10 7 Nmm;

[0035] Step 2. Assign an initial value A to the area of ​​the arresting rib 1 =15*4, calculate the distance y=114.8mm from the neutral axis of the structural part of the non-shaded area of ​​the overall spar to the crack arresting rib, and the flexural modulus I=4158122mm 4 ;

[0036] Step 3. Axial stress of crack arresting ribs

[0037] σ 2 = ...

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Abstract

The invention belongs to the field of aviation fatigue damage tolerance and particularly relates to a method for determining the area of a crack arrest rib of an aircraft integral wing spar. The method comprises the steps of: determining a bending moment M of the integral wing spar; determining a distance y from a neutral axis of an uncracked part in the integral wing spar to the crack arrest rib and an anti-bending modulus I; and calculating a crack tip stress intensity factor K when a lower edge strip of the wing spar is cracked and is expanded to the crack arrest rib and carrying out judgment. The invention discloses a method for determining structural parameters of the crack arrest rib of the integral wing spar from the field of research on the fatigue damage tolerance according to the structural form and the force transfer characteristic of the integral wing spar. The principle basis used by the method is correct; the analysis steps are clear and simple; and the calculation on section characteristics is convenient for automation iterative computation of a computer. The disclosure of the method solves the difficult problem of determining the area of the crack arrest rib of the integral wing spar.

Description

technical field [0001] The invention belongs to the field of aviation fatigue damage tolerance, and in particular relates to a method for determining the area of ​​crack arresting ribs of an aircraft integral spar. Background technique [0002] With the wide application of the overall structure in the design of aircraft structures, the wing spar structure also began to change from the combined spar (see figure 1 ) to the integral spar (see figure 2 ) design shift. This overall structure has good anti-fatigue performance because it reduces the use of fasteners, stress concentration areas and potential fatigue sources. However, due to the reduction of "natural" crack arrest elements such as rivet holes, its damage tolerance performance may be adversely affected. Since the lower edge of the integral wing spar is subjected to tensile stress, once a crack appears at the edge of the hole, it may spread to the beam web. If the crack expands too fast on the web, it may affect th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B21/28G01M5/00
Inventor 翟新康秦剑波张彦军
Owner XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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