Method for judging fatigue dangerous part of lug hole edge

A technology of dangerous parts and discrimination methods, applied in geometric CAD, design optimization/simulation, etc., can solve problems such as no longer applicable, and achieve the effect of simple and reliable judgment methods and easy promotion and calculation

Pending Publication Date: 2021-06-29
XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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AI-Extracted Technical Summary

Problems solved by technology

[0003] At present, the damage tolerance analysis of lugs often focuses on the analysis of straight lugs and symmetrical oblique lugs under straight loads. It has certain applicability to use the maximum Mises stress as the cracking criterion to determine the most likely cracking position, but When the straight lugs are subjected to oblique loads, and the oblique lu...
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Method used

In table one, according to the discriminating method of the fatigue risk position of the tab hole limit of the present application, the first fatigue risk position of the tab hole limit obtained under different angle loads by di...
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Abstract

A method for judging a fatigue dangerous part of a lug hole edge comprises the following steps: knowing structural parameters of a lug, and establishing a finite element model and a local cylindrical coordinate system for the lug structure; converting the stress value of the lug structure in the global coordinate system into a tangential stress value under a cylindrical coordinate system, and obtaining the tangential stress of each grid unit on the edge of a lug hole through finite element analysis; and according to the tangential stress value, selecting the position where the lug hole is most likely to crack, wherein the position is the fatigue dangerous part of the edge of the lug hole under the load condition.

Application Domain

Geometric CADDesign optimisation/simulation

Technology Topic

Global coordinate systemElement analysis +7

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  • Method for judging fatigue dangerous part of lug hole edge
  • Method for judging fatigue dangerous part of lug hole edge
  • Method for judging fatigue dangerous part of lug hole edge

Examples

  • Experimental program(1)

Example Embodiment

[0018] Referring to the drawings, the discriminant method of the tired risk of the ear-proof of the egg hole of the present application is known that the following steps: 1) Take the above-described ear piece structure 1 in finite element analysis software The finite element model is established, and the finite element model is divided into no less than 360 grid units in the implementation of the fingertips, establishing a local center coordinate system at the center of the ear povert, 2) in finite element analysis software. The border conditions and loads are applied to the tab structure 1, resulting in the stress value of the load under the global coordinate system, and the tangential stress of each grid unit is stress on the wall of each grid unit. Tangential component; 3) Transfer the stress value in the global coordinate system in the global coordinate system into a tangential stress value of the column coordinate system, and obtains the tangential stress of each grid unit by finite element analysis. 3) Sort the tangential stress of the ear edge of the ear, the larger the equipped ear of the grid unit, the larger the possibility of cracking, according to the size of the tangential stress value, select the ear povery 2 The most cracked position, which is the fatigue risk of the ear pad on the load condition.
[0019] According to the determination method of the fatigue risk of the above-mentioned ear, the embodiment of the present application is figure 1 The egg structure is an example, and the outer diameter of the ears 2 is 1.5, 2.0, 2.5 and 3.0, respectively, 0 °, 45 °, 90 °, 135 °, 180 °, respectively, 180 °, 180 ° (along the ear). The fatigue hazardous range of the sheet-in-axis counterclockwise counts) The fatigue risk of the load is shown in the table.
[0020] Table 1, according to the discrimination method of the fatigue risk of the ear-hole edge of the present application, the first fatigue risk of the ear-hole hole of the ear pad and the second outer diameter and the inner diameter ratio ear. Fatigue dangerous parts, the result is more accurate and credible with the existing maximum MISES stress, and the method is simple.
[0021] In a further embodiment, the outer diameter ratio RO / Ri = 2.5 is taken as an example, the maximum Mises stress and maximum stress of the ear structure parameters are 0 °, 45 °, 90 °, 135 °. And the distribution of the 180 ° load is respectively Figure 4 ~ 8.
[0022] Figure 4 Reflecting the outer diameter of the earda than RO / RI = 2.5 in the 0 ° load direction, the maximum Mises stress and the Tangential Stress are distributed;
[0023] Figure 5 Reflecting the inner diameter of the ear, the maximum Mises stress and the maximum STRESS in the 45 ° load direction is distributed in the 45 ° load direction;
[0024] Figure 6 Reflecting the outer diameter of the earda ratio RO / RI = 2.5 in the 90 ° load direction, the maximum Mises stress and the Tangential Stress are distributed;
[0025] Figure 7 Reflecting the outer diameter of the ear, the maximum Mises stress and maximum stress in the 135 ° load direction is distributed;
[0026] Figure 8 Reflecting the inner diameter of the ear, the maximum Mises stress and the maximum stress in the 180 ° load direction in the 180 ° load direction are distributed.
[0027] Table 1: Judgment comparison result
[0028]

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