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A Judgment Method for the Critical Point of Dfr Two-way Modification of Spanning Connection Structure

A connection structure and critical point technology, applied in the field of judgment of DFR two-way correction critical point, to achieve efficient calculation, save manpower and material resources

Active Publication Date: 2018-05-29
XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The present invention provides a method for judging the critical point of the spanwise connection structure DFR two-way correction, which is characterized in that it can efficiently solve the problem of unnecessary correction caused by the inability to judge the critical point in the existing method, and is easy to use. Practical

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  • A Judgment Method for the Critical Point of Dfr Two-way Modification of Spanning Connection Structure
  • A Judgment Method for the Critical Point of Dfr Two-way Modification of Spanning Connection Structure

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Embodiment Construction

[0040] Given two different sets of parameters:

[0041] a)t s =6.6mm,t sp =8.0mm, d=8.0mm, p=32mm, σ g =120.5MPa,τ s =35.8MPa;

[0042] b)t s =6.3mm,t sp =7.6mm, d=8.0mm, p=32mm, σ g =118.1MPa,τ s = 6.8MPa.

[0043] According to the specific technical solution mentioned above, the above two groups of parameters are calculated respectively, so as to determine whether two-way correction is required.

[0044] 1. Determine if figure 1 DFR values ​​for spanwise structures shown:

[0045] DFR = DFR base A·B·C·D·E·R C

[0046] The DFR calculation process here is completely consistent with the existing method in the Civil Aircraft Structure Durability and Damage Tolerance Design Manual. The DFRs corresponding to only two groups of parameters are given as follows: a) DFR=115MPa; b) DFR=120MPa.

[0047] 2. Calculate

[0048] For the specific part of the calculated spanwise connection structure in the aircraft, the fatigue stress spectrum of the part is calculated, and ...

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Abstract

The invention provides a judgment method of a dual adaptation critical point of expansion direction connection structure DFR (Detail Fatigue Rating). The judgment method comprises the following steps: (1) determining an expansion direction connection structure DFR value: obtaining the DFR value according to a formula DFR=DFRbase*A*B*C*C*D*E*Rc; and (2) calculating ([Tau]s / [Delta]g)*(ts / tp): aiming at the specific position of the calculated expansion direction connection structure in an airplane, calculating to obtain the fatigue stress spectra of the position, extracting DFR reference stress [Delta]g, shearing stress [Tau]s in the spectra corresponding to the DFR reference stress [Delta]g, the basic thickness ts of a wallboard and the thickness tsp of the wallboard boss of a connection position, and calculating to obtain the numerical value of the ([Tau]s / [Delta]g)*(ts / tp).

Description

technical field [0001] The method for judging the critical point of the DFR bidirectional correction of the spanwise connection structure provided by the patent of the present invention. Background technique [0002] The spanwise connection structure is a common connection structure in aircraft structures. [0003] Due to the fact that there are three-dimensional stresses in the spanwise connection structure, after the DFR value is calculated according to the DFR calculation method of the spanwise connection structure, it is often necessary to perform bidirectional correction of the DFR according to the bidirectionally loaded joints. However, the existing methods do not define when two-way correction is required (that is, including thickness, fastener diameter, fastener spacing and other structural parameters and the critical relationship between stress size parameters and DFR correction), and it is impossible to judge whether correction is required before correction. It wi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F19/00G01M99/00
Inventor 朱亮张彦军雷晓欣李小鹏
Owner XIAN AIRCRAFT DESIGN INST OF AVIATION IND OF CHINA
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