A method for determining impact energy cutoff value of aircraft composite structures based on probability and statistics theory

A probability statistics theory and composite material technology, which is applied in the field of determining the impact energy cut-off value of composite material structures of large civil transport aircraft, can solve the problems of not considering the impact damage energy level, conservative design, and the inability to truly reflect the impact of the aircraft, and achieve reduction The effect of conservative design

Pending Publication Date: 2018-12-18
AVIC SAC COMML AIRCRAFT
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Problems solved by technology

For the limit load, Boeing adopts that in the whole life of the aircraft, the impact event energy suffered by no more than 10% of the aircraft will be equal to or higher than the upper limit of impact damage, and the limit load analysis does not consider the upper limit of the impact damage energy level. approach introduces an unnecessarily conservative design
[0004] Due to the late start of the application of composite materials in commercial aircraft, no standard method for determining the cut-off value of impact energy has been developed. bring too conservative design

Method used

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  • A method for determining impact energy cutoff value of aircraft composite structures based on probability and statistics theory
  • A method for determining impact energy cutoff value of aircraft composite structures based on probability and statistics theory
  • A method for determining impact energy cutoff value of aircraft composite structures based on probability and statistics theory

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Embodiment 1

[0048] The specific implementation process of the present invention will be described in detail below in conjunction with the accompanying drawings. The specific steps describe the process by taking 1644 injuries from F-4, F-111, A-10, and F-18 as examples. The entire energy cut-off value determination method is integrated in the flowchart (see attached figure 2 ). The basic implementation process is as follows:

[0049] Step 1 defines the probability P of the occurrence of two energy cut-off values a And the formula for calculating the energy cut-off value.

[0050] Validation of aircraft composite structures requires the determination of realistic impact energy cutoffs for load requirements. There are some real impact threat levels that need to be considered when determining the energy cutoff. To establish a determination method based on semi-probability or probability, two energy cut-off values ​​must first be defined. The first one is the maximum impact energy that c...

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Abstract

A method for determining impact energy cutoff value of aircraft composite structures based on probability and statistics theory. This method fills in the blank of determining the cutoff value of composite material structure of commercial aircraft and the history of copying Airbus Boeing experience directly. In order to ensure the integrity of the structure in the whole service life, on the premiseof ensuring its safety and reliability, the method uses the probability statistics theory, the actual damage data of aircraft composite structure during assembly, operation and maintenance are studied comprehensively, and finally a scientific, complete and systematic determination method of energy cutoff value is formed.

Description

technical field [0001] The invention relates to a method for determining the impact energy cut-off value of a composite material structure of a large civil transport aircraft, which belongs to a design method of static strength of a composite material body structure, a damage tolerance design method and a conformity certification method. Background technique [0002] The most dangerous damage that composite primary structures can experience throughout the aircraft's service life is damage from accidental foreign object impact events. When severe impact damage occurs to the main composite structure, until the damage is discovered, the rest of the structure should be able to withstand reasonable loads without damage or excessive structural deformation. Based on the above characteristics and requirements of composite material structure design, for the design of civil aircraft composite material structure, the advisory circular AC20-107B puts forward clear and detailed strength ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/23
Inventor 郑双贾大炜支晗刘旭何续斌黄文超
Owner AVIC SAC COMML AIRCRAFT
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