Method for determining allowable defect of honeycomb sandwich layer of helicopter

Abstract

The invention discloses a method for determining allowable defects of a honeycomb sandwich layer of a helicopter, belongs to the technical field of structural fatigue design of helicopters and particularly relates to a method for determining honeycomb sandwich layer structure defects of a helicopter body with defects. By prearranging internal and external defects on a honeycomb sandwich layer test piece and determining the rationality of defect parameters by adopting static strength, fatigue and remaining strength comparative tests under real load-bearing environments, bases are provided for the design and handling of such manufacturing deviations, the manufacturing and using costs of the honeycomb sandwich layer structure can be decreased and the risk in use of the defective structure is reduced.

Description

technical field [0001] The invention belongs to the technical field of fatigue design of helicopter structures, and mainly relates to a defect determination method of a honeycomb sandwich structure of a helicopter body with defects. Background technique [0002] The helicopter honeycomb sandwich structure is composed of a lightweight core and two relatively strong panels. Under the support and separation of the lightweight core, the weight of the structure hardly changes much, while the moment of inertia is greatly increased, which improves the structural bending resistance and Ability to resist buckling. As a special composite material structure, it is widely used in the structural design of aircraft, such as the tail section of a certain type of helicopter, due to its high specific strength, specific stiffness, and many advantages such as easy design of performance and large-scale integral molding. The structure and vertical tail skin make extensive use of honeycomb sandw...

AI Technical Summary

Problems solved by technology

[0003] Because the area of ​​the honeycomb sandwich structure is large at one time, and the aluminum alloy panel is thin, the contact area with the honeycomb is also small (the thickness of the honeycomb material is about 0.1mm), so it is difficult to ensure that there is no gap between the honeycomb and the aluminum alloy panel in terms of process or material. There is a situation of partial detachment / leakage; and in the process of production, processing, assembly, use, and maintenance, the surface of the aluminum alloy panel may also be damaged by collisions or impacts such as various tools, sand, stones, etc., which can be said to be detachment / Leakage and bumping are two types of defects that must be faced in the application process of honeycomb sandwich structures, and these two types of defects occur frequently and are difficult to repair, making it difficult to determine

[0004] At present, there is no reliable identification method for such defects in China, and the processing technology is immature, which often brings great confusion to production and design: scrapping or maintenance will increase production and use costs; The potential impact on safe flight is difficult to accurately grasp

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