Aircraft structure damage diagnosis method based on stable boundary and POD method

Abstract

The invention discloses an aircraft structure damage diagnosis method based on a stable boundary and a POD method. On the basis of the POD method, an attractor method and a stability analysis method,a damage diagnosis technology of an aircraft sheet structure under a supersonic speed condition is provided, and nonlinear tools such as a bifurcation diagram, Poincare mapping, a Lyapunov index, a stability domain boundary and a high-order POD mode are utilized to obtain the influence rule of the structural damage degree, the damage range and the damage position on aeroelastic response, and a setof nonlinear structural damage diagnosis tool with high sensitivity and a structural damage criterion are attempted to be determined.

Description

technical field [0001] The invention belongs to the field of non-linear structural damage diagnosis methods of aircraft, and in particular relates to an aircraft structural damage diagnosis method based on a stable boundary and a POD method. Background technique [0002] The thin-plate structure of aircraft with nonlinear flutter often suffers from fatigue damage due to long-term vibration, so damage detection is an important guarantee to ensure flight safety. The most common and effective existing structural damage diagnosis methods belong to the category of signal processing, which are mainly divided into: [0003] A. Vibration-based methods: Damage-induced changes in physical properties such as mass, damping, and stiffness cause detectable changes in modal parameters such as natural frequencies, mode shapes, and modal damping; [0004] B. Attractor-based approach; [0005] C. POD-based approach. [0006] For vibration-based damage detection, Rucka, M, Yam, L, etc. used...

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Problems solved by technology

[0008] In general, attractor-based methods and vibration-based methods use signal processing techniques to directly deal with structural responses, but there are two problems with this diagnostic technique: 1) The dynamic response of the system not only depends on the geometric and material properties, It also depends on the force and environmental conditions, and changes in force and environmental conditions may mask the dynamic response changes caused by structural changes, that is, structural damage; 2) structural damage is a typical local phenomenon that has little effect on the overall response of the structure , then the commonly used methods based on vibration and attractors for measurement and recording often lead to insignificant changes in dynamic response and detection failure

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