Damage detection method for thin-wall structure

Abstract

The invention relates to the field of modern aircraft large-size thin-wall structure damage detection, in particular to a thin-wall structure damage detection method. Response signals of N (N-1) paths of Lamb waves and reference signals of the N (N-1) paths of Lamb waves are obtained; determining a damage scattering signal based on the response signal and the reference signal; performing noise reduction on the damage scattering signal through an over-complete dictionary; determining the damage probability of the L * M virtual units according to an OMP algorithm, and obtaining N (N-1) damage elliptical bands through probability imaging; superposing or multiplying the N (N-1) damaged elliptical bands to obtain the damage probability of the L * M virtual units, and obtaining a thin-wall structure damage image through probability imaging; according to the embodiment, qualitative judgment and quantitative judgment of the damage position are achieved, and the result is more accurate and specific.

Description

technical field [0001] The invention relates to the field of large-scale structure damage detection of modern aircraft, in particular to a thin-walled structure damage detection method. Background technique [0002] Affected by dynamic / static loads, working conditions, material properties, and external factors, modern aircraft structures tend to have performance degradation trends and more serious structural damage, which affects their normal work and may further cause safety hazards, and even It was a catastrophic accident. In addition, in the stage of aircraft design and manufacture, because it is difficult to accurately predict the distribution of factors affecting structural life in service, even the most perfect design is difficult to avoid the risks brought about by changes in service conditions. As people's requirements for the safety, reliability and economical operation of modern aircraft are becoming more and more prominent, the development of a reliable and effic...

AI Technical Summary

Problems solved by technology

However, the traditional OMP algorithm can only achieve small damage imaging, the main reason is that for a few pixels in a small area, due to the relatively small distance, the propagation time difference of the Lamb wave is almost equal to 0, resulting in In order to achieve the sparse representation of the signal by finding the best matching atom when the OMP algorithm is used, only one pixel can be obtained in the corresponding area as the main damaged pixel. point, ignoring other possible damaged pixels

Therefore, through the traditional OMP algorithm, the pixel points must be equal to the size of the damage in order to better realize damage localization imaging, which results in low imaging accuracy; and when the pixel points are small, it is difficult to realize the detection of existing damage in the structure. Lesion Imaging in Larger Lesions

Images