Method for monitoring Lamb wave engineering structural damage by utilizing signal decomposition

Abstract

The invention discloses a method for monitoring Lamb wave engineering structural damage by utilizing signal decomposition, which comprises the following steps: collecting the Lamb wave healthy reference signals fhji of an engineering structure in a healthy state, wherein i and j can be 1, 2, 3,...; when the structure is damaged, collecting all the Lamb wave response signals f'ji of the damaged structure under the condition of an inspiring / sensing channel; utilizing the correlation operation to extract all the Lamb wave damage scattered signals of the damaged structure under the condition of the inspiring / sensing channel; obtaining the damage position and scope according to the characteristic parameters acquired in the steps above, thereby analyzing and judging the health condition of the monitored structure. According to the method, based on the condition of the traditional structural damage monitoring device, the Lamb wave damage scattered signals in a damage monitoring system are extracted by using the related treatment, thereby increasing the accuracy and stability of the monitoring system.

Description

technical field [0001] The invention relates to a method for active Lamb wave damage monitoring of plate engineering structures, in particular to a method for extracting Lamb wave structure damage scattering signals in active health monitoring so as to correctly realize engineering structure damage monitoring. Background technique [0002] With the continuous improvement of structural safety and reliability requirements, the on-line monitoring and diagnosis of structural damage has attracted more and more attention. In order to prevent disasters or losses caused by structural damage, effective monitoring of plate structures is necessary. [0003] The on-line monitoring of structural damage requires that the relevant signal generation and acquisition equipment should be relatively simple, and the monitoring must have high accuracy and real-time performance. The damage monitoring of plate structures generally adopts the method of active Lamb wave, that is, a certain number o...

AI Technical Summary

Problems solved by technology

Since the propagation of Lamb waves in the plate structure is non-directional, the method of directly subtracting the response signals before and after structural damage is mostly used to obtain the Lamb wave damage scattering signal. At this time, the piezoelectric element, signal power amplifier and data acquisition equipment Affected by changes in the environment and its own parameters will directly interfere with the correct extraction of damage scattering signals, and deviations will easily occur

This problem brings difficulties to the correct analysis of the acoustic wave propagation process and the extraction of characteristic parameters of the damage scattering signal, especially in the damage monitoring of composite plate structures, because the Lamb wave signal propagation is complex and the structure absorbs the signal quickly, so that This problem becomes more complicated

For example: At present, a large number of composite materials are used in the structure of the aircraft, and the structure is very complex. To study the online damage monitoring of the aircraft structure, the damage scattering signal must be correctly extracted first.

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