Method for locating blade cracks based on visual vibration measurement and nonlinear bi-coherence spectrums

Abstract

The invention discloses a method for locating blade cracks based on visual vibration measurement and nonlinear bi-coherence spectrums, and the method comprises the following steps of setting a plurality of position mark points on a crack blade, exciting the blade by using a random signal excitation method, and simultaneously obtaining non-linear vibration signals at each marker point position of the blade; calculating the squared bi-coherence spectrums of the corresponding marker point positions based on the non-linear vibration signals of each marker point position; calculating the non-Gaussian indexes of the corresponding marker point positions based on the squared bi-coherence spectrums corresponding to each marker point; calculating the non-linear indexes corresponding to each marker point according to the squared bi-coherence spectrums corresponding to each marker point; calculating the total non-linear index corresponding to each marker point according to the non-Gaussian indexesand non-linear indexes corresponding to each marker point; drawing a corresponding distribution map according to the non-linear indexes and total non-linear index corresponding to each marker point to determine the location of the crack. By adopting the positioning method provided by the invention, the recognition effect of the blade breathing crack position can be improved.

Description

technical field [0001] The invention relates to the field of blade structure breathing crack detection, in particular to a blade crack location method based on visual vibration measurement and nonlinear bicoherent spectrum. Background technique [0002] With the development of disciplines such as computer science, artificial intelligence and image processing, machine vision measurement technology has gradually become the most flexible and popular technology in the field of non-contact measurement, with the advantages of strong adaptability, wide measurement range, and multi-point measurement. [0003] The general vibration mode identification method is to obtain the free vibration response or impulse response of the structure by measuring the excitation and response signals, which is relatively easy for the laboratory model, but it is not easy for the health monitoring of the blade structure under the operating state of the natural environment , the blade structure is comple...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a blade crack location method based on visual vibration measurement and nonlinear bicoherence spectrum to solve the problem of low positioning accuracy of blade structure breathing cracks

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