Metal material crack quantitative monitoring method based on ultrasonic guided wave

Abstract

The invention relates to the equipment structure health monitoring field and discloses a metal material crack quantitative monitoring method based on a ultrasonic guided wave. The method comprises thefollowing steps of using a sensor network with a specific shape to carry out an excitation test on a metal material so as to obtain monitoring signals under different conditions; obtaining a damage index value through a damaged monitoring signal and a reference signal without damage; constructing a crack quantitative evaluation model of the metal material through a damage path probability imagingmethod; from monitoring imaging of a damage area of the crack quantitative evaluation model of the metal material, acquiring a slope of a straight line where a crack is located; setting a specific threshold, averaging coordinate values of discrete points which are greater than the specific threshold, and obtaining the coordinate values of the points through which the crack passes; acquiring an equation of the straight line where the crack is located through the slope of the straight line and the coordinate values of the points through which the crack passes; and through an intersection pointof the straight line and a damaged boundary line in a damaged imaging graph, acquiring end points of the crack. The method has advantages of being sensitive to small defects, having a large monitoringrange and the like.

Description

technical field [0001] The invention relates to the field of equipment structure health monitoring, in particular to a method for quantitatively monitoring metal material cracks based on ultrasonic guided waves. Background technique [0002] Metal materials are widely used in major equipment such as reusable aircraft and large lifting machinery. Metal structures are prone to cracks due to long-term repeated effects of stress or strain during service, which can lead to equipment damage and major safety accidents such as casualties in severe cases. [0003] At present, conventional non-destructive testing methods in engineering, such as: penetration testing, magnetic particle testing, radiographic testing, ultrasonic testing, eddy current testing, acoustic emission testing, etc., can be used to detect and locate fatigue cracks in metal structures, but these testing methods also have Its unique fields of application and limitations. For example, magnetic particle testing is l...

AI Technical Summary

Problems solved by technology

For example, magnetic particle testing is limited by the particle size of the magnetic powder, and can only detect surface cracks with a certain opening width; eddy current testing can only detect surface and near-surface cracks, and is not sensitive to deep-buried cracks; X-ray detection objects are usually volumetric damage ; Ultrasonic echo detection needs to scan the structure, the detection efficiency is low, and the reliability is not high when detecting closed cracks

In addition, during the implementation of the above detection methods, most of the external loads of the components to be tested are required to be released in advance, which affects the normal operation of the equipment; online real-time monitoring is difficult, which is not conducive to quickly ascertaining the structural state after an emergency, and then providing timely decision-making for maintenance support in accordance with

[0004] The above has the disadvantages of needing shutdown detection and low detection efficiency, and there may be missed detection of unreachable areas

In addition, the existing detection technology usually only realizes the qualitative detection of cracks, that is, it can only complete the location of cracks but cannot determine the size and direction of cracks, so it is impossible to perform safety assessment on structures

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