Cable fatigue damage detection method based on guided wave group velocity

Abstract

The invention belongs to the technical field of nondestructive detection and discloses a cable fatigue damage detection method based on guided wave group velocity; the method comprises the following steps of (1) carrying out cyclic loading on a standard test piece, acquiring a relation curve between the circulation loading frequency of the standard test piece and the wave guide group velocity, andtaking the relation curve as a calibration curve; (2) carrying out signal acquisition on a cable to be measured by adopting a guided wave instrument so as to obtain a time domain signal of the guidedwave, and then obtaining the propagation time of the guided wave according to the time domain waveform diagram of the time domain signal, and therefore obtaining the guided wave group velocity according to the propagation time of the guided waves and the propagation distance of the guided waves; and (3) judging whether the cable to be tested has fatigue damage or not on the basis of the calibration curve and the wave guide group velocity. According to the method, the fatigue damage detection of the cable is realized by measuring the wave guide group velocity, and the method is easy to implement, relatively high in detection precision and relatively high in applicability.

Description

Technical field [0001] The present invention belongs to the related technical field of non-destructive testing, and more specifically, relates to a cable fatigue damage detection method based on guided wave group velocity. Background technique [0002] Cable is the main stress structure of cable-stayed bridges, suspension bridges and other bridges. As the service life increases, bridge cables will experience fatigue damage in different procedures. It is of great significance to perform fatigue testing on them to ensure structural safety. At present, cable fatigue damage detection The main methods include nonlinear acoustic detection method, magnetostrictive guided wave detection method, etc. [0003] At this stage, those skilled in the art have done some research. For example, patent CN105806944A discloses a method and device for detecting cable fatigue damage. According to the comparison of the measured nonlinear acoustic parameters with the nonlinear acoustic parameters of standa...

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Problems solved by technology

[0003] At this stage, relevant technical personnel in the field have done some research. For example, the patent CN105806944A discloses a cable fatigue damage detection method and device. According to the comparison between the measured nonlinear acoustic parameters and the nonlinear acoustic parameters of the standard test piece, the cable fatigue damage is determined. Fatigue damage state; this method needs to analyze the signal in the frequency domain to extract the amplitude of the fundamental wave and the second harmonic, but the second harmonic is very weak, and the detection results are easily affected by the nonlinearity of the detection system, and the accuracy is relatively low Therefore, there is a technical demand in this field to develop a cable fatigue damage detection method based on guided wave group velocity with better detection accuracy.

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