New ultrasonic guided wave detection method

Abstract

The invention discloses a new ultrasonic guided wave detection method, which comprises: 1, constructing a Lorenz oscillator signal detection system; 2, calculating a Lyapunov exponent along with the change of a forced excitation signal amplitude value F in the case of no signal input; 3, inputting an ultrasonic guided wave signal modulated by a Hanning window into the Lorenz oscillator signal detection system, and calculating the Lyapunov exponent along with the forced excitation signal amplitude value F after inputting the ultrasonic guided wave signal; 4, selecting the forced excitation signal amplitude value F corresponding to the maximum absolute value of the different between two L1 as the excitation value of the detection system from the two corresponding areas having the two-L1 cross product of less than 0 in the system before and after inputting a standard ultrasonic guided wave signal; 5, exciting a detection object by using the ultrasonic guided wave signal, and obtaining a receiving signal through a receiver; and 6, inputting the receiving signal into the detection system having the selected forced power value, and determining the presence or the absence of the detect.

Description

technical field [0001] The invention relates to the technical field of detection, in particular to a novel ultrasonic guided wave detection method. Background technique [0002] Ultrasonic guided wave testing technology is a new type of non-destructive testing technology, which is very suitable for non-destructive testing of slender parts; however, due to the dispersion, multi-mode and attenuation characteristics of guided waves, in actual long-distance testing, if If the defect is small, the corresponding defect reflected echo signal is weak, but the background noise of the sensor, the inherent noise of the power amplifier, and the external interference noise are often much higher than the amplitude of the useful signal, so the reflected echo signal will definitely show The characteristics of weak signals under strong noise will seriously affect the identification and positioning of detection signals, thus affecting the accuracy of detection results. [0003] At present, t...

AI Technical Summary

Problems solved by technology

Since the guided wave signal is a multi-period signal modulated by the Hanning window, which is composed of several sinusoidal signals of different frequencies, when the traditional single-frequency chaotic oscillator is used to detect the guided wave signal, the multi-frequency characteristics of the guided wave signal will be It has an uncertain impact on the non-equilibrium phase transition law of the chaotic system, which is prone to misjudgment or misjudgment in theory

In addition, the chaotic oscillator models used in traditional chaos detection are all non-autonomous chaotic oscillators. Because their nonlinear characteristics and dynamic behavior are far weaker than those of autonomous chaotic oscillators, the sensitivity to weak signal identification is low.

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