Nonlinear ultrasonic guided wave detection system and method based on pwm code excitation

Abstract

The invention relates to a nonlinear ultrasonic guided wave detection system and method based on PWM coding excitation. The system comprises: a main control module, which is used for generating a PWM pulse modulation signal, receiving a feedback digital signal, and processing the digital signal to obtain a to-be-measured signal. The service life evaluation result of the material; the ultrasonic arbitrary waveform generator, which is connected to the main control module, is used to generate ultrasonic electric signals according to the PWM pulse modulation signal; the transmitter probe module is used to transmit the ultrasonic electric signal to the material to be tested under the excitation of the ultrasonic electric signal. Gaussian multi-period sinusoidal signal; the receiving end probe module is used to receive the ultrasonic guided wave signal fed back by the material to be tested, and convert it into a feedback electrical signal; the ultrasonic signal acquisition module, under the control of the main control module, is used for Sampling the feedback electrical signal and converting it into a digital signal; a multi-channel power supply module is used for power supply. Compared with the prior art, the present invention has the advantages of high signal-to-noise ratio, simple operation and the like.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing, and particularly relates to a nonlinear ultrasonic guided wave detection system and method based on PWM coding excitation, which utilizes non-destructive testing to evaluate the service life of materials. Background technique [0002] When ultrasound propagates in plate-like or tubular solid materials, it will have multiple reflections back and forth with the boundary of the waveguide, coupled with the conversion of ultrasonic transverse waves and longitudinal waves, and then generate guided waves. Nonlinear ultrasound is formed when the ultrasonic wave propagates in the medium due to the existence of the nonlinearity of the medium, resulting in the distortion of the waveform and the appearance of harmonic components on the signal. [0003] There are two common types of nonlinearity, one is the nonlinearity of the stress-strain curve of the material, which can be used for the eval...

AI Technical Summary

Problems solved by technology

The traditional method is realized by a digital-to-analog converter and a linear power amplifier. This method can improve the signal-to-noise ratio by increasing the amplitude of the transmission excitation signal, but requires the transmission system to work in a high-voltage state, which has high requirements for the system and improves the Design complexity and cost, and the system is bulky and complex to operate, making real-time data analysis difficult

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