Parameter accurate quantized detection method for debonding defect of carbon fiber reinforced composite board through single mode ultrasonic guided waves
A technology of ultrasonic guided wave and composite plate, which is applied in the direction of using sound wave/ultrasonic wave/infrasonic wave to analyze solids and process detection response signals, etc. It can solve problems such as difficult to extract defect information and complex detection signals
Inactive Publication Date: 2012-06-20
BEIJING INSTITUTE OF TECHNOLOGYGY
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The combined effect of the three characteristics makes the actual detection signal very complicated, and it is difficult to extract defect information
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[0018] The specific embodiment of the present invention is described in detail below:
[0019] The Wigner-Ville distribution is one of the important tools for analyzing non-stationary time-varying signals. It solves the problems of STFT to a certain extent. It is defined as the Fourier transform of the signal center covariance function. In order to improve the time aggregation, the Wigner-Ville distribution of the signal can be smoothed by windowing, and the new distribution obtained is called Pseudo Wigner-Ville Distribution (Pseudo Wigner-Ville Distribution, PWVD for short). Different from STFT's linear representation of signals, PWVD is a quadratic time-frequency representation of signals, which is more adaptable to non-stationary ultrasonic guided wave signals, and can obtain more accurate guided wave video distribution information.
[0020] The PWVD transformation operation of the guided wave signal f(t) can be expressed as follows:
[0021] PWD ...
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The invention relates to a parameter accurate quantized detection method for the debonding defect of a carbon fiber reinforced composite board through single mode ultrasonic guided waves. As the transmission mechanism of the ultrasonic guided waves in the composite board has not yet been clearly recognized, the existing main method for detecting the debonding defect of the composite board through the guided waves is to infer the influences of the composite board debonding defect on the guided waves of each mode based on a portion of given guided wave transmission characteristics, and to find characteristic parameters capable of typifying degree of the debonding defect to act as the standard for the defect quantification through combining a large number of experiments. The given influences of the debonding defect on the guided wave transmission characteristics include the attenuation characteristic, the frequency dispersion characteristic, the mode conversion characteristic and the like, wherein the attenuation characteristic is presented as the energy change of the guided waves, the frequency dispersion characteristic is presented as the time domain spread of a wave packet, and the model conversion characteristic is presented as the conversion from a single mode signal to a multimode signal. The joint action of the three characteristics results in the extreme complexity of the detection signal in practice, and the difficulty of the defect information extraction. However, through extraction of the single mode signal and inhibition of the frequency dispersion characteristic of the single mode signal, the amplitude variation information of the single mode guided waves caused by the defect can be stressed, and the characteristic parameters of the defect can be extracted conveniently.
Description
1. Technical field [0001] The invention relates to a single-mode ultrasonic guided wave parameter accurate quantitative detection method for the debonding defect of a carbon fiber reinforced composite plate. 2. Background technology [0002] Since the propagation mechanism of ultrasonic guided waves in composite panels has not been fully understood, the current main method for guided wave detection of disbond defects in composite panels is to infer the impact of disbond defects in composite panels on the basis of some known guided wave propagation characteristics. The influence of each mode of the guided wave is combined with a large number of experiments to find out the characteristic parameters that can characterize the size of the debonding defect as the standard of defect quantification. The currently known effects of debonding defects on the propagation characteristics of guided waves include: attenuation characteristics, dispersion characteristics, and mode conversion ...
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IPC IPC(8): G01N29/44G01N29/04
Inventor 徐春广许寒晖肖定国周世圆赵新玉郝娟孟凡武潘勤学王立久
Owner BEIJING INSTITUTE OF TECHNOLOGYGY