A Time-Frequency Research for Ultrasonic Guided Wave Generated from the Debonding Based on a Novel Time-Frequency Analysis Technique

• Main Authors: Junhua Wu, Zheshu Ma, Yonghui Zhang
• Format: Article
• Language: English
• Published: Hindawi Limited 2017-01-01
• Series: Shock and Vibration
• Online Access: http://dx.doi.org/10.1155/2017/5686984
• ISSN: 1070-9622; 1875-9203

Carbon fibre composites have a promising application in the future of the vehicle, because of their high strength and light weight. Debonding is a major defect of the carbon fibre composite. The time-frequency analysis is fundamental to identify the defect on ultrasonic nondestructive evaluation and testing. In order to obtain the instantaneous frequency and the peak time of modes of the ultrasonic guided wave, an algorithm based on the Smoothed Pseudo Wigner-Ville distribution and the peak-track algorithm is presented. In the algorithm, a masking step is proposed, which can guarantee that the peak-track algorithm can automatically exact the instantaneous frequency and the instantaneous amplitude of different modes on the Smoothed Pseudo Wigner-Ville distribution. An experiment for detecting the debonding for a type of carbon fibre composite is done. The presented algorithm is employed on the experimental signals. The processed result of experimental signals reveals that the defect can stimulate new modes, and there is a quantitative relationship between the defect size and the frequency of the new mode. The presented technique provides a valuable way to detect the presentence, calculate the size, and locate the position of the debonding defect.