An Effective Feature Extraction Method of Quantitative Recognition of Ultrasonic Echo for Bonding Quality of Composite Sheet

In this paper, a set of effective ultrasonic echo feature extraction method is proposed for the quantitative identification of thin plate composite bonding quality, which opens up a new research idea for the research of ultrasonic echo feature extraction for quantitative identification of thin plate bonding quality, and also lays a foundation for further quantitative identification of bonding structure debonding degree of thin plate. In addition to the time and frequency domain analysis, the empirical mode time-frequency analysis method is used to highlight the time-frequency characteristics of the echo signal, improve the resolution of the signal analysis, and expand the space for the echo signal feature extraction. The feature validity evaluation theory of fault diagnosis is introduced to evaluate the feature validity of high-dimensional signal parameters, and the invalid signal parameters are eliminated to obtain an effective echo signal feature set with low dimension. Using the exhaustive search strategy of feature selection theory, geometric distance measurement and information measurement evaluation criteria, and through the classification verification of support vector machine classifier, the effective feature vector for quantitative identification of adhesive quality is obtained.