Energy reflection and transmission characteristics of longitudinal wave in multilayer structure

The study on the energy reflection and transmission mechanism of ultrasonic waves in adhesive structures is very important. In view of this issue, the interaction between the ultrasound and the interface under the longitudinal wave incidence at different angles was discussed when the plate-like adhesive structure interface was intact. Besides, the influence of the change in frequency-thickness product on the energy reflection and transmission characteristics of sound wave was analyzed. The numerical results showed that the wave conversion does not occur when the longitudinal wave is incident perpendicularly, and the obvious periodic resonance appears in the energy reflection and transmission coefficient curve of longitudinal wave with the increase of frequency-thickness product. When the longitudinal wave is incident obliquely, the wave conversion will occur, and there is no periodic resonance phenomenon in the energy reflection and transmission coefficient curve of longitudinal wave and transverse wave with the increase of frequency-thickness product. The research results provide a theoretical basis for the ultrasonic inspection of adhesive structure in experiment.