Research on adhesive layer depth and frequency in weak interface of bonded structures

Ultrasound is reflected from a bonded layer between two solid bodies. The reflection coefficient depends on the resonance frequency, the acoustic properties of different solids, the layer depth and the interface stiffness. In this paper, the parameters of the bonded structures are studied for evaluating the weak interface of the bonded structures and a numerical calculation is carried out. According to the relationship between the ultrasonic propagation characteristics and the reflection echo, the reflection coefficient of the bonding layer is derived by a single reflection and a multiple reflection approach. The numerical results show that the bonded interface can be evaluated using the depth of the adhesive layer, resonance frequency and the stiffness ratio.