Research on the Transmission Characteristics of Underwater Bonding Structure in Oblique Incidence

The acoustic model of three-layer bonding structure in water when oblique incidence is established,the acoustic impedance method and spring model are used to derive the representation of transmission coefficient of three-layer bonding structure when oblique incidence;and the numerical simulation is done to analyze the influence of the incidence angle,the adhesive thickness,the steel plate thickness,the substrate materials on the transmission coefficient;at the same time,the influence of the change in stiffness coefficient on the transmission coefficient of the weak bonding structure is studied.To verify the theoretical derivation,the experiment on the three-layer bonding structure(steel-epoxy-steel) in water when oblique incidence is done,the test results are in good agreement with the theoretical results.The results show that,the changes in incidence angle and other parameters will cause the change of resonant frequency points or the peak of transmission coefficient;the bonding structure is weak bonding structure when the stiffness coefficient is small,there is more than one peak of transmission coefficient,and the phenomenon of more than one peak is disappeared when good adhesion.