Study on Calculation Method of Underwater Sound Vibration of Sandwich Plate under Double-Sided Hydrostatic Pressure

With the increasing working depth of submarines, composite sandwich panels with lattice-reinforced columns and cavities are gradually applied into external shell structures due to their excellent characteristics of high strength and designability of acoustic vibration performance. In order to establish an underwater acoustic vibration calculation method for composite sandwich panels with lattice-reinforced columns and cavities considering double-sided hydrostatic pressure, the effect of high hydr-ostatic pressure on the acoustic vibration performance of the internal water-filled structures such as the enclosure shell under high diving depth is studied. Firstly, the multi-level homogenization equivalence method is used to treat the core layer of the submerged composite sandwich panel with reinforced columns and cavities as an orthogonal anisotropic material to obtain a homogeneous sandwich panel model. Secondly the transverse double-sided hydrostatic pressure is treated as the circumferential homogeneous load based on the strain energy density equality, and the underwater vibration equation of the homogeneous sandwich panel based on the LW theory model is modified. A method is proposed to calculate the underwater acoustic vibration of composite plate with lattice-reinforced columns and cavities considering the two-sided hydrostatic pressure. Finally, the accuracy of the method is verified using by numerical calculation methods. It is found out that the theoretical solution agrees well with the numerical solution. The method can predict the effect of two-sided hydrostatic pressure on the acoustic vibration performance of composite sandwich panels with lattice-reinforced columns and cavities accurately.