Underwater Sound Insulation and Sound Radiation Characteristics of Honeycomb Sandwich Shells Considering Hydrostatic Pressure and Local Excitation

Lightweight honeycomb sandwich shells with excellent acoustic properties show promising application prospects in marine engineering. In this paper, a novel bidirectional re-entrant honeycomb sandwich shell (BRHSS) is proposed by introducing inclined ligament connections. A numerical acoustic-structure coupling model of the BRHSS is established to investigate its underwater acoustic performance. The influence of hydrostatic pressure on the sound transmission loss of the BRHSS is analyzed. Furthermore, the circumferential distribution of the radiated sound pressure level of the BRHSS under local excitation is examined. The results demonstrate that the proposed BRHSS exhibits better underwater sound insulation performance than the solid shell with an identical thickness within the investigated frequency range. The eigenfrequencies corresponding to sound transmission loss decrease with increasing hydrostatic pressure, leading to the shift of the high-frequency sound insulation band. The circumferential sound radiation distribution of the BRHSS is sensitive to the excitation frequency, which is governed by the circumferential vibration transmission characteristics under local excitation. Therefore, this study can provide useful guidance for improving the acoustic performance of underwater honeycomb sandwich shells by considering hydrostatic pressure and vibration transmission paths.