Integrated design of Low-Frequency circumferential acoustic stealth composite structure under Deep-Water wave incidence

With the shift toward lower frequencies in active sonar systems, conventional acoustic coatings struggle to achieve efficient attenuation of meter-scale low-frequency sound waves within confined centimeter-scale thicknesses. To address this challenging issue in the domain of underwater acoustics, a novel embedded large-scale active–passive composite acoustic plate has been developed. Designed with Fx-LMS active control theory, this composite structure integrated giant magnetostrictive materials (GMMs) embedded in a viscoelastic rubber substrate. Through the structural design, electromagnetic system analysis, radiate plate shape optimization, and boundary constraints simulation, the vibro-acoustic performance of the active control unit was enhanced. Meanwhile, the peak source level of single active control unit exceeded 150 dB and the lower limit of the operational frequency range was expanded to 236.37 Hz. Based on different array topology configurations, combined with the theory of low-frequency phased arrays, an optimal layout was derived for large-scale plates. The circumferential active acoustic stealth performance of optimal configuration under oblique incidence conditions was further explored, demonstrating effective noise reduction exceeding 10 dB for narrowband oblique incidence within ± 30°. The secondary noise increase in the non-controlled regions was effectively suppressed by over 5 dB. This active–passive composite thin-plate provides a novel approach for acoustic field regulation and noise suppression of underwater vehicles, demonstrating certain scientific and practical value.