力学可重构负刚度超结构的可调控水下声隐身性能OA

To address the urgent need for vibration and noise control and the enhancement of acoustic stealth performance of underwater equipment,a new approach was explored to achieve active regulation of the acoustic stealth performance of underwater functional structures using mechanically reconfigurable negative stiffness metamaterials.In this paper,two negative stiffness metamaterial unit cells with variations in band structure before and after mechanical reconfiguration were optimally designed.The evolutionary band characteristics during the deformation process of the unit cells were systematically analyzed.Homogeneous and graded plate/beam sandwich meta-structures with negative stiffness were constructed.Based on the structural-acoustic coupled finite element method,the underwater radiation noise's spectral characteristics of negative stiffness meta-structures under different combined configurations and preloading conditions were analyzed.The results show that the mechanical reconfigurability of negative stiffness metamaterials enables flexible tuning of wave propagation performance in meta-structures,while gradient sequences can broaden the sound insulation frequency band.This study provides theoretical and design references for developing lightweight underwater acoustic stealth and acoustic camouflage functional structures.