Sound Transmission Loss Analysis and Improvement of Honeycomb Sandwich Panels Under General Constraint Boundaries

Honeycomb sandwich panels (HSPs) are extensively applied in numerous industrial fields due to their advantages such as low density and high strength. In scenarios like aerospace and rail transit, where noise control requirements are stringent, the sound insulation performance of HSPs has garnered significant attention. To establish a vibro-acoustic model of HSPs under general boundary constraints and clarify the effects of structural parameters and boundary conditions on their Sound Transmission Loss (STL), this paper derives the energy functional of HSPs based on the First-order Shear Deformation Theory (FSDT) and the equivalent mechanical model of honeycombs. The governing equations of the system are established via Hamilton’s principle, and a semi-analytical solution is obtained using the improved Ritz method. Distinguished from traditional approaches, this paper employs the virtual spring technique to simulate general elastic boundary constraints, enabling precise modeling of various complex engineering scenarios. Simultaneously, a modified shear correction factor is introduced to replace the conventional fixed value, thereby improving calculation accuracy for soft-core structures. The accuracy of the proposed model is further validated through numerical examples. Through parametric analysis, the influence of boundary stiffness, honeycomb wall thickness, cell side length, and core height on STL is elucidated. Finally, to address the poor low-frequency sound insulation, an electromagnetic shunt damping strategy based on a Negative Inductance Negative Resistance (NINR) circuit is proposed to enhance the insulation potential in the resonance region. By optimizing the relevant circuit parameters, the sound insulation performance of the panel is significantly improved, and the effective insulation bandwidth is broadened.