Sound Insulation Characteristics of a Grid‐Stiffened Sandwich Structure with Local Resonators

Grid‐stiffened sandwich structures are widely employed in engineering applications owing to their superior mechanical properties. Nevertheless, their low‐frequency sound‐insulation performance is constrained by the surface mass density of the structure. In this study, a grid‐stiffened sandwich structure incorporating local resonators is proposed by integrating traditional grid‐stiffened sandwich designs and small‐scale resonators. An analytical model is established based on the space harmonic expansion method, and the sound transmission loss (STL) of the proposed structure is evaluated through both theoretical analysis and finite element modeling. The low‐frequency sound‐insulation mechanism is explained by analyzing the average normal displacement and energy flow power. The results show that the average normal displacement reaches a minimum value at frequencies close to the STL peak, and the energy flux power through the grid wall and air field is reduced by more than tenfold. The impacts of the material parameters, structural parameters, and sound wave incidence angle on the low‐frequency sound‐insulation performance are analyzed. Finally, the accuracy of the finite element modeling is verified via impedance tube sound‐insulation experiments. Consequently, this work provides a trigger for the design of multifunctional low‐frequency sound‐insulation structures.