Effects of Core Topology on Sound Insulation Performance of Lightweight All-Metallic Sandwich Panels

An analytical study of sound transmission through all-metallic, two-dimensional, periodic sandwich structures having corrugated core is presented. The space-harmonic method is employed, and an equivalent structure containing one translational spring and one rotational spring per unit cell is proposed to simplify the analysis of the vibroacoustic problem. It is demonstrated that the core geometry exerts a significant effect on the sound insulation performance of the sandwich, so that one may tailor the core topology for specified acoustic applications. Subsequent analysis of the sound transmission loss (STL) and dispersion curves of the structure leads to fundamental insight into the physical mechanisms behind the appearance of various peaks and dips on the STL versus frequency curves. As the weight, stiffness, and acoustic property of the sandwich structures all change with the alteration of core configuration and geometry, it is further demonstrated that it is possible to explore the multifunctionality of the structure by optimally designing the core topology.