Sound Insulation Characteristics of Honeycomb Sandwich Panels

The purpose of this research is to discuss the sound insulation characteristics of honeycomb sandwich panel. At first, the sandwich panel is made of layered media and the center core was regarded as an elastic porous material. Thus, the Biot theory could be employed to analyze the waves propagated in fluid saturated porous material. The transfer matrix for waves propagated between two ends of the sandwich panel was established. The combination of these related matrices can be applied to evaluate the transmission loss.
To order to verify the present method, four sandwich panels which were measured by Moore are analyzed. The comparison of the transmission loss between experimental data and numerical predictions is reliable except the Panel D. In the case of Panel D, the fundamental settings are different from present method in this thesis.
Using the present method, several cases are set up to investigate related parameters of cores, such as thickness, density and cell size. The numerical results show that the coincident frequency will change with different thickness of the core and this variance in frequency will influence the sound insulation of the panel. In addition, the effect of core density is similar to the effect of core thickness. The coincident frequency will decrease with the increase of the core density until the core density increase to exceed certain limit. At the time, the coincidence will occur in the same frequency. Finally, cell size of the core doesn’t influence the transmission loss of sandwich panels.