Appropriate Damping Loss Factor of Vehicle Interior Cavity For Valid Application of Statistical Energy Analysis
By using a method of a previous study (SAE 2014-01-2081), sound transmission loss (STL) of vehicle panel structure could be calculated with an FEM model. The FEM model is consisting of the body in white, a hemispehere-shaped exterior cavity, and the interior cavity. The exterior cavity is excited and Statistical Energy Analysis (SEA) principle is applied for the calculation of STL of vehicle panel structure. It is known that SEA is a rapid and simple methodology for analyzing the complex vibroacoustic system. However, SEA principle is not always valid and one has to be careful about the physical conditions at which SEA principle is acceptable. In this study, the appropriate damping loss factor of the vehicle interior cavity is studied in the viewpoint of the modal overlap factor of the cavity and the decay per mean free path (DMFP) of the cavity. It is found that DMFP is appropriate between 0.5 ~ 1 dB for applying SEA principle.