Sound transmission loss of an automotive floor panel section with cross members

Analyzing sound transmission loss (STL) of vehicle body panels is essential in assessing the noise trans-mitted into a vehicle. For a long time, floor panels have been assumed to follow the mass law perfor-mance with the effects of some cross members being ignored. In this paper, a typical automotive floor panel section with cross members is designed to understand how the sound transmission loss perfor-mance is affected by cross members. A hybrid analysis method was employed, in which the structure sur-face together with the 1-D acoustic space inside the cross members are represented by the boundary element modeling and finite element modeling respectively. Through various iterations, it has been shown that the cross member could affect panel STL significantly due to some lower order modes of the panel that are induced by the cross members and resonated acoustic modes inside 1-D acoustic spaces. Results are verified by in-situ STL measurements on a real vehicle. Finally, a sensitivity analysis was conducted based on the selected model to understand the contribution of each design variable to STL performance.(c) 2022 Elsevier Ltd. All rights reserved.