Title: Analyzing Effects of Upperbody on Road Noise of Platform-Sharing Vehicles
text: Platform sharing is widely used for reducing time and cost of vehicle development. It has been believed that vehicles that employ the same platform show similar performances of noise and vibration. Recently, however, it is observed that two vehicles that share the same platform present a noticeable difference in road noise. The structural difference between the two vehicles is located only at the upperbody of a Body In White (BIW). In order to investigate the effects of the upperbody on the road noise, several analyses such as (1) input point stiffness, (2) noise transfer function (NTF), and (3) road noise are performed using finite element (FE) models of the vehicles. As a result, it is found that the upperbody affects the NTF of the trimmed body and the road noise, which explains the dissimilarity of the road noise for the two vehicles. A novel method based on equivalent radiated power (ERP) is proposed to assess the upperbody. It is shown that analysis results obtained using the method show good correlation to the NTF of the trimmed body, which determines the road noise. Thus the proposed method can be used to assess an upperbody and predict the road noise of platform-sharing vehicles in the early stage of vehicle development.