Enhanced Windshield NVH Modeling for Interior Cabin Noise

The windshield is an important component in vehicle NVH performance. It plays an integral role in affecting the interior cabin noise. The windshield acts as a large panel typically oriented near vertical at the front of vehicle’s acoustic cavity, hence modeling it appropriately is key to have a reliable prediction of cabin interior noise. The challenge of modeling the windshield accurately rises from the structural composition of different types of windshields. For automotive applications, windshield come in several structural compositions today. In this paper, we will discuss two types of windshield glass. First is a typical laminated glass with polyvinyl butyral (PVB) layer and second is a typical acoustic glass with PVB and vinyl layers. Acoustic glass improves acoustics characteristics of the glass in frequencies of ~ 1200 Hz to ~4000 Hz range. Low frequency interior cabin noise studied with FEA is typically below 500 Hz. The acoustic glass doesn’t provide any benefits in this range and in many cases we see an adverse contribution at lower frequencies since the acoustic windshield tend to be softer. In this paper, frequency dependency of PVB layer and acoustic vinyl layers are investigated. Multiple modeling techniques for windshield are demonstrated and the results are compared to physical tests. Finally an enhanced windshield modeling technique for low frequency interior cabin noise is proposed.