Title: Study of the Glass Contribution to the Interior Acoustics of a Car and Related Countermeasures
text: This paper shows that the combination of a glass and passive acoustic treatment manufacturers can bring different benefits and considerably improve the interior acoustics of a vehicle. Glazing contributes to the design of the vehicle in addition to its primary role, good visibility and safety. From an acoustic point of view, this brings a challenge for the interior comfort. Indeed, glazing has no absorption and classically has an acoustic insulation weakness around its coincident frequency. In most of the cases, these different aspects make glazing one of the main contributors to the sound pressure level in the passenger compartment, and the trend is not one of change. However, there are possible countermeasures. One of which is the use of laminated glazing with acoustic PVB. This solution allows reducing the loss of insulation performance at the coincidence frequency. The other is the usage of passive interior acoustic trims. When properly positioned and optimized, the latter can be very effective and can tackle the frequency range that poses a problem. Especially since some technologies allow, by their process, to choose between the improvements of insulation or absorption. The aim of this paper is to understand the impact of the glazing on the interior acoustic for tires excitations. For that study, a measurement campaign together with some simulations models (FE and SEA) have been carried over on a European C-segment vehicle. A ranking of the different contributions is proposed. Then, in a second part, the countermeasures to improve the interior sound pressure level by adding optimized glazing and sound packages are presented.