Liquid Applied Sound Damping for High Frequency Vibrations

摘要

The automotive industry is rapidly changing as electric vehicles (EVs) have gained share in the market, bringing new challenges to ensure passenger comfort through noise, vibration, and harshness (NVH) management. Automotive acoustics engineers employ a variety of materials to reduce NVH across the audible frequency spectrum. In general, these materials have been tailored to address vibrations related to internal combustion engines (ICE). For example, liquid applied sound damping (LASD) coatings are widely employed to reduce structural vibrations due to their ease of application and light weight. LASD coatings are typically applied to the vehicle body to reduce structural vibrations at frequencies <1000 Hz, since ICE vehicles tend to exhibit vibrational modes primarily at these frequencies. However, EVs are known to also excite higher frequency vibrational modes up to 3000 Hz. Additionally, the lack of masking noise from the engine may lead these noises to be more noticeable to the passengers than in previous vehicles. Consequently, it is anticipated that damping materials and their specifications may need to be adjusted to better mitigate these high frequency vibrations. Herein, we will examine the effects of LASD design on damping up to 3200 Hz, including formulation, polymer/filler interactions, and coating thickness. These results will guide design of next-generation LASD materials.