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Liquid spray applied damping materials have potential advantages over conventional sheet damping materials in automotive body panel vibration applications. In order to understand the acoustical impact, a laboratory based NVH study was conducted to compare the damping and stiffness performance characteristics of various sprayable damping materials versus the production damping treatment. Based on this comparison, a criteria was developed to select potentially viable sprayable damping materials for vehicle testing. In-vehicle tests were also performed and compared to the laboratory findings to understand how well the results correlate. This paper discusses a criteria for selecting sprayable damping materials based on bench-top tests for vehicle applications, and the potential benefits of sprayable materials.

The automobile's interior acoustic treatment must provide sufficient sound absorption to enhance the conversational ability between the vehicle's occupants under all driving conditions. Addressing this increasingly important customer driven requirement becomes even more challenging in larger vehicles like minivans. Several factors affect clear conversation (Speech Intelligibility) and include: the reverberation/absorption characteristics of the environment and the type and intensity of ambient noise. This paper discusses the effects of major interior trim components on the reverberation characteristics of a minivan interior environment and their impact on speech intelligibility. Among interior trim components, seats have been found to be the major contributor to a vehicle's interior sound absorption. Various component and in-vehicle test results are presented to exemplify the effects of seat constructions on speech intelligibility.

Body cavity fillers are used to inhibit noise propagation/amplification through body cavities such as sills, pillars, and posts' to improve vehicle NVH performance. Cavity fillers should be optimized by matching their performance with the global NVH objectives of the vehicle. A standard test method must be defined to acquire acoustical profiles and facilitate in the proper selection of materials based on performance. This paper discusses test results of 38 cavity filler samples which represent all currently used materials by the “Big Three” automotive OEMs. The samples were grouped into 4 categories based on their weight and fill configurations. Data was obtained utilizing an established, laboratory based, acoustical test method for fillers (SAE paper 930336). The laboratory results were analyzed to generalize the performance of cavity filler materials and to set acoustical goals for vehicle applications.