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Automotive engineering is taking a deeper look at the role of NVH engineering and design. Controlling the vehicle sound is one of the musts in designing successful automobiles today. While the focus is usually on powertrain noise, this report covers the concept of a new technology of dashmats. This new generation of dashmat is constructed of an absorptive layer, a barrier, and another absorptive layer (ABA). Typically, dashmats are placed inside the vehicle on the firewall between the powertrain and the driver. This dashmat blocks and absorbs powertrain noise as well as the vehicle background noise heard at the driver's ear. This report focuses on two types of competing dashmats-the light weight absorptive dashmat which acts by absorbing the sound rather than blocking it and the new generation of vehicle dashmat (ABA) which performs by blocking and absorbing the powertrain noise as well as the vehicle background noise.

Automotive body structures are developed to meet vehicle performance requirements primarily based on ride and handling, crashworthiness, and noise level targets. The body is made of a multitude of sheet metal stampings welded together. Other closures such as fenders, hood, doors and trunk lid are developed to match body interfaces, to contribute and participate in the overall vehicle response, and to meet the sub-system and system structural requirements. In order to improve performance and achieve weight reduction of the overall vehicle steel structure, new polymeric materials and treatment strategies are available to body structural engineers to optimize the response of the vehicle and to tune vehicle performance to meet specified functional requirements. If early integrated to the design cycle, these materials help not only improve the structural body response, but also decrease the weight of the integrated body structure.

Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material.