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Extensional damping materials are commonly used in the automotive industry to control structure-borne noise. Using the dynamic properties of the material or composite panel, these materials can be represented in vehicle finite element or statistical energy analysis (SEA) models. However, in order to make the detailed design changes to the damping material treatment, proper characterization of the material properties is required. This paper discusses the method of measuring and validating the complex modulus of an extensional damping material using the Oberst beam technique [1]. Also, it is shown that the Ross, Kerwin, Ungar (RKU) analytical model can be utilized to predict damping of composite panels for SEA models [2]. SEA modeling of various composite panel constructions will be examined with supporting measurements.

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.