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The performance of damping materials is generally evaluated by experimental methods. However most damping materials used in the transportation industry cannot be excited by itself. Therefore, the measurements are generally made by exciting a damped system, where the damped system extends from a bar to a panel. The paper reviews various damped systems and excitation methodologies and discusses some of the limitations of a bar to study the damping performance for different applications. It discusses a methodology where a damped panel is mounted on a fixture and the fixture is excited with a shaker. The paper discusses data acquisition and data reduction procedures to obtain the damping performance of laminated steel acoustic patch products on a third octave band frequency basis.

Noise transmission through automotive windshields is the subject of extensive laboratory acoustic and full scale high-speed track NVH evaluation. Standard windshields transmit structure-borne noise through resonances at low frequencies, and wind noise and airborne noise due to coincident effect at high frequencies. Approaches to enhance windshields NVH performance and to improve vehicle interior noise quality are explored. The study shows that the most effective approach is to design a new interlayer for windshields. This leads to the development of an acoustic grade PVB interlayer. To quantify the noise reduction by windshields with the new PVB interlayer, Solutia commissioned NVH testing of the windshields installed on cars, comparing these with factory-equipped standard windshields. Dynamic responses of the windshields were studied in laboratory on a dynamometer and resulting frequency response functions measured.