Damping materials for floor panels

Abstract

This paper describes the history of the development of typical damping materials for automotive floor panels from the introduction of asphalt sheet in Japan in 1963 until the present, as well as recent trends in the use of such materials. Technical developments in damping materials can be divided into the following four stages: (1) Noise reduction was attained by the effect of mass. (2) Elasticity was increased to improve the damping performance. (3) Constraining layers were added in the material (also to improve damping). (4) Weight reduction is being attempted; this is where the current research effort is being directed. A description is given of a resin constrained multi–layer–type damping material which maintains the same processability on the production line as is seen in conventional materials, while the damping performance is markedly improved.