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Commercial, electronics, aerospace, and automotive industries use a wide variety of methods to attenuate - damp - unwanted noises and vibrations. A well-established passive method for controlling structure-borne noise is based on viscoelastic materials that are specially selected for the application. In these cases, the materials are based on organic polymers that exhibit elastic and viscous properties. In the simplest cases, the damping material may be composed of a viscoelastic adhesive applied to one side of a suitable substrate. Expected performance for these layered assemblies of polymer-based coatings and supporting substrates is based on two factors: (1) the composition, quality, and durability of each coating; and (2) the composition, quality, and durability of each material-to-material interface. This is the second of two papers about this type of material for noise and vibration control.

In today's competitive efforts to continuously improve both material performance and quality, the “designer team” of laboratory scientists and engineers, manufacturing engineers, and marketing specialists must consider the ultimate cost of manufacturing at the very beginning of new product development. One method of controlling costs is by manufacturing new materials using continuous processing methods versus batch processing methods. Although continuous processing is not new to manufacturing, developing high performance material systems adaptable to such methods is still a challenge for chemists and engineers. This paper describes current R & D work to develop gasket materials which can be manufactured by continuous coating or continuous lamination of coiled substrates, e.g., metals, dense papers, etc. The focus of the paper is a discussion of work to relate material properties and performance to chemical structure of the gasket materials.

Continuous developments in car design and customer attention to performance and comfort have created necessities for improvements in external and internal noise reduction in cars, trucks and busses and thermal control around engine and exhaust areas. Solutions to these “challenges” are usually combinations of novel designs and selection of more efficient engineering materials. The authors describe the development of laminated composites consisting of outer metal “skins” with a specially selected core material between them. Depending on the noise damping and/or thermal insulation properties required by the application, the core materials may be viscoelastic polymers or inorganic materials.. As the result of this development, “families” of different materials for such applications are presented with the description of material properties and potential uses.

The authors describe the development and evaluation of a family of thin, laminated, material systems for use in noise and thermal control. The laminates are composed of thin, metal sheets which are interlayered with core materials specially selected for their thermal properties. The outer skins of the laminates in this study were typically 0.25-0.75 mm thick and were stainless steel, aluminized steel or aluminum alloy. A wide variety of core material compositions were evaluated including organic polymers, inorganic polymers, and refractory metal oxides. Likewise, the core materials were in various forms - woven cloths, felts, meshes, “papers” and mats, et cetera - and were typically 0.1-0.5 mm thick. After evaluating about 75 commercially available materials in a trade off study, a group of seven core materials were selected for further work. Key elements in the study were demonstrations of manufacturability and processability of the laminates.