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In this report, two finite element models are presented which predict the vibration characteristics of metal/polymer/metal laminates. The first model uses an approximate elastic solution, while the second model uses a viscoelastic solution. A finite element preprocessor was created to implement both models. With this preprocessor, four complex geometries and a simple plate are investigated. Predictions are made for natural frequencies, damping values, and frequency responses. In addition, the predictions for the plate and one of the geometries is compared to experimental results. It is shown that the two models predict natural frequencies well, but bound experimental damping values. The conservative estimate of damping is given by the viscoelastic model. It is further shown that if the geometry of the component resembles a beam, that both models agree. Based on these observations, recommendations are made to exclusively use the viscoelastic model in design analysis.

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.

Multilayer Composite Materials, discussed in this paper, are defined as laminated structures consisting of two “Skins” of metal separated by a layer of polymeric material, applied as a coating, film or prepreg and adhesively bonded together. Such structures can be successfully manufactured in a continuous manner and this paper describes such composite materials utilized for sound and vibration damping over a wide range of frequencies and temperatures. With high damping properties [loss factor −ƺ (nu) ≥ .05] these materials can be formed and fastened by using existing equipment and technology, (including welding). This presentation is a result of a continuous 5 year effort to develop composite materials. Part of this development involving metal/polypropylene/metal structural composites was presented by H. H. Levine at the 1981 SAE Passenger Car Meeting. [1].