Compressive properties of graphite-embedded expanded polystyrene for vibroacoustic engineering applications

Abstract The transmission of low-frequency floor impact noises in buildings remains a longstanding problem to be solved. To design insulation materials for attenuating the low-frequency floor impact noises, a distinctive property with a dynamic stiffness that is low enough to achieve natural frequencies that are also sufficiently low, without an excessively low structural strength, is required. The mechanical properties of compressively deformed graphite-embedded expanded polystyrene foam were investigated and evaluated for the application to the low frequency insulation. In addition to the role of embedding graphite in decreasing stiffness, compression processing was shown to both reduce the dynamic stiffness and maintain the structural strength of the specimen, which provides an appropriate property for the application. This characteristic is assumed to be associated with the macroscopic deformation mechanics of closed-cell foam in response to compressive stress, which is distinct from that of open-cell foam or fibrous materials. The improved insulation performance of the compressively deformed specimen was verified through laboratory vibroacoustic tests. Moreover, based on the laboratory testing, the effect of changes in the structural wave fields on material optimization is discussed.