Guigne International Limited Paradise, Newfoundland Canada
The complex dilatational moduli of three closed cell foam materials and one elastomeric material were determined by mechanical excitation of thin samples. The neopreneEPTSBR, polyvinylchloride, and ethylvinylacetate foams had moduli that ranged from 0.2 MPa to 3 MPa in the 100-900 Hz frequency range. The decoupling performance of these materials was then determined by applying them to steel substrates that were mechanically excited, and measuring the effect of the coatings on the radiated sound. Unlike previous studies where the test plates were supported at the comers and semi-submerged, in this study the plates were clamped at the edges and backed by an airfilled concrete enclosure. This concrete box was submerged into a water filled tank and the radiated sound was determined by intensity mapping in the near field of the plate.