VIBRATION PROPERTIES OF SANDWICH INJECTION MOLDINGS

This paper presents the vibration damping of a sandwich plate fabricated by the sandwich injection moldings. The sandwich plates used in this work consist of polystyrene (PS), or polycarbonate (PC) as a skin layer and two different kinds of elastomer (FL or TH) as a core layer. FL is the elastmer in polyester group, and TH is the elastmer in olefin group. FL has more excellent adhesive property for the two skin materials, as compared with TH. Vibration tests were performed to obtain the logarithmic damping factor, by applying an impulse with a hammer on the central portion of the plate under the perfect free boundary condition. Also the relationship between core volume fractions and the damping properties were measured. It was found that PS/FL had the highest vibration damping in the plates with PS skin layers, whereas TH has higher damping property than FL. The rate of increasing in vibration damping was larger in PS/FL than in PS/TH, with increasing volume fraction of core material. The above results indicate that the adhesive property between core and skin layers makes a great influence on the damping property of the sandwich plate.