A Study of Compression Noise Isolation Mounts Constructed from Cylindrical Samples of Various Natural and Synthetic Rubber Materials

摘要

Transmissibility data are presented for a number of idealized compression mounts constructed from various types of rubber including Hevea (natural rubber), Hy-car OR-15, GR-S, GR-I-25, Neoprene FR, sponge rubber, a foamed rubber-like polyvinyl chloride, a material composed of rubber-bonded cork particles, and a high dampling rubber-like ethoxyline plastic. These data verify the existence of wave effects in the mounts. Values of the rubber constants at the fundamental resonant frequencies and at the several other frequencies are presented. Data showing the effect of strain amplitude on transmissibility are also included. The transmissibility theory previously reported is restated in a form valid for mount materials having high damping. Both transmissibility modulus and phase expressions are derived. An expression for the dynamic strain in the mount is presented. New nondimensional parameters for plotting complex transmissibility are suggested. In this report an attempt at establishing criteria for choosing mount materials is made based on optimum noise isolation, the possibility of constructing compression mounts capable of larger static deflections than the usual type is discussed, a criterion useful for evaluating mounts used on nonrigid foundations is proposed, and derivations of the particle equations of motion are presented for certain simple types of mounts. (Author)