Compressive Wave Isolation of Lightweight Equipment Very Close to a Vibration Source Using a Rubber Sheet

Protecting sensitive and/or valuable facilities is of concern when placing them near a machine foundation. There are methods available and well-studied such as wave barriers to reduce transmitted vibration and noises in the vicinity of a vibration source. Wave barriers are feasible to protect objects that are far enough from the vibration sources but are not practical to protect any facilities that are very close. In regions very close to the vibration source, body waves are dominant and carry most of the energy of the propagated wave, but at greater distances, Rayleigh waves are predominant and wave barriers become feasible. In this study, a rubber sheet is placed between a vibration source and nearby lightweight equipment (NLE). This has allowed assessment of this technique as a potential means of isolating NLE from machine foundations that are sources of vibration. The dynamic response of the machine foundation and NLE has been evaluated by conducting a series of vertical steady-state vibration tests. It was observed that by isolating a vibration source using a rubber sheet, the resonant frequency of the source and the NLE decreases. This is desirable when it displaces the resonant frequency away from the working frequency. Moreover, a considerable reduction of the vertical amplitude of NLE was observed in the optimal frequency range of 40–50 Hz by isolating the vibration source by using 12 mm of rubber sheet.