Vibration Transmissibility of Two-DOF Vibrating Systems

摘要

In most engineering applications, the vibration isolation problem, or vibration transmissibility, is studied using the one-DOF model due to its simplicity. In reality, however, if the vibration isolation system is mounted on a non-rigid structure or foundation, then it leads to a two-DCF vibrating system. A quite common case is a piece of rooftop equipment, such as fans and cooling towers, mounted on either springs or neoprene pads, because the roof structure itself is flexible and introduces the second degree of freedom. Occasionally, a piece of mechanical equipment is both internally and externally isolated which is also a two-DOF vibrating system. A floating floor and the structural floor also make a two-DOF system. This paper discusses the theoretical models of vibration transmissibility of two-DOF vibrating systems. A literature review is provided and errors in some references are corrected. Finite-element-models are developed to verify the theoretical analysis.