Power transmission from two coherent machines to a dual-layer coupling floor structure

Several coherent machines are often installed on multiple layers of a coupling floor structure within a building. This paper reports on a study of the effect of the interaction between two such vibratory machines on the power transmitted to a coupling dual-layered floor plate and the level of power transmissibility. The study is based on a model of two rectangular machine models of even-mass distribution with four symmetrical supports; the mobilities of a simply supported concrete floor and dual-layered plate structure are computed using a Finite Element Analysis simulation. The results show that the total structure-borne sound power transmitted from either two coherent machine sources or an independent source to a coupling floor structure differs considerably from that emanating from an independent machine source on a single simply supported plate. This is especially true at certain strong coupling modes in the vibration isolation region. To predict the performance of vibration isolation more accurately, the power transmissibility method needs to consider the effect of effective floor mobility and the interactions of the mounting points of the independent machine sources, as well as the interactions of the mounting points of different machine sources, on a coupling floor structure.