New floating floor design with optimum isolator location

In this paper, a new design concept of an isolated honeycomb floor with a special arrangement of isolators is proposed to improve the vibration isolation performance of conventional lightweight cement floor panels in the frequency range of 120-600 Hz. The symmetric bending resonance frequencies and mode shapes of a honeycomb floor panel were identified by a shaker test. The effects on vibration isolation of isolator position and acoustic insulation were then investigated using experimental modal analysis. The analysis suggests that four design features ensure the optimum vibration isolation performance of a square floating honeycomb floor: the floor panel should be small, stiff, and lightweight; the isolators must be placed at the nodal points of the symmetric bending modes of the floor panel; the vibration must be transmitted via the center point of the floor panel; and acoustic insulation material should be installed inside the cavity. The proposed floating floor design achieved a vibration reduction of 20-30 dB in the frequency range of 120-600 Hz. In addition, the proposed floor was found to have a 20 dB lower vibration level at the first bending resonance frequency than the conventional design with isolators that are placed at the edges. (c) 2007 Elsevier Ltd. All rights reserved.