Investigating the use of dynamic sub-structuring methods in predicting floating floor performance.

Abstract

Floating floors are a common means of reducing airborne and structure-borne noise, however, prediction of in-situ performance remains a challenge for many consultants. The specification of such floors, usually based on single degree of freedom assumptions, does not account for the influence of floating floor dynamics, dynamics of host structures or interplay/power flow between the two via the isolating mounts. Reliance on single degree of freedom systems tend to over-predict the performance of the floating floor element, often leading to noise/vibration issues in the finished construction. A more robust approach is needed, though is challenging due to complexities in characterising large-scale constructions, where source-to-receiver Frequency Response Functions (FRFs) must account for multiple points of contact between floating and structural elements. This paper first presents a hybrid method for evaluating the source-receiver FRF of a simple floating floor via a sub-structured approach, and confirms the validity of the method to that of the source-receiver FRF measured directly. Efforts to simplify the analysis to a set of engineering-grade operations is also presented, the aim being movement towards a methodology that can be more readily utilised by practitioners, without the need for expensive modelling software or high end hardware setups.