Indirect methods to determine the mobility of structure-borne sound sources

摘要

Structure-borne sound sources can be characterized in terms of activity (e. g. free velocity)rnand structural mobility. Measurement of mobility is often associated with practical difficulties,rnas the source has to be freely suspended and carefully excited at each contact point.rnMoreover, the mobility of the source might change when installed, due to additional restraintsrnor non-linear elements. For these reasons, it can be advantageous to obtain the source mobilityrnin-situ. This paper presents methods to indirectly determine the mobility of a sourcernstructure. The methods involve measurement of a receiver structure, typically a receptionrnplate, with and without the source of interest attached to it. From the difference between therntwo measurements, the source mobility matrix can be derived. The theoretical derivation ofrnthe methods is followed by a numerical validation using simulations of SDOF and MDOFrnsystems. For the experimental validation, case studies were performed with different sourcernstructures, ranging from a simple mass to a representative multi-contact machine. Resultsrnare presented, and the potential and challenges of the proposed methods are discussed.