Structure-borne sound power and source characterization in multi-point-connected systems. Part 3: Force ratio estimates

A fundamental problem in the field of structure-borne sound is the characte rization of dynamic sources with respect to vibrational power. Though one o f the proposed approaches based upon the ability of a source to deliver pow er is promising, it necessitates estimating the spatial distribution of the forces at the multiple contacts between the source and receiver structure. Hence, by way of both an analytical and a statistical study, in this paper methods are investigated through which the force ratios manifested in a sy stem can be estimated. The analytical study considers methods of estimating the force ratios absolutely whilst the statistical study considers their s tatistical domain. For the analytical study all attempts in estimating fail ed under the condition of approximately equal point and transfer mobilities . With respect to the statistical part of the study, the mobilities and fre e velocities in a system are considered as "populations" and grouped functi ons are introduced to describe their distributions. Based upon these groupe d functions, simple expressions are derived for the statistical distributio n of the force ratios. A generalized approach is used throughout so that th e work is applicable to many systems. (C) 1999 Academic Press.