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

摘要

A fundamental problem in the field of structure-borne sound is the characterization of dynamic sources with respect to vibrational power. Though one of the proposed approaches based upon the ability of a source to deliver power 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 system can be estimated. The analytical study considers methods of estimating the force ratios absolutely whilst the statistical study considers their statistical domain. For the analytical study all attempts in estimating failed under the condition of approximately equal point and transfer mobilities. With respect to the statistical part of the study, the mobilities and free velocities in a system are considered as "populations" and grouped functions are introduced to describe their distributions. Based upon these grouped functions, simple expressions are derived for the statistical distribution of the force ratios. A generalized approach is used throughout so that work is applicable to many systems.