Abstract

Measurement of the structure-borne sound energy flow through pipes has been studied for the purpose of transmission path ranking. This paper describes the measuring methods for frequencies below the cut-off frequency of the n = 2 shell mode. The methods show a strong analogy with the two-microphone cross-spectral density method for airborne sound intensity measurements. Experiments on two lightly damped pipe sections of a cooling water circuit are used to illustrate some practical measuring aspects and some procedures for error analysis. Reasonably accurate measurements appear feasible, provided high quality instrumentation is used and the various wave types are separated carefully.