A procedure for mapping vibrational power flow through a frame structure is presented. The vibration field in any structure can be decomposed into two components: a "standing" component corresponding to the kinetic/potential energy entrained in the structure, and a "traveling" component corresponding to the vibrational energy flowing through the structure. The latter is controlled by internal and external damping, and by the availability of alternate paths through the structure. It is shown that the power flow through a structural element can be established by measuring tangential components of a "generating vector" {a} along its boundary. This method is demonstrated for the flow of bending and torsional energy through a beam/plate. Two finite-difference approximation methods are compared, and it is shown that when the standing component is much larger than the moving component, even small phase mismatches between transducers of large arrays may seriously degrade the estimation of power flow.
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