Abstract: In this paper, the measurement of dissipation and coupling loss factors for complex structures using an energy ratio method is presented. This method can be used for conservative, and non-conservative structures. The advantage of the method is to complete measurements of dissipation, coupling and indirect coupling loss factors of structures at the same time, not to know the mode densities of substructures.
Both the effects of resonant transmission and non-resonant transmission at lower frequncies on coupling loss factors are involved. The dissipation and coupling loss factors for a rotating machinery system had been measured using this method. Vibrating responses of the system are predicted using modified SEA balance equations and the agreement between measured and predicted results is fair.