Coupling loss factors between indirectly coupled machinery structures

The formulae for cajculating coupling loss factors between indirectly coupled structures of Which the coupling is strong or in the near field of the vibrating wave of the structures each other are derived by using two port method. The responses of the rotating machinery structures are predicted using the modified SEA balance equations with the indirect coupling loss factors and the agreement between the predicted and measured responses is better than those predicted by using the classical SEA equations.