An energy flow analysis between mechanical systems based on the second principle of thermodynamics

Several energy based methods, to approach noise and vibro-acoustic problems, are actually under development. These techniques provide a chance of describing the vibroacoustic behaviour of complex systems by the energies of a limited number of subcomponents. This process is the base of one of the most acknowledged methods in this field, i.e. the Statistical Energy Analysis (SEA). However SEA invokes only the first law of thermodynamics, i.e. the energy conservation principle. On the contrary it seems that the formulation of a complete theory of energy transmission among oscillators would claim also for the second principle of thermodynamics. Within this paper this direction of investigation, via the entropy concept, is developed leading to a theoretical power flow analysis employed to predict the energy behaviour of complex systems. Some classical SEA results are obtained as a special case of a more general approach.