STATISTICAL ENERGY ANALYSIS AND DIFFUSE FIELD

International audience ; Statistical energy analysis (SEA) is a statistical theory of sound and vibration based on an analogy with thermodynamics. The main relationship of statistical energy analysis, the so-called coupling power proportionality, is intimately linked with the establishment of a diffuse vibration field in subsystems. In this study, we explore the conditions under which a diffuse field is enforced. We show that when the subsystem is excited by a point force, a low damping, a high frequency but also a ergodic billiard geometry are required conditions. Then, the energy exchange between two weakly coupled subsystems is proportional to the difference of vibrational energies. But when the field is not diffuse, the exchange of energy does not generally follow this proportionality. Numerical simulations are provided to support the discussion.