POWER-FLOW CONTROL OF A THIN-PLATE

This paper deals with the active control of power flow of a vibrating plate. It is the purpose of this paper to present a wave control metho d for suppressing vibration of a distributed parameter system such as a beam or a plate. Unlike a conventional modal-based control method, t his method has the potential to suppress all vibration modes of a stru cture. First, from an analytical point of view, this paper presents th ree kinds of flow patterns appearing in controlled vibration intensity : (1) straight flow patterns from the excitation point to control poin t, (2) S-shaped flow patterns and (3) vortex flow patterns around the excitation point and control point. Then, the existence of these patte rns is verified experimentally. Next, relationships between vibrationa l and acoustical intensities are discussed, and the acoustic power and acoustic pressure in terms of these patterns are also investigated. F urthermore, the characteristics of the rotational patterns are clarifi ed and a means to generate the vortex of vibration intensity at an arb itrary position on a plate is presented.