Abstract
Structure-borne traveling waves (SBTW) have been observed in nature as a source of propulsion and have been under study in recent years to drive particle motion. Experimental studies have found that steady-state SBTW can be excited in finite structures which are capable of driving propulsion. These SBTW have also been shown to provide the forces needed to drive the motion of particulates along the surface of the excited structure. The interest of this work is the trajectory of particulates when acted on by a novel combination of SBTW active in a thin plate. In previous work, individual traveling waves have been generated such that particulates were driven along an active material surface. But these studies have been focused on particulates reacting to individual SBTW. It has been shown that when two-dimensional traveling waves that propagate orthogonal to one another are superimposed, the resultant wave moves in a direction between that of the constituent waves. In addition to this, the direction of the resultant wave can be tuned by adjusting the relative amplitude and phase of the constituent SBTW. This work numerically examines the trajectory of particulates when acted upon by superimposed OTW. For this purpose, the Finite Element Method (FEM) is used to develop a model of a thin square plate with traveling waves generated using a two-mode excitation is developed. The particulates are then introduced to the system and assumed to have a mass sufficiently small so as not to influence the wave envelope. When different SBTW and superimposed OTW are generated in the plate, it is shown that the particulate can be made to move along the active surface with trajectories, depending on the excitation conditions and the friction coefficient between the particle and the plate. From this, it can be concluded that combinations of SBTW of this type can be tuned to drive controlled particle motion on an active surface.