Generation of circumferential harmonic travelling waves on thin circular plates

Abstract

A paradigm to generate harmonic circumferential travelling waves on a thin circular plate is proposed. The plate is considered to be connected to three circumferentially placed point actuators that excite the plate transversely with appropriate phasing. Uniform angular distribution of the actuators is observed to lead to wave locking at certain frequencies. The idea of angular detuning in the placement of the actuators is introduced to prevent wave locking. It is found that a simple kinematic phasing, which can generate travelling waves with uniformly distributed actuators, cannot be used in the case of non-uniformly placed actuators. An algorithm to calculate the phase detuning is proposed for a perturbed angular configuration of actuators for a smooth generation of travelling waves near any modal frequency. The mathematical model and the wave generation paradigm is validated using a finite element model developed in ANSYS. The results presented herein is expected to be helpful in studying the mechanics of wave-based transport of granular materials interacting with such surface travelling waves.