Subharmonic vibrations in plates excited by high-intensive ultrasonic pulses

In this paper, the experimental and theoretical studies on the excitations of the subharmonic vibration in metal plates by the intensive ultrasonic pulses injected via an ultrasonic horn are presented. A series of experiments is performed to study the subharmonic vibration behaviors of rectangular stainless steel plates. The experimental results show that the excitations of the subharmonics change remarkably with different materials, sizes and fix (boundary) conditions of the plates, as well as the preload forces between the horn and plate. Meanwhile, a vibro-impact dynamical model is put forward to explore the generation mechanism of the subharmonics in the plates. According to the model, the intermittent contact between horn and plates is the reason for the generation of subharmonic vibration in plates. The numerical results are in agreement with the subharmonic phenomena observed in the experiments.