Bioinspired Scraper-File Type Frequency-Doubling Ultrasonic Exciter

Abstract

In the natural world, leaf-cutting ants cause vibrations through their mutual scraping of file-scraper organs. In this study, we designed a Biomimetic Ultrasonic Exciter (BUE) that imitates leaf-cutting ants. The operating characteristics of the BUE were studied through experimental testing and finite element simulations. The results showed that the BUE could generate stable ultrasonic vibrations, and that the excitation frequency only needed to be half the Output Frequency (OF). This frequency-doubling phenomenon was conducive to achieving BUE miniaturization. To further explore the phenomenon of frequency-doubling vibration output, this study designed scrapers of five different sizes, conducted excitation and first-order natural frequency measurement tests, and the corresponding finite element simulations. It was found that each scraper could operate in frequency-doubling mode, but the operating frequency and natural mode frequencies did not correspond with one another. To further explicate experimental and simulation results, a two-degrees-of-freedom vibration model was developed. It was evident that the contact relationship between the dentate disc and scraper introduced strong nonlinear factors into the system, accounting for the frequency-doubling phenomenon and the difference between the BUE’s operating and mode frequencies. The BUE could be expected to facilitate the production of high-power micro-ultrasonic generators and has potential application value in the fields of mechanical processing, industrial production, and medical health.