A Strategy for Delivering High Torsionality in Longitudinal-Torsional Ultrasonic Devices

Abstract

A composite longitudinal-torsional vibration mode has applications in ultrasonic motors, ultrasonic welding and ultrasonic drilling. There are two ways to obtain this vibration behaviour using a single transducer, namely (i) coupling of a longitudinal and a torsional mode, which is known to be difficult; and (ii) degenerating a longitudinal mode to deliver longitudinal-torsional behaviour at the horn tip. A mode-degenerating horn is achieved by incorporating helical or diagonal slits in an otherwise traditional exponential horn driven by a Langevin transducer. However, it is often difficult with this configuration to avoid coupling of unwanted bending modes, low responsiveness, and loss of ultrasonic energy due to boundaries between tuned components. Therefore, in this study the mode-degenerating characteristics are achieved by incorporating the helical slits and exponential geometry features in the front mass of the transducer itself. Finite element analysis and vibration experimental analysis show that this strategy prevents coupling of bending modes, increases responsiveness, and reduces energy losses. Most importantly the transducer delivers a very high torsionality.

A new piezoelectric ceramic longitudinal–torsional composite ultrasonic vibrator for wire drawing

“…As is well known, ultrasonic transducer has been developed relatively mature in recent decades, including many vibration mode, such as longitudinal [3], radial [4], torsional [5,6], bending [7], longitudinal-radial (L&R) composite [8], longitudinal-bending (L&B) composite [9,10], longitudinaltorsional (L&T) composite [11], bending-torsional (B&T) composite [12], and so on.…”

Innovative design and analysis of a longitudinal-torsional transducer with the shared node plane applied for ultrasonic assisted milling

“…Significant work has been undertaken by Al-Budairi et al. 12,13 and Yahya Radi Najafabadi 14 on the former. They developed tapered, helically slotted L-T transducers based on the study of numerical analysis and analytical model.…”

Development of Magnetostrictive Resonant Torsional Vibrator

“…That was a piezoelectric which polarized in circumferential direction. Two methods can be seen in researches for generating torsional vibrations: first, conversion of the longitudinal vibration to the torsional vibration [7,8], and the second, using tangentially polarized piezoelectrics [9,10]. However, since the structure design of the first type is complicated, the uses of them are not widespread in industries.…”