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.

• Periodical: Applied Mechanics and Materials (Volume 70)
• Pages: 339-344
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.70.339
• Online since: August 2011
• Authors: Hassan Al-Budairi, Patrick Harkness, Margaret Lucas
• Keywords: Longitudinal-Torsional Complex Mode, Mode Degeneration, Transducer, Ultrasonic

References

[1] L.D. Rozenberg: Sources of High-Intensity Ultrasound, Vol. 2, Plenum Press, New York, USA, (1969).

[2] S. Lin: Study on the Longitudinal-torsional Composite Mode Exponential Ultrasonic Horns, Ultrasonics, Vol. 34(7), (1996), pp.757-762.

DOI: 10.1016/0041-624x(96)00062-5

[3] P. Harkness, A. Cardoni and M. Lucas: Ultrasonic Rock Drilling Devices Using Longitudinal-Torsional Compound Vibration, IEEE International Ultrasonics Symposium, Rome, Italy (2009).

DOI: 10.1109/ultsym.2009.5441855

[4] J. Tsujino: Ultrasonic Complex Vibration Systems and Various Applications of High Power Ultrasonics, European and Japanese Symposium on Acoustics, ‏ Sevilla, Spain, (2002).

[5] R. Mahdavinejad: Finite Element Dimensional Design and Modeling of an Ultrasonic Transducer, Iranian Journal of Science & Technology, Transaction B, Engineering, 29(B2), (2005).