Coupling and degenerating modes in longitudinal-torsional step horns

Patrick Harkness; Margaret Lucas; Andrea Cardoni

doi:10.1016/j.ultras.2012.05.002

Coupling and degenerating modes in longitudinal-torsional step horns

Ultrasonics. 2012 Dec;52(8):980-8. doi: 10.1016/j.ultras.2012.05.002. Epub 2012 May 30.

Authors

Patrick Harkness¹, Margaret Lucas, Andrea Cardoni

Affiliation

¹ School of Engineering, University of Glasgow, Glasgow, UK. patrick.harkness@glasgow.ac.uk

PMID: 22770885
DOI: 10.1016/j.ultras.2012.05.002

Abstract

Longitudinal-torsional vibration is used and proposed for a variety of ultrasonic applications including motors, welding, and rock-cutting. To obtain this behavior in an ultrasonic step horn one can either, (i) couple the longitudinal and torsional modes of the horn by incorporating a ring of diagonal slits in the thick base section or, (ii) place helical flutes in the thin stem section to degenerate the longitudinal mode into a modified behavior with a longitudinal-torsional motion. This paper compares the efficacy of these two design approaches using both numerical and experimental techniques.