Evolution of ultrasonic impulses in chains of spheres using resonant excitation. (10th March 2015)

• Record Type: Journal Article
• Authors: Hutchins, D. A.; Yang, J.; Akanji, O.; Thomas, P. J.; Davies, L. A. J.; Freear, S.; Harput, S.; Saffari, N.; Gelat, P.
• Is Part Of: Europhysics letters. Volume 109:Number 5(2015:Mar.)
• Publication Date: 2015-03-10
• Subjects: 43.35.+d -- 46.40.-f -- 45.50.-j; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/109/54002
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: It is demonstrated that broad-bandwidth ultrasonic signals containing frequency components in excess of 200 kHz can be created in spherical chains using harmonic excitation at 73 kHz. Multiple reflections created a periodic waveform containing both harmonics and sub-harmonics of the original forcing frequency, due to non-linear Hertzian contact. These discrete frequencies represented some of the many allowed non-linear normal modes of vibration of the whole chain. Excitation at a single fixed frequency could thus be used to produce wide-bandwidth impulses for different lengths of spherical chains. Experimental results were in good agreement with theoretical predictions.