Ultrasonic propagation in finite-length granular chains

D A Hutchins; J Yang; O Akanji; P J Thomas; L A J Davis; S Freear; S Harput; N Saffari; P Gelat

doi:10.1016/j.ultras.2015.10.018

Ultrasonic propagation in finite-length granular chains

Ultrasonics. 2016 Jul:69:215-23. doi: 10.1016/j.ultras.2015.10.018. Epub 2015 Nov 2.

Authors

D A Hutchins¹, J Yang¹, O Akanji¹, P J Thomas¹, L A J Davis¹, S Freear², S Harput², N Saffari³, P Gelat³

Affiliations

¹ School of Engineering, University of Warwick, CV4 7AL, UK.
² School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK.
³ Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.

PMID: 26548524
DOI: 10.1016/j.ultras.2015.10.018

Abstract

A narrowband ultrasound source has been used to generate solitary wave impulses in finite-length chains of spheres. Once the input signal is of sufficient amplitude, both harmonics and sub-harmonics of the input frequency can be generated as non-linear normal modes of the system, allowing a train of impulses to be established from a sinusoidal input. The characteristics of the response have been studied as a function of the physical properties of the chain, the input waveform and the level of static pre-compression. The results agree with the predictions of a theoretical model, based on a set of discrete dynamic equations for the spheres for finite-length chains. Impulses are only created for very small pre-compression forces of the order of 0.01N, where strongly non-linear behaviour is expected.

Publication types

Research Support, Non-U.S. Gov't