title: Ultrasonic propagation in finite-length granular chains.
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.
authors.affiliation: School of Engineering, University of Warwick, CV4 7AL, UK.
authors.forename: D A
authors.initials: DA
authors.lastname: Hutchins
authors.affiliation: School of Engineering, University of Warwick, CV4 7AL, UK.
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Engineering, University of Warwick, CV4 7AL, UK.
authors.forename: O
authors.initials: O
authors.lastname: Akanji
authors.affiliation: School of Engineering, University of Warwick, CV4 7AL, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Thomas
authors.affiliation: School of Engineering, University of Warwick, CV4 7AL, UK.
authors.forename: L A J
authors.initials: LA
authors.lastname: Davis
authors.affiliation: School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Freear
authors.affiliation: School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Harput
authors.affiliation: Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
authors.forename: N
authors.initials: N
authors.lastname: Saffari
authors.affiliation: Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
authors.forename: P
authors.initials: P
authors.lastname: Gelat