The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Dynamics of 1d granular column
Author:	Zuo, Luo
View Online:	njit-etd2014-062 (xvii, 136 pages ~ 7.2 MB pdf)
Department:	Department of Mechanical and Industrial Engineering
Degree:	Doctor of Philosophy
Program:	Mechanical Engineering
Document Type:	Dissertation
Advisory Committee:	Rosato, Anthony D. (Committee chair) Singh, Pushpendra (Committee member) Rao, I. Joga (Committee member) Fischer, Ian Sanford (Committee member) Horntrop, David James (Committee member) Blackmore, Denis L. (Committee member)
Date:	2014-05
Keywords:	Granular material 1d column Particle mechanics Discrete element Dynamical system Tap energy
Availability:	Unrestricted
Abstract:	This dissertation is focused on a discrete element study of the dynamics of a one- dimensional column of inelastic spheres that it subjected to taps by prescribing a half sine wave pulse to supporting floor. Contact interactions obey the Walton-Braun soft-sphere model in which the loading (unloading) path is governing by linear springs of stiffness K1, thereby producing col lisional energy loss through a constant restitution coefficient e. Over a ‘short time scale’, computations are done to examine the floor pulse wave as it propagates through the column contact network. Comparisons of the simulated findings are made with experimental measurements in the literature where possible. Principal emphasis is placed on computing various measures of the evolution of the system that occurs over a long time scale, i.e., the time interval over which the system undergoes a dilation and contraction to a quiescent state after the application of the tap. Here the goal is to chart the column behavior as a function of the amplitude and frequency of the tap, as well as the number of particles in the system and energy dissipation as characterized by. While at the outset, it may appear that this is a simple system, the dynamics in fact are enormously complex as computed Poincaré maps of the mass center trajectories reveal periodic, period doubling and chaotic regimes.