Date(s) - 13/04/2016
3:30 pm - 4:30 pm
Title: Would a perfect Newton’s Cradle ever stop?
Speaker: Dr. Thad Harroun
Institute: Brock University
Location: ABB 102
Newton’s Cradles were the quintessential executive toy of the 1980’s, but there is a subtle complexity to the Physics behind their rhythmic motion. For the last couple of years, we’ve been looking at 1D granular chains, which are simplified models of a Newton’s Cradle, and their non-linear behaviour. Potentially, they have many applications, ranging from shock absorption and vibration reduction, to energy localization.
Force impulses to an unloaded granular chain result in a solitary wave (SW) of kinetic energy, analogous to a soliton of the Korteweg-de Vries equation. When SWs collide with a boundary or another SW, secondary solitary waves (SSWs) are produced as grains break contact. A consequence of this process is the transition from a non-ergodic, SW dominant, phase to the stable “quasi-equilibrium” (QEQ) phase, first
thought to be distinct from true thermodynamic equilibrium. We now believe that in the extreme-time limit, energy in fact is
equipartitioned, and taking a recently developed statistical approach, we show how fluctuations of kinetic energy relate to the specific heat and are modified by the degree of the interaction potential.