462 research outputs found
Charged elastic rings: deformation and dynamics
We report the counter-intuitive instability of charged elastic rings, and the
persistence of sinusoidal deformations in the lowest-energy configurations by
the combination of high-precision numerical simulations and analytical
perturbation calculation. We also study the dynamical evolution of the charged
ring under random disturbance, and reveal the modulation of the dominant
frequencies by the electrostatic force. The purely mechanical analysis of the
classical ring system presented in this work yields insights into the subtlety
of long-range forces in the organization and dynamics of matter.Comment: 8 pages, 5 figure
Collective dynamics and shattering of disturbed two-dimensional Lennard-Jones crystals
Elucidating collective dynamics in crystalline systems is a common scientific
question in multiple fields. In this work, by combination of high-precision
numerical approach and analytical normal mode analysis, we systematically
investigate the dynamical response of two-dimensional Lennard-Jones crystal as
a purely classical mechanical system under random disturbance of varying
strength, and reveal rich microscopic dynamics. Specifically, we observe highly
symmetric velocity field composed of sharply divided coherent and disordered
regions, and identify the order-disorder dynamical transition of the velocity
field. Under stronger disturbance, we reveal the vacancy-driven shattering of
the crystal. This featured disruption mode is fundamentally different from the
dislocation-unbinding scenario in two-dimensional melting. We also examine the
healing dynamics associated with vacancies of varying size. The results in this
work advance our understanding about the formation of collective dynamics and
crystal disruption, and may have implications in elucidating relevant
non-equilibrium behaviors in a host of crystalline systems.Comment: 7 pages, 4 figure
Propagating stress-pulses and wiggling transition revealed in string dynamics
Understanding string dynamics yields insights into the intricate dynamic
behaviors of various filamentary thin structures in nature and industry
covering multiple length scales. In this work, we investigate the planar
dynamics of a flexible string where one end is free and the other end is
subject to transverse and longitudinal motions. Under transverse harmonic
motion, we reveal the propagating pulse structure in the stress profile over
the string, and analyze its role in bringing the system into a chaotic state.
For a string where one end is under longitudinal uniform acceleration, we
identify the wiggling transition, derive the analytical wiggling solution from
the string equations, and present the phase diagram.Comment: 5 pages, 4 figure
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