PROJECT TITLE :
Methods for Atomistic Simulations of Linear and Nonlinear Damping in Nanomechanical Resonators
Atomistic simulations will be used to compute damping from initial principles and gain unprecedented insights into the mechanisms of dissipation. However, the technique remains in its infancy and several foundational aspects remain unexplored. As a step toward addressing these issues, we gift here a comparative study of 5 totally different strategies for estimating damping below isothermal conditions. Classical molecular dynamics was used to simulate the fundamental longitudinal-mode oscillations of nanowires and nanofilms of silicon and nickel at space temperature (three hundred K) in the canonical ensemble using the Nosé-Hoover thermostat. Within the subresonant regime, damping was quantified using the loss tangent and loss issue during steady-state harmonic vibration. The standard issue was obtained by analyzing the spectrum of thermomechanical noise and conjointly from the Duffing-like nonlinearity in the frequency response beneath harmonic excitation. Still, the nonlinear logarithmic decrement was obtained from the Hilbert rework of freely decaying oscillations. We tend to discuss the factors that has got to be thought-about while choosing simulation parameters, establish criteria for convergence and linearity, and highlight the relative deserves and limitations of each method.
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