Stick-slip kinetics in a bistable bar immersed in a heat bath
| Autor: | Chuanpeng Sun, Prashant K. Purohit |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Arrhenius equation
Phase boundary Materials science Bistability Applied Mathematics Mechanical Engineering 02 engineering and technology Mechanics Dissipation Viscous liquid 021001 nanoscience & nanotechnology Condensed Matter Physics Kinetic energy Article symbols.namesake 020303 mechanical engineering & transports 0203 mechanical engineering Mechanics of Materials Modeling and Simulation symbols General Materials Science Boundary value problem 0210 nano-technology Langevin dynamics |
| Zdroj: | Int J Solids Struct |
| ISSN: | 0020-7683 |
| Popis: | Structural transitions in some rod-like biological macromolecules under tension are known to proceed by the propagation through the length of the molecule of an interface separating two phases. A continuum mechanical description of the motion of this interface, or phase boundary, takes the form of a kinetic law which relates the thermodynamic driving force across it with its velocity in the reference configuration. For biological macromolecules immersed in a heat bath, thermally activated kinetics described by the Arrhenius law is often a good choice. Here we show that ‘stick-slip’ kinetics, characteristic of friction, can also arise in an overdamped bistable bar immersed in a heat bath. To mimic a rod-like biomolecule we model the bar as a chain of masses and bistable springs moving in a viscous fluid. We conduct Langevin dynamics calculations on the chain and extract a temperature dependent kinetic relation by observing that the dissipation at a phase boundary can be estimated by performing an energy balance. Using this kinetic relation we solve boundary value problems for a bistable bar immersed in a constant temperature bath and show that the resultant force-extension relation matches very well with the Langevin dynamics results. We estimate the force fluctuations at the pulled end of the bar due to thermal kicks from the bath by using a partition function. We also show rate dependence of hysteresis in cyclic loading of the bar arising from the stick-slip kinetics. Our kinetic relation could be applied to rod-like biomolecules, such as, DNA and coiled-coil proteins which exhibit structural transitions that depend on both temperature and loading rate. |
| Databáze: | OpenAIRE |
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