Flow and plasticity via nonequilibrium molecular dynamics
The viscous flow of fluids and the plastic flow of solids, such as metals, are interesting from both the practical and the theoretical points of view. Atomistic molecular dynamics simulations provide a way of visualizing and understanding these flows in a detailed microscopic way. Simulations are necessarily carried out at relatively high rates of strain. For this reason they are ideally suited to the study of nonlinear flow phenomena: normal stresses induced by shear deformation, stress rotation, and the coupling of stress with heat flow, for instance. The simulations require appropriate boundary conditions, forces, and equations of motion. Newtonian mechanics is relatively inefficient for this simulation task. A modification, Nonequilibrium Molecular Dynamics, has been developed to simulate nonequilibrium flows. By now, many high-strain-rate rheological studies of flowing (viscous) fluids and (plastic) solids have been carried out. Here I describe the new methods used in the simulations and some results obtained in this way. A three-body shear-flow exercise is appended to make these ideas more concrete.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6217365
- Report Number(s):
- UCRL-90904; CONF-8405247-3; ON: DE85001011
- Country of Publication:
- United States
- Language:
- English
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