Plenary and Semi-Plenary Lectures
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| Title: |
| Coupling of length scales for mechanical properties: quantum-mechanics, empirical potentials, and continuum elasticity |
| Lecturer: |
| Noam Bernstein |
| Abstract: |
| Quantum mechanical methods provide the most accurate description of atomic interactions, but they are computationally expensive. Empirical interatomic potentials are a much faster approach to atomistic simulation, but still much less efficient than continuum descriptions of matter. By applying each method only in the region where it is required, we can combine the best features of each. I will discuss some general issues in concurrent coupling of different computational methods, and in particular how they manifest themselves in continuum and atomistic descriptions of solid mechanics. I will then present two ways we have applied this coupling of length scales approach. The first example couples a quantum-mechanical tight-binding method to an interatomic potential simulation. We have used this approach to simulate fracture at zero temperature and at finite temperatures, with the accuracy of a quantum-mechanical description of bonding at the crack tip and a dynamic description of the surrounding strained material. The second example couples a finite-temperature atomistic simulation with a finite-element solution of continuum elasticity. Using this method we have simulated contact and friction between realistic rough surfaces, with an atomistic description of contact and plasticity combined with a realistic description of the stress field deep in the material. |
 Dr. Noam Bernstein received his PhD in Applied Physics from Harvard University with Professor Efthimios Kaxiras, and then worked as a post doctorate NRC fellow at the Naval Research Lab (NRL) working on multiscale simulations. Since 2000, he has been a research physicist at NRL, developing quantum-mechanical and multiscale computational methods and applying them to simulations of mechanical properties, magnetic molecules, and amorphous materials. He is well known for his work in quantum mechanical and atomistic simulation of mechanical behavior. |
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