每年出版 6 期
ISSN 打印: 1543-1649
ISSN 在线: 1940-4352
Indexed in
Multiple Time Scale Modeling of Stick-Slip Dynamics of Atomistic Systems
摘要
Temporal evolution of an atomistic system may often be classified as a so-called stick-slip process. Such a process is characterized by the presence of two distinct phasesa slow phase when the system's configuration is evolving at a relatively slow pace and a fast phase, when some sudden dramatic changes occur. In this case, there are two disparate time scales involved: the fine scale associated with the fast phase and the coarse scale associated with the slow phase. When the system's evolution happens in a stick-slip manner, atomistic modeling techniques may be developed to take advantage of this multiscale nature of the system's dynamics. Thus, the slow phase may be effectively modeled using a quasi-static energy-minimization procedure, while the fast phase can be modeled dynamically. Recently, one such method was proposed [Medyanik, S. N., and Liu, W. K., Multiple time-scale method for atomistic simulations. Comp. Mech. 2008.] that explores the idea of a sequential coupling between static and dynamic formulations for an idealized one-dimensional model. In the current work, the idea is further developed and validated by applying the method to an actual atomistic system. This has allowed for estimation of the potential CPU time savings due to the method. In addition, the influence of the loading rate on the qualitative behavior of an atomistic system has been explored and the importance of modeling realistic loading rates has been identified. This further justifies the practical importance of the new method that may help to model more realistic loading velocities and strain rates and thus capture the correct physics. Computational savings for a range of loading velocities are reported, and future prospects of the method's development and applications are outlined.