Multigranular Molecular Dynamics Simulations of Polymer Melts Using Multibody Algorithms

In a multigranular approach for modeling molecular dynamics of polymer melts, different sections of the simulation box are modeled at different levels of detail viz. as particles, flexible bodies or rigid bodies. This approach eliminates high frequency localized motion while maintaining low frequency global conformational motion. This allows for longer integration time steps thus decreasing computational time. In this paper, we discuss our efforts to develop a consortium of dynamics algorithms capable of efficiently generating and solving the equations of motion at all three levels of modeling on a common software platform. A bead spring model of the polymer melt moving under the influence of truncated Lennard-Jones potential under periodic boundary conditions is pursued. Implementation issues and results from a test case consisting of 32 polymer chains of 16 beads each are presented. The paper also discusses the parallel implementation of this problem using MPI.