The Mesoscopic Distinct Element Method for Computationally Guided Structural Nanomaterials Design
Traian Dumitrica
Mechanical Engineering, University of Minnesota
ABSTRACT: The Discrete Element Method (DEM) is the macroscopic method introduced by Peter Cundall and Otto Strack about 40 years ago for simulating the mechanics of geological materials. Dumitrica extends DEM to the meso-scale to enable simulations of the mechanics of carbon nanotube (CNT) composites. To illustrate the potential of the method at this small scale, Dumitrica focuses on recent results where mesoscopic-scale distinct element method (mDEM) simulations for the stretching of CNT networks are bringing fundamental understanding into the CNT yarn formation process. The parameters used by mDEM, including the mesoscale friction, are based on full atomistic results. By bridging across the atomistic and mesoscopic length scales, Dumitrica’s model accurately predicts the mechanical response of the network over a large deformation range. By varying the mesoscopic dissipation as well as the network structure, Dumitrica reveals that mesoscale friction and film morphology are key factors for the yarn formation. Dumitrica’s exploratory results anticipate that the bridging-of-the-scales approach pursued here for neat CNTs can be extended to include enhancement in dissipation caused by specific polymeric layers, and to simulate the different deformation regimes from polymer-specific impregnated CNT networks.
