다중스케일 전산역학

Dissipative Particle Dynamics (DPD), a Mesoscale Particle Method for Simulation of Polymers

Tribological Behavior of Grafted Nanoparticle on Polymer-Brushed Walls: A Dissipative Particle Dynamics Study, ACS Appl. Mater. Interfaces 2019, 11, 12, 11988-11998

 

Scale Bridging from Atoms to Continuum

Ongoing Research

When atomistic simulations or atomic resolution experiments are carried out to analyze deformation energetics of atomic lattices near a crack tip, the results of the atomic positions and the total energy of the system have not been systematically converted to field quantities such as stresses or tractions near the crack tip. In this study, we introduce a mathematically consistent way of defining and measuring the cohesive tractions, separations and surface stresses in an atomic decohesion process zone using the atomic displacement data at some distance away from the crack tip. The method is called "nano-scale planar field projection method." This is a generalization of the method developed for isotropic homogeneous solids by Hong and Kim (2003). The formulation introduced here is applicable to interface cracks between anisotropic solids as well as to cracks in homogeneous solids whether they are anisotropic or isotropic. The field projection method is then applied to a crack tip field in gold, simulated atomistically. The atomistic simulation is made with an embedded atom method (EAM) potential for a crystal decohesion along [112] direction in a (111) plane.

Then, the details of energy partition in various modes of nano-scale separation processes are analyzed with the field projection method. The field projection using the interaction J integrals provides the cohesive traction, the interface separation as well as the surface energy and surface-stress gradients caused by gradual variation of surface formation within the cohesive zone. Therefore, the cohesive traction, the surface-energy and the surface stress could be measured as functions of the interface separation.

Figure: Schematic illustration of field projection method, in which the cohesive-zone law can be obtained from MD results for continuum-scale applications.


Link to...

HOME | PEOPLE | RESEARCH | PUBLICATION | FACILITY | BOARD | CONTACT | 한국어