An efficient three-dimensional adaptive quasicontinuum method using variable-node elements

A new quasicontinuum (QC) implementation using the so-called "variable-node finite elements" is reported in this work. Tetrahedral elements, which have been exclusively utilized for the conventional QC are replaced by hexahedral elements in conjunction with the so-called variable-node elements. This enables an effective adaptive mesh refinement in QC, leading to fast and efficient simulations compared with the conventional QC. To confirm the solution accuracy, comparison is made for a nanoindentation problem with a molecular dynamics simulation as well as a molecular mechanics solution. Further examples of nanoindentation are shown and discussed to demonstrate the effectiveness of the present scheme.