Abstract
In this work, molecular statics is used to model a nanoindentation test on a two-dimensional hexagonal lattice. To this end, the QuasiContinuum (QC) method with adaptive propagation of the fully resolved domain is used to reduce the computational cost required by the full atomistic model. Three different adaptive mesh refinement criteria are introduced and tested, based on: (i) the Zienkiewicz–Zhu criterion (used for the deformation gradient), (ii) local atoms’ site energy, and (iii) local lattice disregistry. Accuracy and efficiency of individual refinement schemes are compared against the full atomistic model and obtained results are discussed.
Highlights
Nanoindentation is a commonly used testing procedure applied to small volumes of materials for measuring their micromechanical properties
Numerical models are typically used as a tool for better understanding the underlying phenomena, and to obtain detailed information about local mechanisms occurring below the indenter tip, which directly influence measured reaction force. Both the indenter and specimen are typically modelled at the atomistic level using molecular statics or molecular dynamics, entailing high computational costs when realistic configurations and dimensions are used
This paper focuses on the predictive abilities of an adaptive QC methodology in combination with three types of error indicators/estimators for local mesh refinement compared against the full atomistic simulations
Summary
Nanoindentation is a commonly used testing procedure applied to small volumes of materials for measuring their micromechanical properties. Loading force and penetration depth of the indenter are recorded during the loading and unloading stages, providing a basis for the estimation of the unknown mechanical properties. Numerical models are typically used as a tool for better understanding the underlying phenomena, and to obtain detailed information about local mechanisms occurring below the indenter tip (such as dislocation nucleation, propagation, and interaction), which directly influence measured reaction force. To this end, both the indenter and specimen are typically modelled at the atomistic level using molecular statics or molecular dynamics, entailing high computational costs when realistic configurations and dimensions are used. The QuasiContinuum (QC) method (cf. e.g. [1]) is employed to simplify the full atomistic model, to reduce the associated computational costs, and to allow for modelling of realistic situations
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