Nanoindentation is a useful technique to measure material properties at microscopic level. However, the intrinsically multiscale nature makes it challenging for large-scale simulations to be carried out. It is shown that in molecular statics simulations of nanoindentation, the separated dislocation loops (SDLs) are trapped in simulation box which detrimentally affects the plastic behavior in the plastic zone (PZ); and the long-distance propagation of SDLs consumes much computational cost yet with little contribution to the variation of tip force. To tackle the problem, the dislocation loop erasing (DLE) method is proposed in the work to alleviate the influence of artificial boundary conditions on the SDL–PZ interaction and improve simulation efficiency. Simulation results indicate that the force–depth curves obtained from simulations with and without DLE are consistent with each other, while the method with DLE yields more reasonable results of microstructural evolution and shows better efficiency. The new method provides an alternative approach for large-scale molecular simulation of nanoindentation with reliable results and higher efficiency and also sheds lights on improving existing multiscale methods.

中文翻译：

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用位错环擦除法高效可靠地模拟纳米压痕

纳米压痕是在微观水平上测量材料性能的有用技术。然而，本质上的多尺度性质使其难以进行大规模仿真。结果表明，在纳米压痕的分子静态模拟中，分离的位错环（SDL）被困在模拟盒中，这不利地影响了塑性区（PZ）中的塑性行为。SDL的长距离传播消耗大量计算成本，而对尖端力的变化贡献很小。为了解决这个问题，在工作中提出了位错环擦除（DLE）方法，以减轻人为边界条件对SDL-PZ相互作用的影响并提高仿真效率。仿真结果表明，在有和没有DLE的情况下，通过仿真获得的力-深曲线是一致的，而使用DLE的方法会产生更合理的微观结构演化结果，并且效率更高。新方法为纳米压痕的大规模分子模拟提供了一种替代方法，具有可靠的结果和更高的效率，并且为改进现有的多尺度方法提供了启示。