New Insights into Current Issues in Nanoindentation from Finite Element/Atomistic Multiscale Modeling

9971429 Brenner将使用有限元/原子多尺度建模模拟金基底的纳米压痕。 模拟，使用的技术适用于研究裂纹扩展的方法，将处理与原子模型的压痕周围的区域。 该区域将嵌入用有限元建模的连续体中。 纳米压痕的动力学，然后可以解决到原子尺度，而不需要一个过多的原子来模拟长程stress.Three系列的模拟将进行，其中每一个都是由一个正在进行的实验合作的结果在北卡罗来纳州州立大学和桑迪亚国家实验室，其中压痕的金基板将进行研究的动机。 在每个模拟中，原子衬底区域将使用公共Sandia-Livermore代码用嵌入原子势建模。 代码来处理连续区的基板将被开发为一组子程序的EAM代码。 在这个项目结束时，这些例程将提供给其他研究人员通过PI的网站。金基板的纳米压痕将使用有限元/原子多尺度建模模拟。 纳米压痕发生在硬度较大的材料，通常以尖头探针的形式，撞击另一个表面时。 基材的响应是相对硬度的量度。 这种纳米压痕模型涉及原子和连续长度尺度的耦合。 该补助金支持理论研究，试图在北卡罗来纳州州立大学和桑迪亚国家实验室进行纳米压痕实验模型。

9971429BrennerNanoindentation of gold substrates will be simulated using finite-element/atomistic multiscale modeling. The simulation, using techniques adapted from methods developed to study crack propagation, will treat the region around the indentation with an atomistic model. This region will be embedded in a continuum modeled with finite elements. The dynamics of nanoindentation may then be resolved to the atomic scale without the need for an excessively large number of atoms to model long-range stresses.Three series of simulations will be carried out, each of which are motivated by the results of an ongoing experimental collaboration at North Carolina State University and Sandia National Laboratory in which the indentation of gold substrates will be studied. In each of the simulations, the atomistic substrate region will be modeled with embedded-atom potentials using the public Sandia-Livermore code. Code to treat the continuum region of the substrate will be developed as a set of subroutines to the EAM code. At the end of this project, these routines will be made available to other researchers through the PI's web site.Nanoindentation of gold substrates will be simulated using finite-element/atomistic multiscale modeling. Nanoindentation occurs when a material of greater hardness, usually in the form of a pointed probe, impinges on the surface of another. The response of the substrate is a measure of the relative hardness. Modeling this nanoindentation involves coupling of atomistic and continuum length-scales. This grant supports theoretical research which attempts to model nanoindentation experiments being conducted at North Carolina State University and Sandia National Laboratory.