摘要
微纳米结构在外加荷载下的变形场测量对于描述和预测微纳米结构力学性能、建立相关模型和理论具有重要意义。目前仍然缺少原位实时测量微纳结构变形场的实验方法,这对微纳米结构的力学性能研究形成了一定的制约。本文结合大规模MD(molecular dynamics,分子动力学)模拟和X射线CDI(coherent diffraction imaging,相干衍射成像)模拟,对通过X射线CDI方法准确测量微纳米结构变形场的可行性进行了验证。首先,通过MD模拟给出纳米梁结构在准静态加载和动态加载后的原子结构模型,然后使用X射线CDI模拟基于实验几何和探测器参数给出原子结构模型的二维X射线相干衍射信号。对得到的相干衍射信号进行二维图像重建,提取出位移场,并与从原子构型提取的位移场进行对比,从而实现对该方法准确性的验证。结果表明,通过X射线CDI获得微纳米结构变形场方法的是可行的,且具有较高的精度。该方法为通过变形场进一步提取微纳米结构纳米尺度的表面特性,如表面杨氏模量和残余表面应力提供了可行方案。
Response of micro-/nano-structures under various loading conditions has drawn great attention due to its wide applications.However,there is still a lack of experimental methods for in-situ characterization.This work combines the large scale molecular dynamics(MD)simulations and coherent x-ray diffraction imaging(CDI)simulations,to validate the feasibility for meauring the deformation fields of micro-/nano-structures accurately with the CDI.Atomic configurations for the CDI simulations are obtained from MD simulations.Two dimensional diffraction patterns are calculated based on experimental geometries and detector parameters.Hybrid input and output(HIO)algorithm is used for image reconstruction.Deformation fields derived from MD simulations and CDI reconstructions are compared.This work demonstrates the feasibility of accurate measurement of the deformation field with CDI,and further provides the opportunities to evaluate the parameterized surface effects of micro-/nano-structures under various loading conditions,such as surface modulus and surface stress.
作者
肖雨佳
陈森
钟政烨
XIAO Yujia;CHEN Sen;ZHONG Zhengye(Key Laboratory of Advanced Technologies of Materials,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,Sichuan,China;The Peac Institute of Multiscale Sciences,Chengdu 610207,Sichuan,China)
出处
《实验力学》
CSCD
北大核心
2021年第4期534-542,共9页
Journal of Experimental Mechanics
基金
国家重大科研仪器研制项目(编号11627901)资助。
