Quantitative investigations on dislocation based discrete-continuous model of crystal plasticity at submicron scale
Quantitative investigations on dislocation based discrete-continuous model of crystal plasticity at submicron scale
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DOI：
10.1016/j.ijplas.2015.02.002
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发表时间：
2015-06
影响因子：
9.8
通讯作者：
Yinan Cui;Zhanli Liu;Z. Zhuang
中科院分区：
文献类型：
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作者：
Yinan Cui;Zhanli Liu;Z. Zhuang
结合离散位错动力学（DDD）和有限元法（FEM）研究亚微米尺度晶体塑性的多尺度离散-连续模型（DCM）虽已提出多年，但一些关键问题仍未得到很好的解决。首先，提出了一种与滑移面相关的正则化参数的正则化方法，将离散的塑性应变定位到连续的材料点，与以往的研究相比，具有较好的精度。其次，通常认为DCM不能准确地计算作用在自由表面附近位错上的所谓“像力”。本文的研究表明，在采用插值应力计算的混合DCM中，可以准确地计算出像力。在有限变形过程中变形晶体构型的再现是DCM中的另一个关键问题，特别是考虑滑移系统的旋转。为了更好地捕捉局部变形，提出了DDD和FEM之间的变形场传递，以及相应的表面位错和滑移系统旋转处理方法。作为应用，利用改进的DCM成功地研究了薄/厚衬底异质外延薄膜中的位错行为和应力场。
Although the multi-scale discrete-continuous model (DCM) which couples discrete dislocation dynamics (DDD) and finite element method (FEM) to study crystal plasticity at submicron scale has been proposed for many years, some key issues are still not well addressed yet. First, a new regularization method with slip plane dependent regularization parameter is proposed in this paper to localize the discrete plastic strain to continuum material points and shows excellent accuracy compared with previous studies. Second, it is often thought of that DCM cannot accurately calculate the so called ‘image force’ acting on the dislocation near free surface. This study argues that the image force can be calculated accurately in the hybrid DCM in which the interpolated stress is used in the computation. The reproduction of deformed crystal configuration during finite deformation is another critical issue in DCM, especially for considering the rotation of slip system. The deformation field transfer between DDD and FEM, and the corresponding treatment of surface dislocations and slip system rotation are proposed to well capture the localized deformation. As an application, the dislocation behavior and stress field in heteroepitaxial films with thin/thick substrates are successfully investigated by the improved DCM.