Priezjev Nikolai V
Department of Mechanical and Materials Engineering, Wright State University, Dayton, Ohio 45435, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Mar;91(3):032412. doi: 10.1103/PhysRevE.91.032412. Epub 2015 Mar 20.
The effect of a local shear transformation on plastic deformation of a three-dimensional amorphous solid is studied using molecular dynamics simulations. We consider a spherical inclusion, which is gradually transformed into an ellipsoid of the same volume and then converted back into the sphere. It is shown that at sufficiently large strain amplitudes, the deformation of the material involves localized plastic events that are identified based on the relative displacement of atoms before and after the shear transformation. We find that the density profiles of cage jumps decay away from the inclusion, which correlates well with the radial dependence of the local deformation of the material. At the same strain amplitude, the plastic deformation becomes more pronounced in the cases of weakly damped dynamics or large time scales of the shear transformation. We show that the density profiles can be characterized by the universal function of the radial distance multiplied by a dimensionless factor that depends on the friction coefficient and the time scale of the shear event.
使用分子动力学模拟研究了局部剪切变换对三维非晶态固体塑性变形的影响。我们考虑一个球形夹杂物，它逐渐转变为相同体积的椭球体，然后再变回球体。结果表明，在足够大的应变幅度下，材料的变形涉及局部塑性事件，这些事件是根据剪切变换前后原子的相对位移来识别的。我们发现笼状跳跃的密度分布从夹杂物处衰减，这与材料局部变形的径向依赖性密切相关。在相同的应变幅度下，在弱阻尼动力学或剪切变换的大时间尺度情况下，塑性变形变得更加明显。我们表明，密度分布可以由径向距离的通用函数乘以一个无量纲因子来表征，该因子取决于摩擦系数和剪切事件的时间尺度。
