Driving forces and boundary conditions in continuum dislocation mechanics
Driving forces and boundary conditions in continuum dislocation mechanics
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连续体位错力学中的驱动力和边界条件
DOI：
10.1098/rspa.2002.1095
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
A. Acharya
中科院分区：
文献类型：
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作者：
A. Acharya
作为本构规范的指南，位错速度和成核率的驱动力是根据 Acharya (2001, J. Mech. Phys. Solids 49, 761–785) 提出的位错力学和晶体塑性场论推导出来的。还导出了位错密度演化边界条件形式的理论封闭条件。闭合条件是通过控制位错密度演化的偏微分方程的线性设置中的唯一性分析生成的。边界条件具有简单的物理意义，即边界的位错流入部分上的向内通量。讨论了位错演化的运动学特征，例如固定螺杆段的弯曲起始和单个螺杆段的交叉滑移起始。针对控制偏微分方程的拟线性系统导出了表示多边形位错环展开的精确解。还讨论了局部（位错水平）施密德和非施密德行为以及（卸载）无应力和稳定微观结构等特征的理论表示。
As a guide to constitutive specification, driving forces for dislocation velocity and nucleation rates are derived for a field theory of dislocation mechanics and crystal plasticity proposed in Acharya (2001, J. Mech. Phys. Solids 49, 761–785). A condition of closure for the theory in the form of a boundary condition for dislocation density evolution is also derived. The closure condition is generated from a uniqueness analysis in the linear setting for partial differential equations controlling the evolution of dislocation density. The boundary condition has a simple physical meaning as an inward flux over the dislocation inflow part of the boundary. Kinematical features of dislocation evolution, such as the initiation of bowing of a pinned screw segment and the initiation of cross–slip of a single screw segment, are discussed. An exact solution representing the expansion of a polygonal dislocation loop is derived for a quasilinear system of governing partial differential equations. The representation within the theory of features such as local (dislocation level) Schmid and non–Schmid behaviour as well as (unloaded) stress–free and steady microstructures are also discussed.