Strain gradient plasticity theory addresses the plastic strain gradient induced hardening by considering the internal stress and Taylor hardening associated with the geometrically necessary dislocations (GNDs). However, the continuum description of internal stress associated with GNDs is inaccurate due to the coarsening of discrete dislocations. Corrections are thus derived as the difference between the stresses produced by the continuous configuration and the discrete configuration. We further demonstrate the capability of this correction in effectively capturing the internal stress induced strengthening effect associated with GNDs, and elucidate that its role in strengthening is to homogenize the deformation and extend the influence of grain boundaries into the interior of grains within polycrystals. This capability to capture intragranular slip distribution is validated through the simulation of a polycrystalline tensile experiment. This work explains the limitations of classical crystal plasticity theory under high strain gradients and offers a straightforward yet robust slip discreteness correction to crystal plasticity with transparent input from dislocation theory, opening a new perspective for the connections between continuum crystal plasticity theory and dislocation theory.

中文翻译：

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滑移离散校正应变梯度晶体塑性（SDC-SGCP）理论


应变梯度塑性理论通过考虑与几何必要位错 (GND) 相关的内应力和泰勒硬化来解决塑性应变梯度引起的硬化。然而，由于离散位错的粗化，与 GND 相关的内应力的连续描述是不准确的。因此，修正值是由连续配置和离散配置产生的应力之间的差异得出的。我们进一步证明了这种校正能够有效捕获与 GND 相关的内应力引起的强化效应，并阐明其在强化中的作用是均匀化变形并将晶界的影响扩展到多晶内的晶粒内部。这种捕获晶内滑移分布的能力通过多晶拉伸实验的模拟得到了验证。这项工作解释了经典晶体塑性理论在高应变梯度下的局限性，并通过位错理论的透明输入对晶体塑性进行了简单而稳健的滑移离散校正，为连续体晶体塑性理论与位错理论之间的联系开辟了新的视角。