The conventional gradient enhanced plasticity model uses a nonlocal gradient regularization to avoid mesh sensitivity issues present in the continuum-based local plasticity models. These conventional gradient plasticity models are found to manifest spurious spreading of localization zone during the post-peak regime, leading to non-physical structural and fracture response. Therefore, in the present work, a localizing gradient plasticity (LGP) model is proposed to avoid these non-physical responses. The LGP model avoids spurious responses by including the effects of the fracture processes (at micro and macro level) in the model description through the micromorphic framework. The fracture processes are typically found to initiate as a diffused region of plastic deformation (called necking region), which localizes to form cracks upon further loading. An interaction function is adopted in the LGP model to incorporate the localization of the fracture processes. The enhanced capability of the LGP model is demonstrated through one-dimensional and planar problems with tensile, compressive and mixed-mode loading. The numerical results show that the LGP model can arrest the spurious widening of the localization region resulting in a narrow region of high deformation representing failure.

传统的梯度增强塑性模型使用非局部梯度正则化来避免基于连续体的局部塑性模型中存在的网格敏感性问题。发现这些传统的梯度塑性模型在峰后状态期间表现出定位区域的虚假扩展，导致非物理结构和断裂响应。因此，在目前的工作中，提出了一种局部梯度可塑性（LGP）模型来避免这些非物理响应。LGP 模型通过微形态框架将断裂过程（微观和宏观层面）的影响包括在模型描述中，从而避免了虚假响应。断裂过程通常被发现作为塑性变形的扩散区域（称为颈缩区域）开始，在进一步加载时局部形成裂纹。在 LGP 模型中采用了一个相互作用函数来结合断裂过程的定位。LGP 模型的增强能力通过拉伸、压缩和混合模式加载的一维和平面问题得到证明。数值结果表明，LGP 模型可以阻止局部区域的虚假加宽，从而导致出现代表失效的高变形狭窄区域。