Fracture in mechanism-based strain gradient plasticity
Fracture in mechanism-based strain gradient plasticity
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DOI：
10.1016/s0022-5096(00)00070-3
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发表时间：
2001-05
影响因子：
5.3
通讯作者：
Hanqing Jiang;Yonggang Huang;Z. Zhuang;K. Hwang
中科院分区：
文献类型：
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作者：
Hanqing Jiang;Yonggang Huang;Z. Zhuang;K. Hwang
在一系列引人注目的实验中，Elssner、Korn 和 Ruehle (Scripta Metall. Mater. 31 (1994) 1037) 观察到延性材料中的解理断裂，这是经典塑性理论无法解释的现象。在本文中，我们通过基于机制的应变梯度 (MSG) 塑性理论对断裂进行了研究（Gao 等人，J. Mech. Phys. Solids 47 (1999b) 1239）；黄等人，J. Mech。物理。固体 48 (2000a) 99)。可以确定的是，在远大于位错间距的距离处，使得连续塑性适用，MSG 塑性中的应力水平明显高于裂纹尖端附近的经典塑性中的应力水平。数值结果还表明，MSG塑性场中的裂纹尖端应力奇异性高于HRR场中的裂纹尖端应力奇异性，并且超过或等于平方根奇异性。这项研究提供了一种解释在延性材料中观察到的解理断裂的方法。
In a remarkable series of experiments, Elssner, Korn and Ruehle (Scripta Metall. Mater. 31 (1994) 1037) observed cleavage fracture in ductile materials, a phenomenon that cannot be explained by classical plasticity theories. In this paper we present a study of fracture by the theory of mechanism-based strain gradient (MSG) plasticity (Gao et al., J. Mech. Phys. Solids 47 (1999b) 1239); Huang et al., J. Mech. Phys. Solids 48 (2000a) 99). It is established that, at a distance much larger than the dislocation spacing such that continuum plasticity is applicable, the stress level in MSG plasticity is significantly higher than that in classical plasticity near the crack tip. The numerical results also show that the crack tip stress singularity in MSG plasticity is higher than that in the HRR field, and it exceeds or equals to the square-root singularity. This study provides a means to explain the observed cleavage fracture in ductile material.