On the nucleation of a Zener crack from a wedge disclination dipole in the presence of a circular inhomogeneity
On the nucleation of a Zener crack from a wedge disclination dipole in the presence of a circular inhomogeneity
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在圆形不均匀性存在的情况下，楔形向错偶极子齐纳裂纹的成核
DOI：
10.1016/j.euromechsol.2009.03.006
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发表时间：
2009-07
影响因子：
4.1
通讯作者：
Chen, Jianqiao
中科院分区：
文献类型：
--
作者：
Wang, Tao;Luo, Jun;Xiao, Zhongmin;Chen, Jianqiao
研究了在圆形非均匀性存在下，由楔形偏斜偶极子形成的i型齐纳裂纹的形核。假设偏斜偶极子和成核齐纳裂纹沿非均匀性的径向分布。本文研究了两种情况，即偶极子的正楔偏斜和负楔偏斜分别靠近非均匀性。为了研究非均匀性与基体之间的弹性失配等因素对齐纳裂纹形核的影响，采用分布位错技术对不同几何参数和材料参数下齐纳裂纹尖端的应力强度因子（SIF）进行了测定。然后用数值方法对所建立的奇异积分方程进行求解。我们的研究结果表明，在第一种情况下，附近的“硬”不均匀性（比基体具有更高的剪切模量）有利于裂纹形核（正偏斜更靠近不均匀性），而在第二种情况下，它延缓了裂纹形核（负偏斜更靠近不均匀性）。在第二种情况下，附近的“软”不均匀性有助于裂纹形核，而在第一种情况下，它对裂纹形核有相反的影响。这种现象可以用物质力的概念来解释。系统地研究了裂纹形核的特征以及偏斜强度、偏斜与偶极子的距离、偏斜偶极子臂长和非均匀性尺寸对裂纹形核的影响。所得结果有助于表征和提高析出相合金和颗粒增强复合材料的强度。
The nucleation of a Mode-I Zener crack from a wedge disclination dipole in the presence of a circular inhomogeneity is investigated. It is assumed that the disclination dipole and the nucleated Zener crack are along the radial direction of the inhomogeneity. Two cases are studied herein, i.e., the positive or negative wedge disclination of the dipole locates nearer to the inhomogeneity respectively. In order to investigate how various factors such as the elastic mismatch between the inhomogeneity and the matrix influence the nucleation of the Zener crack, the Stress Intensity Factor (SIF) at the sharp tip of the Zener crack is determined for different sets of geometric and material parameters with the distributed dislocation technique. The formulated singular integral equations are then solved numerically. Our results indicate that a nearby ‘hard’ inhomogeneity (having a higher shear modulus than the matrix) is beneficial to the crack nucleation for the first case (the positive disclination locates nearer to the inhomogeneity) while it retards the crack nucleation for the second case (the negative disclination locates nearer to the inhomogeneity). A nearby ‘soft’ inhomogeneity is helpful to the crack nucleation for the second case while it has inverse effects on the crack nucleation for the first case. This phenomenon can be explained with the concept of material force. The characteristics of the crack nucleation and the effects of the disclination strength, the distance between the inhomogeneity and the dipole, the disclination dipole arm length and inhomogeneity size on the crack nucleation are also systematically studied. The obtained results are helpful to characterize and enhance the strength of precipitate alloys and particle reinforced composites.
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DOI：
10.4028/www.scientific.net/ssp.87.277
发表时间：
2002-02
期刊：
Solid State Phenomena
影响因子：
--
作者：
M. Wu
通讯作者：
M. Wu
DOI：
10.1016/s0921-5093(97)00196-2
发表时间：
1997-08
影响因子：
6.4
作者：
P. Müllner
通讯作者：
P. Müllner
影响因子：
1.6
作者：
M. Gutkin;I. Ovid’ko
通讯作者：
M. Gutkin;I. Ovid’ko
影响因子：
6.6
作者：
M. Wu
通讯作者：
M. Wu
影响因子：
2.5
作者：
M. Wu;Hongni Zhou
通讯作者：
M. Wu;Hongni Zhou