The interaction of two colinear in-plane shear cracks is investigated within the context of couple-stress elasticity. This theory introduces characteristic material length scales that emerge from the underlying microstructure and has proved to be very effective for modeling complex microstructured materials. An exact solution of the boundary value problem is obtained through integral transforms and singular integral equations. The main goal is to explain the size effects that are experimentally observed in fracture of brittle microstructured materials. Two basic configurations are considered: a micro-macrocrack interaction, and a micro-microcrack interaction. Numerical results are presented illustrating the effects of couple-stresses on the stress intensity factor and the energy release rate. It is shown that significant deviations from the predictions of the standard LEFM occur when the geometrical lengths of the problem become comparable to the characteristic material length of the couple-stress theory revealing that in such cases it is inadequate to analyze fracture problems employing only classical elasticity considerations.

中文翻译：

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通过耦合应力弹性建模的微结构材料中剪切裂纹的相互作用

在耦合应力弹性的背景下研究了两个共线的平面内剪切裂纹的相互作用。该理论引入了从底层微观结构中出现的特征材料长度尺度，并已证明对于模拟复杂的微观结构材料非常有效。通过积分变换和奇异积分方程得到边值问题的精确解。主要目标是解释在脆性微结构材料断裂中实验观察到的尺寸效应。考虑两种基本配置：微-宏观裂纹相互作用和微-微裂纹相互作用。数值结果显示了耦合应力对应力强度因子和能量释放率的影响。