Anisotropy of the effective toughness of layered media
Anisotropy of the effective toughness of layered media
复制标题
DOI：
10.1016/j.jmps.2019.06.021
复制
发表时间：
2019-10-01
影响因子：
5.3
通讯作者：
Bhattacharya, K.
中科院分区：
文献类型：
--
作者：
Brach, S.;Hossain, M. Z.;Bhattacharya, K.
这延续了Hossain等人（2014）和Hsueh等人（2018）开始的层状材料有效韧性研究，重点是各向异性。我们使用相场模型和冲浪边界条件宏观传播裂纹在不同的角度层。我们研究两种理想化的情况下，第一个弹性模量是均匀的，而韧性交替和第二个韧性是均匀的，弹性模量交替。我们发现，在第一种情况下的韧性异质性的有效韧性显示“反常各向同性”，因为它是独立的扩展方向和等于更强硬的材料，除了当裂纹扩展是平行的层。在第二种情况下的弹性不均匀性，我们发现的行为更各向异性和一致的应力波动的增韧效果，并需要裂纹renucleation在顺应刚性界面。在这两种情况下，有效韧性在界面能或Wulff形状的意义上不是凸的，反映了裂纹扩展遵循临界路径的事实。此外，在这两种情况下，裂纹路径不是直线的，并符合最大耗散原理。最后，有效韧性取决于对比度和钉扎，而不是裂纹波动的程度。(C)2019爱思唯尔有限公司版权所有。
This continues the study of the effective toughness of layered materials started in Hossain et al. (2014) and Hsueh et al. (2018), with a focus on anisotropy. We use the phase-field model and the surfing boundary condition to propagate a crack macroscopically at various angles to the layers. We study two idealized situations, the first where the elastic modulus is uniform while the toughness alternates and a second where the toughness is uniform and the elastic modulus alternates. We find that in the first case of toughness heterogeneity the effective toughness displays 'anomalous isotropy' in that it is independent of the propagation direction and equal to that of the tougher material except when the crack propagation is parallel to the layers. In the second case of elastic heterogeneity, we find the behavior more anisotropic and consistent with the toughening effects of stress fluctuation and need for crack renucleation at the compliant-to-stiff interface. In both cases, the effective toughness is not convex in the sense of interfacial energy or Wulff shape reflecting the fact that crack propagation follows a critical path. Further, in both cases the crack path is not straight and consistent with a maximal dissipation principle. Finally, the effective toughness depends on the contrast and pinning, rather than on the extent of crack fluctuation. (C) 2019 Elsevier Ltd. All rights reserved.