Herrmann Christoph, Schneider Daniel, Schoof Ephraim, Schwab Felix, Nestler Britta
Institute of Applied Materials (IAM-CMS), Karlsruhe Institute of Technology (KIT), Kaiserstrasse 12, D-76131 Karlsruhe, Germany.
Institute of Digital Materials Science (IDM), Karlsruhe University of Applied Sciences, Moltkestrasse 30, D-76133 Karlsruhe, Germany.
Materials (Basel). 2021 Aug 30;14(17):4956. doi: 10.3390/ma14174956.
In this work, a small-strain phase-field model is presented, which is able to predict crack propagation in systems with anisotropic brittle and ductile constituents. To model the anisotropic brittle crack propagation, an anisotropic critical energy release rate is used. The brittle constituents behave linear-elastically in a transversely isotropic manner. Ductile crack growth is realised by a special crack degradation function, depending on the accumulated plastic strain, which is calculated by following the J2-plasticity theory. The mechanical jump conditions are applied in solid-solid phase transition regions. The influence of the relevant model parameters on a crack propagating through a planar brittle-ductile interface, and furthermore a crack developing in a domain with a single anisotropic brittle ellipsoid, embedded in a ductile matrix, is investigated. We demonstrate that important properties concerning the mechanical behaviour of grey cast iron, such as the favoured growth of cracks along the graphite lamellae and the tension-compression load asymmetry of the stress-strain response, are covered by the model. The behaviour is analysed on the basis of a simulation domain consisting of three differently oriented elliptical inclusions, embedded in a ductile matrix, which is subjected to tensile and compressive load. The material parameters used correspond to graphite lamellae and pearlite.
在这项工作中，提出了一种小应变相场模型，该模型能够预测具有各向异性脆性和韧性成分的系统中的裂纹扩展。为了模拟各向异性脆性裂纹扩展，使用了各向异性临界能量释放率。脆性成分以横观各向同性的方式表现为线弹性。韧性裂纹扩展通过一个特殊的裂纹退化函数来实现，该函数取决于累积塑性应变，累积塑性应变通过遵循J2塑性理论来计算。机械跳跃条件应用于固-固相变区域。研究了相关模型参数对裂纹穿过平面脆性-韧性界面扩展的影响，以及对在嵌入韧性基体中的具有单个各向异性脆性椭球体的区域中发展的裂纹的影响。我们证明，该模型涵盖了有关灰铸铁力学行为的重要特性，例如裂纹沿石墨片层的优先扩展以及应力-应变响应的拉压载荷不对称性。基于一个由嵌入韧性基体中的三个不同取向的椭圆形夹杂物组成的模拟域来分析其行为，该模拟域承受拉伸和压缩载荷。所使用的材料参数对应于石墨片层和珠光体。
