A simulation model for cleavage crack propagation in bcc polycrystalline solids
A simulation model for cleavage crack propagation in bcc polycrystalline solids
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DOI：
10.1016/j.actamat.2011.04.010
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发表时间：
2011-06
期刊：
影响因子：
9.4
通讯作者：
S. Aihara;Yoichi Tanaka
中科院分区：
文献类型：
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作者：
S. Aihara;Yoichi Tanaka
提出了体心立方多晶固体解理裂纹扩展模型。该模型基于这样一个准则，即选择位于裂纹尖端前面的颗粒中的三个{1+0+0}解理面中的一个，使得作用在该平面上的法应力最大，如果最大法应力超过解理断裂应力，则解理颗粒。正应力是由混合型局部应力强度因子计算得到的，该应力强度因子由一阶近似计算，其中考虑了裂纹表面的不规则性、裂纹前沿的非直线度和解理面间作用于脊处的裂纹闭合力。将计算得到的断口形貌与低合金钢夏比冲击试验的断口形貌进行了比较。解理面间形成的脊线在裂纹扩展过程和断口形态中起着重要作用。文中还讨论了加工区应力三轴性对断口不规则程度的影响。
A model for cleavage crack propagation in a body-centered cubic polycrystalline solid is proposed. The model is based on a criterion that one of the three {1 0 0} cleavage planes in a grain located in front of a crack tip is selected so that normal stress acting on the plane is maximum and the grain is cleaved if the maximum normal stress exceeds the cleavage fracture stress. The normal stress is calculated from mixed mode local stress intensity factors, which are calculated by first-order approximations, where crack surface irregularity, crack front non-straightness and crack closing force acting at ridges between cleavage facets are considered. The calculated fracture surface morphology was compared closely with that of a Charpy impact-tested specimen of low-alloy steel. Ridges formed between the cleavage facets play an important role in the fracture propagation process and fracture surface morphology. The influence of stress triaxiality in the process zone on the extent of fracture surface irregularity is also discussed.