Abstract This paper presents modeling of the tensile and failure behavior of different nodular cast iron microstructures under variable stress triaxialities. The model is based on a Representative Volume Element (RVE) approach, which reproduces periodic stochastic distributions of nodules within a 3-D cell. Three cast iron matrices, from fully ferritic to fully pearlitic, are considered as representing the various nodular cast iron classes in relation to strength and ductility. Ductile damage and shear damage models are used for ferrite and pearlite, respectively. Several values of stress triaxiality are applied within the RVE. It is found that numerical results support experimental findings in relation to the local strain distribution and damage initiation and accumulation, reproducing macroscopic tensile responses with good approximation. As highlighted by experiments, triaxiality is found to have a strong effect on material ductility and void volume fraction growth.

中文翻译：

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应力三轴性对球墨铸铁失效应变影响的微观力学模型

摘要 本文介绍了不同球墨铸铁显微组织在可变应力三轴下的拉伸和破坏行为的建模。该模型基于代表性体积元素 (RVE) 方法，该方法再现 3-D 单元内结节的周期性随机分布。三种铸铁基体，从全铁素体到全珠光体，被认为代表了与强度和延展性相关的各种球墨铸铁等级。延性损伤和剪切损伤模型分别用于铁素体和珠光体。在 RVE 中应用了几个应力三轴度值。发现数值结果支持与局部应变分布和损伤开始和累积相关的实验结果，以良好的近似再现宏观拉伸响应。