Ductile failure as a constitutive instability in porous plastic solids
Ductile failure as a constitutive instability in porous plastic solids
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DOI：
10.1016/j.jmps.2020.103917
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发表时间：
2020-06
影响因子：
5.3
通讯作者：
S. M. Keralavarma;D. Reddi;A. Benzerga
中科院分区：
文献类型：
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作者：
S. M. Keralavarma;D. Reddi;A. Benzerga
延性破裂的标准是利用莱斯的宏观应变局部化理论以及解释介观尺度不均匀屈服的多孔塑料固体的本构关系推导出来的。在微观尺度上，假设失效是由于沿空隙带的空隙合并而发生的。失效准则的近似无参数封闭式表达式是作为单个标量损伤变量（孔隙率）和宏观应力状态（以应力三轴度和洛德参数为特征）的函数导出的。对于实际应用，开发了一种非耦合方法，其中用无损伤塑性模型和加载路径相关的损伤演化定律补充了失效准则。通过与有限元单元模型研究的比较说明了该方法的预测能力。特别是，对应变硬化的影响进行了一些详细的研究。
A criterion for ductile rupture is derived using Rice’s theory for macroscopic strain localization, and a constitutive relation for porous plastic solids that accounts for inhomogeneous yielding at the mesoscale. At the microscopic scale, it is assumed that failure occurs by void coalescence along a band of voids. An approximate, parameter-free closed form expression for the failure criterion is derived as a function of a single scalar damage variable –the porosity– and the macroscopic stress state, characterized by the stress triaxiality and Lode parameters. For practical applications, an uncoupled approach is developed whereby the failure criterion is supplemented with a damage-free plasticity model and a loading path dependent damage evolution law. The predictive capabilities of the approach are illustrated by comparisons with finite element cell model studies. In particular, the influence of strain hardening is investigated in some detail.