The effect of porosity distribution on ductile failure
The effect of porosity distribution on ductile failure
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DOI：
10.1016/0022-5096(87)90018-4
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发表时间：
1987
影响因子：
5.3
通讯作者：
R. Becker
中科院分区：
文献类型：
--
作者：
R. Becker
数值分析了孔隙率分布不均匀对多孔材料流动局部化和破坏的影响。通过对部分固结铁粉和烧结铁粉的测量，得到了表征材料性能的孔洞密度分布和性能。计算采用了多孔塑料固体的弹-粘塑性本构关系。通过流动势对孔洞体积分数的依赖关系，在模型中考虑了材料的局部破坏。所模拟的区域是一个较大物体的一小部分，受到各种三轴应力条件的影响。在施加周期边界条件的情况下，同时考虑了平面应变和轴对称变形。孔隙率较高的区域之间的相互作用促进了塑性流动局部化成带。局部失效发生在带内的空穴生长和合并。结果表明，破坏准则是基于临界孔洞体积分数的，而临界孔洞体积分数仅弱依赖于应力历史。临界空泡分数是这样。然而，这取决于初始孔洞分布和材料的硬化特性。
Theeffectof a nonuniform distribution of porosity on flow localization and failure in a porous material is analyzed numerically. The void density distribution and properties used to characterize the material behavior were obtained from measurements on partially consolidated and sintered iron powder. The calculations were carried out using an elastic viscoplastic constitutive relation for porous plastic solids. Local material failure is incorporated into the model through the dependence of the flow potential on void volume fraction. The region modelled is a small portion of a larger body, subject to various triaxial stress conditions. Both plane strain and axisymmetric deformations are considered with imposed periodic boundary conditions. Interactions between regions with higher void fractions promote plastic flow localization into a band. Local failure occurs by void growth and coalescence within the band. The results suggest a failure criterion based on a critical void volume fraction that is only weakly dependent on stress history. The critical void fraction does. however, depend on the initial void distribution and material hardening characteristics.