Abstract This work concerns the numerical modelling of the deformation process of porous sintered metals, considering the shape of pores on the mesoscopic scale based on microtomography. Sintered 316L steel with various porosity values was used. Limited microtomography device accuracy for porous metals studies results in a lack of fissure mapping and pores with smaller dimensions than the pixel size of the tomographic image. For this reason, two methods were used in this work to compensate for the influence of not mapping the geometric details of porous mesostructures onto the results of numerical calculations. Based on the microtomographic cross-sections obtained, three-dimensional geometric models mapping the shape of the porous structure of the studied materials were created. The models were used for numerical calculations of sintered steel compression behaviour using the finite element method. The modelling also considers self-contact of the porous structure and the effect of closing the pores during compression. As a result, macroscopic stress-strain curves for the studied porous structures and distributions of stress and strain in the deformed material were obtained. Based on the analysis of the numerical calculation results, the deformation process for porous sinters in the range of large plastic strain was described and the influence of porous structure deformation on the mesoscopic scale on the material behaviour in the macroscale was determined. The work also compares the results of tests obtained by three calculation models and points out the advantages and disadvantages of their application to numerical modelling of the deformation process of porous metals.

中文翻译：

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使用计算机显微断层扫描对烧结多孔金属在压缩下的大变形行为进行孔隙尺度数值模拟

摘要 这项工作涉及多孔烧结金属变形过程的数值模拟，在基于显微断层扫描的细观尺度上考虑孔的形状。使用了具有各种孔隙率值的烧结 316L 钢。多孔金属研究的显微断层扫描设备精度有限，导致缺乏裂缝映射和尺寸小于断层扫描图像像素大小的孔隙。为此，在这项工作中使用了两种方法来补偿未将多孔细观结构的几何细节映射到数值计算结果上的影响。基于获得的显微断层扫描横截面，创建了映射所研究材料多孔结构形状的三维几何模型。这些模型用于使用有限元方法对烧结钢压缩行为进行数值计算。该建模还考虑了多孔结构的自接触和压缩过程中关闭孔隙的影响。结果，获得了所研究的多孔结构的宏观应力-应变曲线以及变形材料中的应力和应变分布。在对数值计算结果进行分析的基础上，描述了多孔烧结体在大塑性应变范围内的变形过程，并确定了多孔结构变形在细观尺度上对宏观材料行为的影响。