A void descriptor function to uniquely characterize pore networks and predict ductile-metal failure properties
A void descriptor function to uniquely characterize pore networks and predict ductile-metal failure properties
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DOI：
10.1007/s10704-020-00463-1
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发表时间：
2020-06
影响因子：
2.5
通讯作者：
J. M. Erickson;Aowabin Rahman;A. Spear
中科院分区：
文献类型：
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作者：
J. M. Erickson;Aowabin Rahman;A. Spear
孔隙率是铸造和增材制造中常见的空隙缺陷，已知会影响金属的机械响应，使得难以或不可能预测响应变化性。我们介绍了一种新的方法，独特的孔隙网络特征使用的空隙描述符函数（VDF），它可以用来预测延性金属的失效特性，即韧性模量，极限强度，伸长率，断裂位置。VDF通过考虑孔隙位置、大小和到自由表面的距离来量化孔隙的相互关系。使用有限元建模框架，120个拉伸试样与统计相似的孔隙网络进行了模拟（虚拟测试）失败。孔隙网络的特征在于提出的VDF，然后将其与断裂的标称位置（定义为对应于导致最终断裂的主要裂纹的断裂起始位置）进行比较。最大VDF的位置准确预测了120个样本中91个（76%）的断裂位置（± 0.2 mm内），并且被证明是比最大横截面积减少的位置和最大孔径位置更可靠的预测断裂位置的指标。此外，最大VDF值被认为是更高的相关性比分数孔隙率，孔径，减少横截面积，和孔的总数的极限拉伸强度，伸长率，和韧性模量。
Porosity, a commonly occurring void defect in casting and additive manufacturing, is known to affect the mechanical response of metals, making it difficult or impossible to predict response variability. We introduce a new method of uniquely characterizing pore networks using a void descriptor function (VDF), which can be used to predict ductile-metal failure properties, namely, toughness modulus, ultimate strength, elongation, and fracture location. The VDF quantifies the inter-relationships of pores by accounting for pore location, size, and distance to free surface. Using a finite-element-modeling framework, 120 tensile specimens with statistically similar pore networks were simulated (virtually tested) to failure. The pore networks were characterized by the proposed VDF, which was then compared to the nominal location of fracture (defined as the fracture-initiation location corresponding to the dominant crack responsible for final rupture). The location of maximum VDF accurately predicted the fracture location (within ± 0.2 mm) for 91 (76%) of the 120 samples and proved to be a more reliable indicator than the location of maximum reduced cross-section area and the location of largest pore diameter for predicting fracture location. Furthermore, the maximum VDF value was found to be more highly correlated than fraction porosity, pore size, reduced-cross section area, and total number of pores to the ultimate tensile strength, elongation, and toughness modulus.