This paper investigates the influence of surface roughness on multiple necking formation in additive manufactured porous ductile plates subjected to dynamic plane strain stretching. For this purpose, we have developed a computational model in ABAQUS/Explicit which includes surface texture and discrete voids measured from 3D-printed metallic specimens using optical profilometry and X-ray tomography analysis, respectively. The mechanical behavior of the material is described using an elastic–plastic constitutive model, with yielding defined by the isotropic von Mises criterion, an associated flow rule, and a power-law function for the yield stress evolution which depends on plastic strain, plastic strain rate, and temperature. The finite element calculations have been conducted across a broad range of strain rates, from 5000s−1 to 50000s−1, to explore the interactions among inertia, surface roughness, and porosity in determining the necking pattern that emerges in the plates at large strains. The finite element results show that surface roughness induces perturbations in the deformation field of the specimen, which lead to early necking localization, while the location and number of necks formed are primarily controlled by the porous microstructure and the loading rate. The results for the neck spacing have shown quantitative agreement with the analytical stability analysis predictions and the unit-cell finite element calculations reported by Rodríguez-Martínez et al. [1]. Moreover, integrating discrete voids into simulations that already account for surface roughness results in a minor reduction in necking strain: surface roughness and porosity demonstrate similar quantitative impacts on necking ductility, which is primarily influenced by inertia effects at the highest strain rates studied. To the best of the authors’ knowledge, this paper presents the first calculations that explore dynamic plastic localization in additive manufactured metals, incorporating actual surface roughness and explicit void representation derived from experimental measurements. This work marks progress in the analysis of 3D-printed structures under impact loading, aiming to understand and predict the mechanics influencing their energy absorption capacity at high strain rates.

中文翻译：

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表面粗糙度对承受动态平面应变拉伸作用的增材制造多孔金属板中颈缩不稳定性的影响


本文研究了表面粗糙度对受动态平面应变拉伸作用的增材制造多孔延性板中多颈形成的影响。为此，我们在 ABAQUS/Explicit 中开发了一个计算模型，其中包括分别使用光学轮廓测量法和 X 射线断层扫描分析从 3D 打印金属样品中测量的表面纹理和离散空隙。材料的机械行为使用弹塑性本构模型进行描述，屈服由各向同性 von Mises 准则、相关的流动规则和屈服应力演变的幂律函数定义，该函数取决于塑性应变、塑性应变率和温度。有限元计算是在从 5000s-1 到 50000s-1 的广泛应变速率范围内进行的，以探索惯性、表面粗糙度和孔隙率之间的相互作用，以确定在大应变下板中出现的颈缩模式。有限元结果表明，表面粗糙度在试件的变形场中引起扰动，导致早期颈缩定位，而形成颈的位置和数量主要受多孔微观结构和加载速率控制。颈部间距的结果与 Rodríguez-Martínez 等人 [1] 报告的分析稳定性分析预测和晶胞有限元计算在定量上一致。 此外，将离散空隙集成到已经考虑表面粗糙度的仿真中，可以略微减少颈缩应变：表面粗糙度和孔隙率对颈缩延性表现出类似的定量影响，这主要受所研究的最高应变率下的惯性效应的影响。据作者所知，本文提出了探索增材制造金属中动态塑料定位的首次计算，结合了实际表面粗糙度和从实验测量得出的显式空隙表示。这项工作标志着冲击载荷下 3D 打印结构分析的进展，旨在了解和预测在高应变率下影响其能量吸收能力的力学。