Ductile fracture of dual-phase steel sheets under bending
Ductile fracture of dual-phase steel sheets under bending
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DOI：
10.1016/j.ijplas.2019.08.019
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发表时间：
2020-02
影响因子：
9.8
通讯作者：
Y. Liu;D. Fan;S. Bhat;A. Srivastava
中科院分区：
文献类型：
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作者：
Y. Liu;D. Fan;S. Bhat;A. Srivastava
涉及微尺度空隙的成核、生长和聚结的延性断裂限制了各种金属部件和结构的性能、安全性、可靠性和可制造性。这一现象受变形几何形状、加载条件和材料微观结构引起的长度尺度的影响。例如，在单轴拉伸下，双相（DP）高级高强度钢板沿沿着轧制方向（RD）和横向方向（TD）表现出类似的流动响应，其中沿RD的延展性沿着等于或大于TD。而弯曲轴平行于RD方向的板材试件的弯曲度小于弯曲轴平行于TD方向的板材试件的弯曲度。本工作的目的是模拟的长度尺度的相互作用引起的弯曲和微观结构的韧性断裂的DP钢板。为此，基于微观结构的有限元计算的韧性断裂在DP钢板弯曲下进行了。在计算中，DP微观结构中的弯曲试样离散建模。我们的研究结果表明，微观状态的应力/应变，因此，在DP钢板弯曲下的损伤演化是高度不均匀的。讨论了弯曲引起的长度尺度和DP微观结构对裂纹形核和早期裂纹扩展的影响程度。参数的研究，以量化的初始孔隙率，二次空隙成核和能量耗散损伤演化裂纹成核之前的DP钢板的弯曲性能的影响也进行了。
Ductile fracture involving nucleation, growth and coalescence of microscale voids limits the performance, safety, reliability and manufacturability of a variety of metallic components and structures. This phenomenon is affected by length-scales induced by the geometry of deformation, loading conditions and microstructure of the material. For example, under uniaxial tension, dual-phase (DP) advanced high strength steel sheets exhibit similar flow response along rolling (RD) and transverse directions (TD) with ductility along RD being either equal to or greater than TD. However, the bendability of sheet specimens with bend axis parallel to RD is less than the bendability of sheet specimens with bend axis parallel to TD. The objective of this work is to model the interplay of length-scales induced by bending and microstructure on ductile fracture of DP steel sheets. To this end, microstructure-based finite element calculations of ductile fracture in DP steel sheets under bending have been carried out. In the calculations, DP microstructures in a bend specimen are discretely modeled. Our results show that the microscopic state of stress/strain, and hence, damage evolution in DP steel sheets under bending are highly heterogeneous. The extent to which length-scales induced by bending and DP microstructure affects crack nucleation and early stage crack growth is discussed. Parametric studies to quantify the effect of initial porosity, susceptibility to secondary void nucleation and energy dissipated in damage evolution prior to crack nucleation on the bendability of DP steel sheets have also been carried out.