Analysis of Earring in Circular-Shell Deep-Drawing Test
Analysis of Earring in Circular-Shell Deep-Drawing Test
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耳环圆壳拉深试验分析
DOI：
10.1299/kikaia.79.595
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Yoshikazu Kobayashi
中科院分区：
文献类型：
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作者：
T. Ohwue;Kazuki Sato;Yoshikazu Kobayashi
为了研究低碳铝镇静钢和纯钛板在拉深成形过程中是否会出现“耳孔”现象，进行了圆壳拉深试验和有限元模拟。提出了一种能准确估计360°全圆壁高耳环花纹的模拟方法，其中R值应在均匀延伸范围内测量，特别是对于纯钛的情况。众所周知，耳环值与平均值ΔR/R成正比的观点并不总是适用于整个板材。尽管纯钛的平均ΔR/R值几乎为零，但它显示出大的耳环。这被认为源于纯钛R值的特征平面各向异性，即大ΔTLave（ave /R R R）（00 90−）和非常小的ΔR。此外，值得注意的是，尽管纯钛显示出在90°方向上最大的直平面各向异性，但在45°方向上的耳环是实验观察到的，并通过模拟再现。纯钛和低碳铝镇静钢的屈服点最佳m值分别为8和2，使实验结果具有较好的再现性。两种金属之间最佳m值的差异可能与滑移系数量的差异有关;即纯钛的活性滑移系数量非常有限。
A circular-shell deep-drawing test and an FEM simulation utilizing LS-DYNA with Barlat-Lian anisotropic yield locus (1989) were conducted in order to investigate the occurrence of earring for low-carbon aluminum-killed steel sheet and pure titanium sheet. The simulation method was developed that can accurately estimate the earring pattern of whole 360°circular wall height, where R -value is supposed to be measured within the range of uniform elongation, in particular for the case of pure titanium. The well known opinion that the earring value is proportional to ave ΔR/R does not always hold for the whole sheet materials. Despite the fact that the value of ave ΔR/R of pure titanium is nearly zero, it exhibits large earring. This is considered to stem from the characteristic planer anisotropy of R-value of pure titanium, namely largeΔTLave ( ave /R R R ) ( 00 90− ) together with very small ΔR . Furthermore, it is interesting to note that the earring in 45°direction was observed experimentally and was reproduced by simulation, despite the fact that pure titanium shows the straight planer anisotropy with the maximum in 90°direction. The optimum m-values in yield locus for pure titanium and low-carbon aluminum-killed steel, which led to the fairly good reproduction of experimental results, is 8 and 2, respectively. This difference in optimum m-value between the two metals is presumably related to the difference in the number of slip system; namely the number of active slip system is very limited for pure titanium.