A study of forming of thin-walled hemispheres by mandrel-free spinning of commercially pure aluminum tubes
A study of forming of thin-walled hemispheres by mandrel-free spinning of commercially pure aluminum tubes
复制标题
工业纯铝管无芯轴旋压薄壁半球成形研究
DOI：
10.1016/j.jmapro.2020.12.036
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发表时间：
2021
影响因子：
6.2
通讯作者：
Kouyama Jin
中科院分区：
文献类型：
--
作者：
Roy Biplov Kumar;Korkolis Yannis P.;Arai Yoshio;Araki Wakako;Iijima Takafumi;Kouyama Jin
本研究的目的是了解工艺参数在多道次、无芯轴、室温管材旋压中的作用，特别是轴向进给速率在生产半球形件时对形状和厚度变化的作用。这是解决与实验和分析相结合。本研究的材料是热处理的、直径为100 mm的商业纯铝（AA 1070）管。要生成半球，将选择七个线性刀路。在三种不同的轴向进给速度（2、5和7.5mm/rev）下，对两种壁厚（2 mm和3 mm）的管材进行了旋压实验。和相同的径向进给速率（5 mm/道次）。结果发现，降低轴向进给速度产生较小的空间变化，在最终的厚度，同时也使该过程更慢。在每次实验中，管轴向起皱。在不同的旋压道次后中断实验，测量了旋压件的形状和厚度。三种不同的有限元模型，分别使用轴对称，壳和固体元素。将它们与实验进行比较表明，计算效率高的轴对称模型给出了合理的形状和厚度预测。壳单元模型倾向于过度预测旋压过程中的形状和厚度演变，同时慢约250倍。最后，实体单元模型提供了良好的协议与实验的全面，而只有2倍的速度比壳单元之一。因此，推荐在工业实践中使用轴对称模型进行初步工艺设计（即，刀具路径和工艺参数的选择），然后用实体单元模型来细化这些选择。
The purpose of this research is to understand the effect of process parameters in multi-pass, mandrel-free, room-temperature tube-spinning, and in particular the role of axial feed-rate on the shape and thickness change when producing a hemisphere. This is tackled with a combination of experiments and analysis. The material of this study is heat-treated, commercially-pure aluminum (AA1070) tubes of 100 mm diameter. To produce the hemisphere, seven linear passes are selected. The spinning experiments are conducted for two tube thicknesses (2 mm and 3 mm) under three different axial feed-rates (2, 5, and 7.5 mm/rev.) and identical radial feed-rate (5 mm/pass). It is found that decreasing the axial feed-rate generates less spatial variation in the final thickness, while also making the process slower. During every experiment, the tube wrinkles axially. The experiments are interrupted after different spinning passes, and the shape and thickness are measured. Three different finite element models are described, using axisymmetric, shell and solid elements, respectively. Comparing them to the experiments shows that the computationally-efficient axisymmetric model gives reasonable shape and thickness predictions. The shell element model tends to overpredict the shape and thickness evolution during spinning, while being about 250 times slower. Finally, the solid element model provides good agreement with the experiments across the board, while being only 2 times slower than the shell element one. Hence it is recommended for industrial practice to use the axisymmetric model for preliminary process design (i.e., selection of toolpath and process parameters) and then to refine these selections with the solid element model.