Numerical investigation and optimization of pulsating and variable blank holder force for identification of formability window for deep drawing of cylindrical cup
Numerical investigation and optimization of pulsating and variable blank holder force for identification of formability window for deep drawing of cylindrical cup
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DOI：
10.1007/s00170-015-7385-7
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发表时间：
2015-06
期刊：
影响因子：
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通讯作者：
S. Kitayama;S. Natsume;K. Yamazaki;Jing Han;Hiroaki Uchida
中科院分区：
文献类型：
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作者：
S. Kitayama;S. Natsume;K. Yamazaki;Jing Han;Hiroaki Uchida
当使用难以拉深的材料时，重要的是要明确表示压边力(BHF)和冲压行程之间关系的成形性窗口。在许多情况下，变压边力(VBHF)是指压边力随冲压行程的变化而变化，对于难以拉深材料的板料成形是非常有用的。另一种方法是使用脉动压边力(PBHF)。因此，PBHF和VBHF的使用对于识别难拉深材料的可成形性窗口是有用的。本文用PBHF和VBHF阐明了难拉深材料的成形性窗口。构造了一个设计优化问题来识别可成形性窗口，在该窗口中，冲头行程最大地受到起皱和撕裂的影响。包括了VBHF和PBHF中的几个参数，并将这些参数作为设计变量。板料冲压成形数值模拟的数值密集度很高，需要采用响应面方法。特别地，采用基于径向基函数(RBF)网络的序贯近似优化方法(SAO)来确定PBHF和VBHF的最优参数。在数值模拟中，采用了基于NUMISHEET 2011(BM1)的圆筒形件拉深成形。通过与基于径向基函数神经网络的SAO相结合的数值模拟，验证了用PBHF和VBHF识别可成形性窗口的方法。数值计算结果表明，该方法可用于确定难拉深材料的成形性窗口。此外，最佳的PBHF可以降低影响刀具寿命的最大冲压载荷。
When a difficult-to-draw material is used, it is important to clarify a formability window representing the relationship between the blank holder force (BHF) and the punch stroke. In many cases, variable blank holder force (VBHF) that the BHF varies through the punch stroke is useful for the successful sheet metal forming to the difficult-to-draw materials. Another approach is to use pulsating blank holder force (PBHF). Therefore, the use of both the PBHF and the VBHF is useful for identifying the formability window of difficult-to-draw materials. In this paper, the formability window of a difficult-to-draw material is clarified with the PBHF and the VBHF. A design optimization problem is constructed to identify the formability window, in which the punch stroke is maximized subject to wrinkling and tearing. Several parameters in the VBHF and PBHF are included, and these are taken as the design variables. Numerical simulation in sheet metal forming is so numerically intensive that response surface approach is used. In particular, a sequential approximate optimization (SAO) using a radial basis function (RBF) network is used to determine the optimal parameter of PBHF and VBHF. In the numerical simulation, deep drawing of a cylindrical cup based on NUMISHEET 2011(BM1) is used. The approach using the PBHF and VBHF for identifying the formability window is examined through the numerical simulation coupled with the SAO using the RBF network. It is found from the numerical result that the proposed approach is useful for clarifying the formability window of a difficult-to-draw material. In addition, the optimal PBHF can reduce the maximum punch load that affects the tool life.