数字图像相关法的板料成形极限研究与应用

Forming limit research and application of digital image correlation method in sheet metal forming process

为了克服现有板料成形极限测定方法的不足,采用XJTUDIC三维数字散斑应变测量系统,实现了一种基于数字图像相关法的板料成形极限测定新方法。首先,将测量系统架构在杯突试验机上,记录从试验过程初始到破裂的一系列图像,实现应变在线、全场测定。然后,通过对破裂前的最后一张图像进行截线,拟合数据,对颈缩区域插值得到极限应变,从而绘制成形极限曲线图。最后,通过对SPCC36型号碳钢材料板料件成形极限的测量,验证了本文方法的可行性和有效性。

In order to overcome the deficiencies in recent forming limit measuring method of sheet metal, a new method based on digital image correlation method was achieved using XJTUDIC three-dimensional digital speckle strain meas- urement system. First, the measurement system was set on the cupping testing machine, the online and audience meas- urement of the strain were realized by recording a series of images from the initial to the rupture of the experimental process. Then, through intercepting lines on the last image before rupture and fitting the data, and the ultimate strain was gained by interpolating the necking region, so the forming limit curves were obtained. The feasibility and effec- tiveness of this method were verified by measuring the forming limit curve of carbon steel SPCC36.