数字散斑相关法在高速变形测量中的应用

在SHTB加载装置上利用数字化的高速摄影和采集系统,并结合数字散斑相关方法,发展了一种光学动态变形测试技术,在霍普金森(Hopkinson)加载装置上实现了具有较高精度和分辨率的位移和变形场的实时光学测量.实验中,利用Imacon-790高速摄影机以105幅/s的速度分别拍摄了两组LY12试件的动态拉伸情况(一维平板拉伸试样和含对称缺口的拉伸试样),然后运用数字散斑相关方法对其不同时刻的图像进行分析和处理,可以得到试样在各个时间点的位移场.最后利用有限元数值模拟技术与实验结果进行了比较,验证了整个系统以及数字散斑相关方法用于高速动态测量中的可行性.

Digital Speckle Correlation Method and Its Application on Impact Deformation Measurement

A real-time and in situ optical measuring system is developed, which can be used to observe the deformation of structures under impacting loading. The system consists of the high-speed camera, digital acquisition, laser light source, synchronization controlling system and analysis software based on the digital correlation theory. The optical system has been adapted to investigate the dynamic deformation fields of normal impact tension sample and plain plate with notches loaded by split Hopkinson tension device. Results obtained in experiments are discussed and compared with finite element simulations and classical Hopkinson bar method. It is proved partly that the measuring system, developed in this paper, is effective and valid.