结合数码显微镜的数字散斑相关方法精度分析及应用

Analysis of Digital Image Correlation Method Coupling with Digital Microscopy and Its Application

结合数字散斑相关方法和一种新型的显微镜数码显微镜,提出了一种测量多晶材料晶粒尺度面内变形的新方法,并通过零变形校准实验、重聚焦实验和平移实验等一系列验证实验分析了该方法的精度和实用性。作为应用实例,对一种镍基合金试件进行了单向拉伸和疲劳实验,得到了晶粒尺度下具有较大应变梯度的应变分布图像。结果表明,该方法能够得到精确的位移测量数据,是一种理想的测量晶粒尺度变形的光测方法。

A new approach for investigation on the in-plane displacement on a grain scale for polycrystalline materials is proposed in this paper based on coupling digital image correlation method and a new type of microscope--digital microscope. The accuracy and practicability of this approach have been analyzed through a series of validation tests, including non-displacement calibration experiments, refocus experiments and rigid translation experiments. As an example of application, uniform tension test and fatigue experiment were carried out for a Ni based alloy specimen, and strain distribution maps on a grain scale with high strain gradient were obtained. Results show that accurate displacement data may be obtained by this approach; so it is a ideal optical measuring method for deformation measurement on a grain scale.