【摘要】 提出了适用于微区测量的两步数字图像相关法,采用二阶泰勒多项式子区位移模式有效地降低了截断误差;采用B-样条插值函数提高了亚像素重建的精度;采用拟牛顿迭代法提高了计算速度等,使微区内应变测量精度控制在100~150με。在残余应变测量中通过数字标记点相关技术实现了试件的精确复位,提高了其测量精度。文中利用上述方法测量了镀层改性试件跨界面的位移场和应变场,分析了裂纹对镀层的影响以及测出了基材中引起的残余应变;同时对镀层改性界面结合性能作了定量比较。更多还原

【Abstract】 A method of two-steps digital image correlation is well developed with more stable and reliable calculating technology, which consists of a simple searching and an iterative correlation steps. This new method can not only improve the calculating speed and the measuring accuracy, but also simplify the process of experiment. In order to further increase the sensitivity of the technique, the sub-pixel reconstruction is performed in sub-image by utilizing the higher precision calculation of bicubic spline interpolation method, and the accuracy of displacement is enhanced to better than 0.01 pixel, the strain resolution is limited to less than 0.00015 in micro-region. The proposed method is applied to quantify the micro deformation of coating sample. The experimental results show that the present method is a potential boon to investigations for extremely small size scales.更多还原