基于数字相关法初始值优化的微悬臂梁弯曲变形与应变测量方法

提出了一种基于数字相关法初始值优化的微悬臂梁弯曲变形与应变测量方法.基于放大的微悬臂梁表面的纹理特征,在尺度空间内进行特征点的测量与匹配,在特征点处进行高阶的数字相关法计算以得到变形参数;将特征点处的变形参数进行二维插值运算以得到任意像素点处变形参数的初始值;采用牛顿拉普森迭代方法计算在特定网格点处的变形参数,进而得到网格点处的位移和应变.通过仿真变形图像的计算结果来确定数字相关法的设定参数,对实际的微悬臂梁变形图像进行应变场计算,并与有限元法的计算结果进行比较,以验证所提出方法的有效性.

A Method for Bending and Strain Measurement of Micro-Cantilever Based on Digital Image Correlation with Initialization Optimization

A method for bending and strain analysis of micro-cantilever with initialization optimization by digital image correlation was proposed. Feature points were detected and matched in the scale space based on the image context obtained under microscope. First, the transformation parameters were calculated by digital image correlation with high order in the feature points. Then, the initial transformation parameters of every pixel of the cantilever were obtained by the interpolation in two dimension which could be used as the initial value for the iterative spatial domain cross correlation algorithm (Newton Raphson method). Finally, the refined displacement and strain information at some special grid were calculated. While the algorithm parameters were optimized in the experiment of the simulated bended images, the performance of the proposed method was verified through the strain comparison with the finite element method.