Sampling Moir, Method for Accurate Small Deformation Distribution Measurement
Sampling Moir, Method for Accurate Small Deformation Distribution Measurement
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DOI：
10.1007/s11340-009-9239-4
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发表时间：
2010-04-01
影响因子：
2.4
通讯作者：
Morimoto, Y.
中科院分区：
文献类型：
--
作者：
Ri, S.;Fujigaki, M.;Morimoto, Y.
本文提出了一种利用采样云纹法的新型精确变形分布测量技术。报道了钢梁对称三点弯曲的基本原理和实验结果。在该方法中，首先在目标测量区域粘贴已知节距光栅的胶带。将一台普通CCD相机安装在固定点上，以记录变形过程中的图像。通过进行简单的图像处理（即细化和线性插值）对采集到的图像进行分析，以获得多相移云纹图案。然后，可使用相移法计算云纹图案的相位分布。最后，变形分布通过光栅节距乘以变形前后的相位差来计算。对称三点弯曲试验的实验结果表明，钢梁在加载点的位移与精确位移传感器所测结果吻合良好。当使用2毫米光栅节距时，位移测量的平均误差小于4微米，相当于光栅节距精度的1/500。这表明，对于基础设施的结构评估，通过简单易行的程序进行非接触式变形分布测量是可能的，且具有高精度、高速度和低成本的特点。
In this paper, a novel accurate deformation distribution measurement technique by using sampling moir, method is proposed. The basic principle and an experimental result of a steel beam in symmetric three-point bending are reported. In this method, the measurement area of a target is attached with an adhesive tape of a known pitch grating firstly. An ordinary CCD camera is installed on a fixed point to record the image during deformation. The captured image is analyzed by performing easy image processing, i.e., thinning-out and linear interpolation, to obtain the multiple phase-shifted moir, patterns. Then, the phase distribution of the moir, pattern can be calculated using phase-shifting method. Finally, the deformation distribution is calculated by the grating pitch times the phase difference of before deformation and after deformation. The experimental results in symmetric three-point bending test show that the displacement of the steel beam at loading point agree well with those obtained by an accurate displacement sensor. The average error of displacement measurement is less than 4 mu m when 2 mm grating pitch is used, and it corresponds to 1/500 of the grating pitch accuracy. This indicates that noncontact deformation distribution measurement is possible by simple and easy procedure with high accuracy, high speed, and low cost for the structural evaluation of infrastructures.