全场数字化测量光弹性等倾角的五步彩色相移法

通过把相移法与光学彩色信息图像处理技术相结合 ,提出了一种确定全场光弹性等倾角的五步彩色相移法。模型置于白光照射下 ,在起偏镜与分析镜不同设置的平面偏振光场中 ,用彩色数码照相机分别采集五幅等色线与等倾线相耦合的条纹图 ,根据相移法基本原理 ,就可以确定在 0～π/2范围内的等倾角。经过对径压缩圆盘的检验 ,实验结果与理论完全相符。该方法改进了单色光相移法的不足 ,对实验应力分析及其在工程结构强度设计中的应用将起积极的促进作用

Whole-field digital determination of isoclinic parameter by five-step color phase shifting technique

Combining color imaging with phase shifting, a technique named five step color phase shifting is presented to determine the whole field isoclinic parameter. Relevant theory is derived and explicit conditions for directly determining the isoclinic parameter in the range of 0～π/2 are given. A color camera recordes five isoclinic images coupled with isochromatics from a plane polariscope with five different settings, respectively. Experiments have been carried out with a circular disk under diametral compression and results agree well with the exact values obtained from the theory. This technique utilizes white light, which avoids undefined isoclinics near the locations where the isochromatics exist and will have active effect on experimental stress analysis and structural strength design.