Photoelastic method makes use of the gray information in images and then carries out unwrapping on the images to determine the whole field isochromatic fringe orders, so that the stress distribution can be worked out. In this paper, the Patterson and Wang ' s six-step phase shifting method and computer digital image processing technology were applied to the traditional photoelastic method, and the PMMA transparent materials model samples with accurate theoretical solution were tested. Through the implementation of one just shoot and one inclined shoot, combined with image processing technology, transparent material stress distribution was determined. Then the test results and the theoretical solution were compared. The relative error was 7. 9%. Several factors have been analyzed at length. Above all, the feasibility of using this method to study PMMA stress distribution was inferred at the end of this paper.%光弹法测量应力是通过对图像中携带的灰度信息计算出应力条纹的相位信息,然后再对图像去包裹确定全场等差线条纹级次,从而确定应力分量,实现对材料应力分布的考察. 本研究将Patterson和Wang的六步相移法基本原理与计算机数字图像处理技术应用于传统光弹性方法中,选择具有精确理论解的有机玻璃透明材料模型试样进行试验;通过对有机玻璃透明材料实施一次正射加一次斜射的方法,配合图像处理技术,确定了有机玻璃透明材料应力分布,并将试验结果与模型的理论解进行了对比,相对误差为7. 9%;详细分析了引起误差的因素. 本研究结论确定了该方法应用于有机玻璃透明材料应力分布考察中的可行性.
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