改进的六步相移法确定等倾角与等差线相位

光弹性应力分析是一种重要的实验方法,确定等倾线参数和等差线参数是光弹法的关键。常用的六步相移法可以自动确定等倾线和等差线参数,但在求解等倾角时,由于不能避免等倾线相位图中耦合等差线的影响,会造成误差。针对这个问题,本文提出优化方案--多次载荷-六步相移法,实现在等倾线相位图求解中消除等差线的影响。通过处理对称受压圆盘在不同载荷、不同光场下得到的光弹图像,实现光弹性等倾线和等差线的自动判读,验证了所提方法的可行性。

On the Determination of Isoclinic Angle and Isochromatic Line by a Improved Six-step Phase Shifting Method

Photoelastic stress analysis is an important experimental method. The key of this method is to determine isoclinic line parameters and isochromatic line parameters. Commonly used six-step phase shifting method can automatically determine the isoclinic and isochromatic parameters. However in solving the isoclinic angle, this method will cause errors due to unavoidable effect of isochromatic line coupling with isoclinic lines in phase diagram. An optimized program-multiple loads-six-step phase shifting method was proposed to eliminate the effect from isochromatic line when solving the isoclinic line. In this paper, the multiple loads-six-step phase shifting method is used to achieve the automatic interpretation of the isoclinic lines and isochromatic lines through processing photoelastic images obtained under different load and in different light field. Finally, an example is presented to illustrate the merits of proposed method.