本文阐述了一种利用透明平板模型前后表面反射的两束激光相干涉以获得应力等和线的方法。文中对两束表面反射激光束的相干作用作了数学解释,并给出了实验结果。这种等和线图案与传统方法所得到的等和线有所不同。除了主应力和条纹外,还有许多细栅格线,因此利用富氏光学系统可使应力条纹得到倍增。 This paper presents a method for obtaining the sum of stress lines by using two laser beams coherently reflected by the front and back surfaces of the transparent slab model. In this paper, we give a mathematical explanation of the coherence of the two laser beams reflected by the surface and give the experimental results. This isometric line pattern is different from the equivalent line obtained by the traditional method. In addition to the principal stress and streaks, there are many fine grid lines, so stress streaks can be doubled with Fu’s optics.