There is an undetermined problem for analysis of shear stresses by means of photoelastic experiment that uses of the fringe data showing the principal stress difference and the isoclinic data showing the principal stress directions. It is undistinctness of the isoclinic lines. This paper makes propose of a new method of the shear stress measurements, we named “compound fringe method”, for slices from stress freeging specimen without using any data of isoclinic lines.
To analyze the shear stress distribution in slices by the method, it needs only two fringe data, one is the fringe data in the slices and the another is the fringe data (compound fringe data) in the same slice under added known stresses.
We demonstrated the method by both of the experiments and the computer simulations.