Digital photoelasticity is a whole field experimental method which gives two parameters viz. principal stress difference (isochromatic) and principal stress direction (isoclinic) in the form of phasemaps.
Whole field quantitative evaluation of these parameters is a challenge. Several algorithms have been developed for determining the parameters accurately.
Photoelasticity by itself will not give individual stress components. Individual stress components can be evaluated in conjunction with either numerical or other experimental techniques. Sophisticated whole field stress separation methodology has been developed for 2D problems. Research is currently on to extend it for 3D problems.
The results from 2D finite element are post processed to plot isoclinic and isochromatic phasemaps. Combining photoelasticity with finite element to obtain individual stress components from 3D problems is currently underway.
Photoelasticity finds applications in various fields.