Full-field separation of principal stresses by combined thermo- and photoelasticity

The combined use of thermoelastic stress analysis and full-field reflection photoelasticity based on the phase-stepping technique has been developed for two-dimensional problems. The first method determines the sum of the principal stresses, the latter evaluates the difference of the principal stresses, Thus the principal stresses were separated at each point in the field of view without reference to neighboring points, An evaluation of this approach has been performed using a tensile plate with a central circular hole. The results show that the analysis carried out combining thermo- and photoelasticity incurred errors no larger than those of each system working independently.