Published online by Cambridge University Press: 28 July 2016
The photo-elastic method can be used for either of two main purposes:
a) As a qualitative design tool to obtain indications of possibly unsuspected sources of stress concentration.
(b) As a means of obtaining a complete analysis of a two-dimensional stress problem, i.e., the determination of the separate magnitudes of the principal stresses at any point, as well as the direction of the principal planes relative to some axis of reference.
All that is required for (a) is the stress pattern which becomes visible and can be photographed when a loaded model cut from a sheet of suitable material is placed in a field of circularly polarised light.