Photoelastic Separation of Principal Stresses by Oblique Incidence

Rotation of a two-dimensional model about an axis in its plane is suggested as a simple and quite rapid means of obtaining p and q separately. A determination of retardation (fringe order) in an oblique position is all that is required in addition to the usual photoelastic measurements. Experimental and theoretical evidence is presented to show that accurate results can easily be obtained when the principal stress is of significant magnitude. The method can also be applied in three-dimensional studies.