Abstract
The theories of Drucker-Mindlin and Mindlin-Goodman point out that the ratio R plays an important role in 3D photoelasticity. R is a ratio whose numerator is the rate of rotation of the secondary principal axes and whose denominator is the rate of relative phase retardation that would obtain in the absence of rotation. In this paper a set of tranformed equations having explicitly the ratio R is derived from the 3D photoelastic equations, which are Aben's equations and Mindlin-Goodman's equations applied to a monochromatic field. Properties of the resulting equations are clarified by using the Poincare sphere. The equations obtained here are available for 3D photoelasticity.
