Application of the Liebmann Formula to the Evaluation of Photoelastic Measurements.

The possibility of using difference expressions of Liebmann type in the evaluation of the results of photoelastic investigations is discussed. The techniques considered include (a) interpolation of the results obtained by experimental point methods, (b) extrapolation of the results - but only in a limited region, of the order of the difference mesh size, and (c) verification and improvement of the accuracy of the measured values of the sum of the normal stresses. Examples of the application of these techniques to plane and axially symmetric problems of elasticity theory are given.