The application of photo-orthotropic elasticity

Abstract

A brief review of the recent developments in photo-orthotropic elasticity which covers methods of producing transparent, birefringent orthotropic model materials from glass fibres and plastics is presented. A classical form of the stress-optic law applicable in uniaxial-stress fields is given in which the orthotropic characteristics of the model material are treated by considering the material fringe value f_u to be dependent upon fibre orientation. Limitations of the orthotropic model materials are identified and the effects of material non-linearities, fibre debonding and fibre distribution are described. The methods established were used to obtain a solution of the stresses in an orthotropic half-plane loaded with a concentrated force. The experimental results obtained were compared with theoretical results due to Green, and while the agreement was good, errors were considerably larger than those encountered in photo-isotropic elasticity. Finally the methods were applied to the solution of boundary stress on an elliptical hole in a finite-width tension strip.