The application of digital techniques for data acquisition in 2-D transmission photoelasticity and reflection photoelasticity is well developed and these were discussed in the earlier chapters. The extension of digital techniques for data acquisition to integrated photoelasticity and scattered light photoelasticity have just made a beginning. In integrated photoelasticity, one has to determine three parameters experimentally and these are known as characteristic parameters. In scattered light photoelasticity, the illumination levels are quite low due to light scattering. This necessitates the use of high-resolution CCD cameras. The ultimate aim of integrated photoelasticity or scattered light photoelasticity is to evaluate the stress field interior to the model. The current developments on tensorial tomography are discussed in this chapter.

Recent Developments and Future Trends

This paper regards the determination of the SIF in plate composed of twomaterials with crack starting from free edge and growing in direction perpendicular tothe interface. The RGB photoelastic method was used for the following capabilities: fullfield investigation, rapidity, appreciable precision. The result shows that the influenceof the interface is limited within a little area around interface then a greater part ofcrack path is good fitted by the homogeneous Irwin-Westergard formulation. Thegeneral form of the relation between SIF and a-dimensional crack length presents amaximum value of KI for a/h1 dependent to the geometric h1/h2 ratio. The next goal is tofind an analytical relation that describe correctly the stress field at crack tip in a zonenear the interface.

Crack Growth in Bimaterial Joints with Crack Perpendicular to Interface

The application of digital image processing (DIP) techniques to photoelasticity has greatly simplified data reduction and analysis. The softwares reported so far are hardware dependent and hence not portable. A simple PC based device independent software for collection of photoelastic data from digitised fringe patterns is presented. The software is validated by evaluating the near crack tip stress field parameters for a crack subjected to mode I and mode II loadings.

R. Govindarajan

Papers

Towards a device independent digital image processing software for photoelastic analysis