The presence of cracks in any structure or structural component may result in the total failur of the structure. The stress intensity factor (SIF) provide a single parameter representation for the stress condition at the crack tip.
This paper desoripes a new evaluation method of the isochromatic fringe pattern for the determination of mixed mode stress intensity factor. The method bypasses the error-prone measurements on the isochromatic pattern near to the crack tip and uses data from the near of the crack tip as well as extended stress field. The four parameter method of determining the op-ening mode stress itensity factor (KI), developed by the authors [1) was extended to incorporate the more general case of an arbitrarily oriented crack problem, wher the stress field is governed by two mixed mode factors KIand KII. The method presented here is easy and the use of the full-field data per-mits a significant improvement in the accuracy of determining the mixed mode stress intensity factors. Experimental evidence corroborated the re-sults obtained by the new mehtod.