An improved photo-elastic technique for determining the mixed-mode stress-intensity factors for interfacial cracks in a bi-material

Attempts to employ the photo-elastic technique to determine the complex stress-intensity factors of interfacial cracks in a bimaterial reveal the weakness of the technique. This weakness is due to the large errors arising from the measurement of the coordinates of data points and fringe orders near the crack tip. In this paper, an improved photo-elastic approach is proposed to reduce the effects of the measurement errors. The results obtained by this modified method are compared with both a traditional photoelastic solution and a theoretical solution derived from complex potentials. The comparison shows that the modified solution is in better agreement with the theoretical solution as compared with the traditional solution. (C) 1999 Elsevier Science Ltd. All rights reserved.