factor

Appllcstlon ol carl~er methods of analysis of pho toc i s r t i ~ infoinration in a slnglc cdpe notch spccimcn subjcctto!eni~le!oading to lietermme Mode I strcss intchsity factor brought into i x u s the constraints and the limitstions of the earlier methods. In this investigation. a new approach called the constant B method has been put forth The rcmltr obtained by this method are compared along with the values dcterminrd by using the earlier approaches against the theoretical values ofthe boundary collocation method. The method is quiterel~ahleand theresults are in fair agreement with the houndary collocation results. Key wards: Strcaa intewity factor, crack, fracture mechanics, photoelastmty. Among the experimental techniques to determine the stress intensity factor the well-known are the method of caustics due to Theocaris ' and the photoelastic method. The photoelastic method has been very widely used starting from Irwin3 who used the fringes obtained by Wella and post '. The information gathered from the photoelastic fringes has been analysed by Irwin', Schroedl and Smith4, Bradley and ~obayashi ' , Prabhu " and Rakesh7 for the determination of the Mode I stress intensity factor. Irwin and ~ a k e s h ' , ~ used a single fringe loop. Schroedl and Smith, Bradley and Kobayashi and Prabhu4- ' used two loops. Irwin3 used the coordinates r,. 0, corresponding to the apogee point of any loop (fig. I), wherea