A methodology for evaluating mixed-mode (I + II) SIF, combining experimental data acquired by ESPI with Westergaard type solution

In this study a symmetrical double exposure of He-Ne laser in an optical setup with the angle of 45o is used to determine stress intensity factors. Plexy glass specimens are subjected to external loads by a rotational single-axis loading system, and Electronic Speckle Pattern Interferometry (ESPI) approach is then used to determine the in-plane displacement around the crack-tip in inclined edge cracks under mix-mode loading. Processing displacement fringes with suitable filtering methods, stress intensity factors are then calculated using analytical solutions from linear elastic fracture mechanics (LEFM). The obtained results are then compared to those from finite element analysis and the other published results in the literature.