Abstract
The measurement of the crack parameters has always been an important task in order to determine the criticality of a crack. Among all the crack parameters studied, crack tip opening displacement is the most important crack parameter for the determination of criticality of crack in ductile material failing under elastic fracture mechanics. Since the displacement near the crack tip is very small, the accurate and direct physical measurement of the in-plane displacement near the crack tip is very difficult. Several theoretical and experimental methods have been developed for the same, and to validate the theoretical predictions, carefully controlled experimental data are required. The present article deals with the use of digital image correlation software 'NCORR' for the experimental determination of in-plane displacement near the crack mouth subsequently determining the crack tip opening displacement and other crack parameters. To check the reliability of the experimental method, the experimental results have been checked with the results of already established finite element analysis. The experimental results have been found to be in good agreement with the numerical results for the same configuration with a very slight deviation (+/- 8%). The deviation in the experimental results with the numerical results may be due to slight deviation in the specifications of the experimental model with respect to the theoretical one. The values of the experimentally determined crack parameters have been used to study the stress distribution near the crack tip.