  The first and second mode stress intensity factors (SIFs) of a contact
problem between a half-plane with an edge crack and an asymmetric tilted wedge
were obtained using experimental method of Digital Image Correlation (DIC). In
this technique, displacement and strain fields can be measured using two
digital images of the same sample at different stages of loading. However,
several images were taken consequently in each stage of this experiment to
avoid the noise effect. A pair of images of each stage was compared to each
other. Then, the correlation coefficients between them were studied using a
computer code. The pairs with the correlation coefficient higher than 0.8 were
selected as the acceptable match for displacement measurements near the crack
tip. Subsequently, the SIFs of specimens were calculated using displacement
fields obtained from DIC method. The effect of wedge tips angle on their SIFs
was also studied. Moreover, the results of DIC method were compared with the
results of photoelasticity method and a close agreement between them was
observed.
