The stress field around the propagating crack tip under the static loading is visualized. An ultra high speed camera of 1Mfps (Million frames per second) is applied to visualize the stress field around the crack tip by means of conventional photo-elastic imaging technique. A new video trigger system is also developed to detect the initiation of the crack propagation. As a result, it is revealed that the elastic wave, propagating in the specimen, has a significant effect on the crack propagation behavior.
