2020 Volume 20 Issue 3 Pages 194-200
Image measurement with high spatial and high temporal resolution is applied on the crack bifurcation. Images of in-plane behavior of bifurcation of the running crack in transparent specimen are captured with the frame rate of 0.2 micro second per frame and the spatial resolution of 0.017mm per pixel. As a result, it is revealed that the crack bifurcated into two or three parallel cracks and they propagate with tiny separation before, so called, bifurcation point. Images of 3 dimensional behavior of bifurcation of the running crack are captured by the ultra high speed camera, which is set inclined to the horizontal plane. The frame rate of the image capturing is 0.2 micro second per frame, and the spatial resolution is 0.058 mm per pixel. As a result, it is observed that the initiation of the crack bifurcation is not the through crack but the partial cracks and bifurcated partial cracks grow up into through cracks after bifurcation.
