2005 Volume 48 Issue 4 Pages 178-182
Fracture experiments were conducted using glass tubes by pressurizing internally with high pressure water and the paths of the crack propagations were observed. As the results, it has been clarified that regular wavy cracks often appear in glass tubes and that the shapes of the wavy cracks are approximately similar to one another. Monitoring crack propagations by a high-speed video camera system revealed that a crack snakes sinusoidally only when the crack propagation velocity is sufficiently small comparing with the elastic wave velocity of glass and that the wavy crack never appears when the crack tip velocity is large. Therefore, it can be concluded that the mechanism of the wavy crack propagation is not due to the dynamic effect resulting from the rapid crack propagation. Furthermore, by observing the fracture surface, it was found that the anti-plane shear stress plays an important role in the formation of wavy cracks.