13th International Conference on Fracture June 16–21, 2013, Beijing, China -6- The caustic at the crack tip begins to increase after the arrival of the Rayleigh wave; and the crack starts only through some microseconds. In general, the stress intensity factor decreases after the crack start together with the average speed of the crack. 2,5x10-5 3,0x10-5 3,5x10-5 4,0x10-5 0 2 4 6 crack length (mm) time (s) a 2,5x10-5 3,0x10-5 3,5x10-5 4,0x10-5 0 200 400 600 800 1000 1200 crack speed (m/s) time (s) b Fig. 5. Crack propagation under a localized pulse load on notch edges: a) slit scan of the crack tip trajectory; b) fluctuation of the crack front speed (dashed line - the mean speed). time crack length 10 mm Figure 6. Stress waves in dynamic tests.
RkJQdWJsaXNoZXIy MjM0NDE=