Transition between crack patterns in quenched glass plates.

摘要: THE study of fracture is an old topic1, but only recently has understanding begun to emerge crack formation, propagation and morphology (which often fractal) 2–8. When a brittle material such as glass broken under tensile stress9, the cracks have complicated morphology10. Fineberg et al.11 showed that this process may be caused by dynamic instability, whereby speed increases until it approaches sound: at point, complex structures appear. But in quasistatic fracture, where tip much smaller than sound, can also exhibit marked changes12. Here we present studies plates sudden carefully controlled cooling. We observe transition from straight regular, wavy increases. The scaling behaviour appropriately defined relaxation time suggests Hopf bifurcation13, like those seen variety other nonlinear systems. At still higher speeds, oscillatory split into first two then four or more branches.