........ 22. 70 C) at elongations from 350 to 525 %. Solid points indicate rupture, the dashed-line gives the ultimate stress. 23. The loci of failure points for a crosslinked poly(styrene-eo-butadiene) rubber obtained as the temperature is increased from Tl to Ts through the glass-rubber transition. 24. Master curve of reduced stress to break vs. reduced time to break for a crosslinked poly(styrene-cobutadiene) rubber. ) Chap. 25. The failure envelope for a poly(styrene-eo-butadiene) rubber.
Sec. 2. Energy Balance in Fracture Basically, some of the energy applied to a specimen may be stored elastically as bonds are strained; energy will also be dissipated if bond breakage or viscous flow (even on a segmental level) occurs. Assuming a glassy solid, in which energy is dissipated by the breakage of bonds and not in viscous processes, Griffith (1921) analyzed the balance between the energy applied and the energy released in bond breakage as a crack propagates, in order to define the critical condition for extension of a flaw to form a catastrophic crack.