fig1

Figure 1. The effect of incision diameter on the fracture energy. (A) An elastic body contains an incision with a diameter D. Under an applied force, the incision opens and blunts; (B) The measured fracture energy Γ, depends on the incision diameter D. When D is smaller than a critical length D^*, Γ is a constant, independent of D. When D is larger than the critical length D^*, Γ increases with D.