Fig. 7: Fracture model.
a Schematic illustration of the three main mechanisms contributing to the fracture energy: intrinsic fracture energy Γ0 due to chain scission near the crack interface, bulk dissipation Γbulk due to interchain friction and reptation, and near-crack dissipation Γtip due to distributed damage where Lc is the characteristic length of the process zone. b Schematic illustration showing the effect of non-affinity on the process zone. When networks are affine, the process zone remains close to the network meshsize ξ and the Lake-Thomas model of fracture remains the relevant picture. Chain scission (shown as yellow stars) remains localized. As networks become more non-affine, the damage becomes delocalized leading to an increase in the process zone. The Irwin-Orowan model of fracture is necessary in order to account for the additional near-crack dissipation Γtip.
