In parallel to double-K fracture model, double-G energy criterion based on the energy release rate is proposed, where two pivotal fracture parameters are introduced: the initial fracture toughness Gini and the unstable fracture toughness Gun , which enable us to…
In parallel to double-K fracture model, double-G energy criterion based on the energy release rate is proposed, where two pivotal fracture parameters are introduced: the initial fracture toughness Gini and the unstable fracture toughness Gun , which enable us to distinguish three stages Ic Ic manifested during crack propagation procedure. Moreover, these two parameters are not independent, the discrepancy between them isGc , the energy assumption devoted by cohesive force distributed throughout Ic the fracture process zone (FPZ). Investigation into the double-G energy parameters together with double-K fracture parameters provides that when an equivalent elastic traction-free crack plus an equivalent elastic fictitious crack zone is considered, these fracture parameters still follow the same conversion principle as stated in linear elastic fracture mechanics (LEFM). Accordingly, the double-G energy fracture criterion can be deemed as a supplement to the double-K fracture model in describing the crack propagation in concrete materials.