Strength-based regularization length in phase field fracture

We propose a length-free (LF) implementation of phase field (PF) approach to fracture. The input parameters the LF-PF model are same as those coupled criterion (CC), namely critical energy release rate Gc and material tensile strength ?c. This formulation relies on previously determined correlation between internal length in classical PF fracture models strength. Similar failure loads obtained using either AT1 AT2 versions LF-PF, larger diffused damaged zone being observed AT1. allows retrieving size effect for crack under remote stress infinite medium shows square hole specimen stresses close predictions CC, which both complementary manner. Finally, proposed overcomes problem identifying different lengths configurations.