Advancements in the Simulation of 3D Ductile Damage Transition to Fracture with FORGE®

In this work the latest developments on the damage to fracture transition modeling framework of FORGE® are presented. In [8] & [9] the CIPFAR algorithm (Crack Initiation and propagation using the Phase Field and Adaptive Remeshing) was introduced, leading to a shift in the mesh management paradigm to introduce real cracks from damage fields and for ductile forming simulations. In this work we review the generalized framework enabling to: (1) Simulate damage initiation and propagation as a field state variable following any user-specified material law. This state variable is then used within a Phase-Field approach that serves as a proxy variable to identify the crack location within the continuous mechanics framework. (2) Introduce actual crack discontinuities in the finite-elements mesh by intersection of the phase-field’s gradient with the current mesh. Coupled with an automatic mesh adaptation technique this approach creates a robust framework for complex forming scenarios involving fracture. Further improvements are also introduced in this work: (a) The phase-field framework introduced new numerical parameters, such as a characteristic crack length, that can complexity the model adjustment and its industrial use, here we propose an automated approach to reduce the numerical adjustments. (b) As the crack insertion lays on top of the phase-field gradient computation, and the latter on a field recovery strategy, we also present a tensor filtering strategy enabling a better description of the phase-field gradient required for crack intersection. (c) An alternative automatic isotropic remeshing strategy is also introduced.