Numerical simulation of continuous damage and fracture in metal-forming processes with 2D mesh adaptive methodology

An h-adaptive remeshing scheme dedicated to the simulation of macroscopic ductile cracks initiation and propagation during metal forming processes, is proposed. Cracks are represented using a procedure based on fully damaged elements deletion. Element size inside the domain and along the crack path, located inside highly localized zones, is driven by error indicators based on geometrical considerations and the derivatives of physical quantities calculated by diffuse approximation. Saw tooth effects along the crack are smoothed with the use of Bezier curves in order to reduce computational inaccuracy. The mesh can be refined and an important issue of this work is mesh coarsening in order to ensure a reasonable computational cost. Multiple domains can be handled. The procedure can be easily integrated in any standard nonlinear explicit finite element code. Specific fields transfer procedures and an automatic adaptation of the time loading sequences are also presented. The efficiency and robustness of the proposed strategy are validated through some examples which show a good agreement with experimentally observed ductile crack paths under large inelastic strains.