A two characteristic length nonlocal GTN model: Application to cup–cone and slant fracture

Ductile failure prediction is essential to avoid loss of structural integrity or control crack propagation during forming processes. One the main difficulties complex paths. This study proposes a nonlocal extension local Gurson–Tvergaard–Needleman (GTN) ductile damage model at finite strains able capture cup–cone slant fracture. The proposed based on an implicit gradient formulation which enables solve problem spurious strain and localization. integrates two different material characteristic lengths, are used separately regularize by void growth nucleation. After parameter fitting using data for line pipe steel, conditions obtain converged solutions studied, can be select mesh size in localization band. With appropriate design, it was possible effect lengths formation fracture It observed that, given specimen size, larger favor flat advance. Similarly, effects predicted with small specimens being more prone paves way direct determination homothetic so as