Abstract:Gradient-enhanced ductile damage is implemented in the finite element method by means of an additional field variable, representing non-local damage which is linked to the local damage variable. At material point level the isotropic damage formulation uses exponential damage functions to circumvent further constraints on the value set of the local damage variable. The ductility of the model is achieved by a coupling of damage to finite strain plasticity. In a multisurface approach the onset of damage and plast… Show more
“…Resulting from the plasticity-damage coupling most of the deformation localises inside the (softer) damage zone, which is governed by the internal length scale and typically of small size. Therefore, the localised deformations inside this small zone result in large deformations that combined with the plastic incompressibility cause locking phenomena [15], even when applying small strains. To avoid locking, we used, as already mentioned, standard fully-integrated quadratic hexahedral elements being accurate but expensive.…”
In recent years, clinching has gathered popularity to join sheets of different materials in industrial applications. The manufacturing process has some advantages, as reduced joining time, reduced costs, and the joints show good fatigue properties. To ensure the joint strength, reliable simulations of the material behaviour accounting for process-induced damage are expected to be beneficial to obtain credible values for the ultimate joint strength and its fatigue limit. A finite plasticity gradient-damage material model is outlined to describe the plastic and damage evolutions during the forming of sheet metals, later applied to clinching. The utilised gradient-enhancement cures the damage-induced localisation by introducing a global damage variable as an additional finite element field. Both, plasticity and damage are strongly coupled, but can, due to a dual-surface approach, evolve independently. The ability of the material model to predict damage in strongly deformed sheets, its flexibility and its regularization properties are illustrated by numerical examples.
“…Resulting from the plasticity-damage coupling most of the deformation localises inside the (softer) damage zone, which is governed by the internal length scale and typically of small size. Therefore, the localised deformations inside this small zone result in large deformations that combined with the plastic incompressibility cause locking phenomena [15], even when applying small strains. To avoid locking, we used, as already mentioned, standard fully-integrated quadratic hexahedral elements being accurate but expensive.…”
In recent years, clinching has gathered popularity to join sheets of different materials in industrial applications. The manufacturing process has some advantages, as reduced joining time, reduced costs, and the joints show good fatigue properties. To ensure the joint strength, reliable simulations of the material behaviour accounting for process-induced damage are expected to be beneficial to obtain credible values for the ultimate joint strength and its fatigue limit. A finite plasticity gradient-damage material model is outlined to describe the plastic and damage evolutions during the forming of sheet metals, later applied to clinching. The utilised gradient-enhancement cures the damage-induced localisation by introducing a global damage variable as an additional finite element field. Both, plasticity and damage are strongly coupled, but can, due to a dual-surface approach, evolve independently. The ability of the material model to predict damage in strongly deformed sheets, its flexibility and its regularization properties are illustrated by numerical examples.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.