A General Damage Initiation and Evolution Model (DIEM) in LS-DYNA

As the automotive industry is reducing the number of physical prototypes in favour of computer simulations during their design processes, a lot of demands is put on the accuracy of the virtual finite element models used for this purpose. In this context the mathematical modelling of fracture is of major importance and has been a field of intense research over the past 50 some years. There are numerous fracture models implemented in LS-DYNA, but as of tradition a fracture model is statically linked to the underlying constitutive model which in practice limits its usage to a single stage of the design process. Recently GISSMO [1,2,3] was introduced in an attempt to remedy this shortcoming by allowing the fracture model to be separated from the constitutive model, thus facilitating results from manufacturing simulations to be transferred to subsequent crash simulations. Behind GISSMO, the Damage Initiation and Evolution Model (DIEM) was developed in the same spirit and with similar capabilities, but this model has to the authors’ knowledge not been used extensively. The intention with this paper is to present this latter fracture model and compare it with GISSMO and, to some extent, with CrachFEM [4] to which it has superficial similarities.