Influence of softening on fracture propagation in large-scale shell structures

In this study, fracture propagation in large shell elements is modelled with the softening law. This law is given in a general form, enabling investigations of different softening behaviours to be conducted. The final fracture is simulated by removing elements. The softening parameters are derived using the energy-based representative volume element (RVE) approach. Tracing crack propagation through the RVE defines the physically justified softening parameters for the current model. The softening model is implemented into ABAQUS using VUMAT subroutines for the shell elements. A large-scale tearing experiment is simulated with the current model and RVE-based softening parameters. In addition, the softening laws from the literature have been used. The fracture propagation is assessed in terms of plastic energy dissipation in the RVE and the whole structure, load–displacement, and crack growth. The RVE-based model is shown to have better performance compared with other models from the literature.