Revisiting MARSTRUCT benchmark study on side-shell collision with a combined localized necking and stress-state dependent ductile fracture model

The MARSTRUCT benchmark study on a small-scale double hull structure penetrated by a hemispherical punch was revisited by employing a combined localized necking and stress-state dependent ductile fracture model. By using the limited information provided to the participants of the benchmark study, the plasticity and fracture model parameters were identified. To model the material behavior beyond moderate plasticity, a combination of the Swift and Voce strain hardening laws was used. The damage indicator framework using the Hosford-, Coulomb fracture model, combined with the Domain of Shell-to-Solid-Equivalence (DSSE) concept, was adopted to predict the initiation and propagation of ductile fracture. Using the adopted approach, the predicted instant and force levels corresponding to the fracture initiation in the upper and lower plates were found to be in good agreement with the test results. The deformation of the structural elements was also accurately captured. The benefits of adopting the damage indicator framework and distinguishing different failure modes were investigated.