Development of a dynamic failure prediction tool for marine composite structures

Composite ship structures are subjected to both the low and high velocity impact during their service life. The dynamic impact can generate fiber, matrix and/or delamination damage inside a woven fabric composite laminate, which may significantly reduce its stiffness and strength. Both the structural mechanics and fracture mechanics based models cannot fully capture the impact damage evolution due to coexistence of continuum and discrete damage. The stress and strain at the element level cannot be directly used to predict the constituent damage and the resulting mechanism driven stiffness degradation. In this paper, a hybrid discrete and continuum damage model is developed and numerically implemented within the LS-DYNA environment via a user-defined material model. The continuum damage progression and its associated stiffness degradation are predicted based on the constituent stress/strain and their associated failure criteria while the delamination damage is numerically captured via a cohesive interface model.