A steady-state plate tearing model for ship grounding over a cone-shaped rock

Abstract

This paper proposes a theoretical model for ship-bottom plate tearing when the ship runs grounding over a cone-shaped rock. The non-linear finite element code LS_DYNA is used to simulate the grounding scenario, to observe the deformation modes and also to verify the proposed model. A simplified, kinematically admissible model is developed to capture the major energy dissipation patterns, which include friction, stretching, bending, and fracture. Based on the upper bound theorem, the analytical expression of the resistance due to plate tearing deformation in the moving direction is derived. Two sets of verification work have been completed to validate the model. One is the comparison between the analytical results and those from Muscat-Fenech experimental data. The comparison results agree well. The other is the numerical simulation verification. A series of bare plate tearing scenarios is simulated and a systematic parameter sensitivity analysis is made for further verification. On purpose of validating the theoretical method's applicability on plate with stiffeners, a typical double-bottom tanker is chosen as the object, and several scenarios are simulated for ship grounding accident over the cone-shaped rock. The proposed theoretical model is then verified again. The proposed analytical model can be used to assess the crashworthiness of a ship during its structural design phase.