The objectives of this study are to establish numerical approaches to evaluate the structural integrity of a generic Spar hull in collision with a large supply vessel and to reveal its progressive collision damage characteristics.
Dynamic and nonlinear finite element analysis is implemented using ABAQUS/Explicit module  respectively for two collision scenarios. One is a realistic simulation where the impact kinetic energy governed by an initial impact speed and total mass of a ship is gradually depleted during the collision. The other is a simplified analytical method where the impact speed of a ship bow throughout the collision is constant or the total impact energy is unlimited.
With a combination of calibrated material progressive damage models and Mises plasticity, progressive collision damages of the hull structures are accurately captured for structural integrity assessment. The collision energy absorption characteristics, the impact force-deformation curves, the progressive damage modes and the correlation between the impact force, kinetic energy and damages are revealed. Based on numerical investigation, the two analytical scenarios are compared and the implication for the design analysis is elucidated. As a complementary to the ABS code , the alternative collision damage criterion in ABS MODU  applicable to column-stabilized units is justified to be applicable to a Spar subjected to high-energy impact.