Simplified Ship Collision Model

Abstract

The serious consequence of ship collisions necessitates the development of regulations and requirements for the subdivision and structural design of ships to reduce damage and environmental pollution from collision, and improve safety. The on-going revision of IMO regulations on oil outflow performance and damage stability in grounding and collision is focused on a transition to probabilistic performance-based standards. This thesis addresses one aspect of this problem, a simplified collision model sufficient to predict collision damage, and fast enough to be used in probabilistic analysis requiring thousands of collision simulations. The simplified collision model (SIMCOL) developed and evaluated in this thesis is based on a time domain simultaneous solution of external dynamics and internal deformation mechanics. The external sub-model uses a three-degree of freedom system for ship dynamics. The internal sub-model determines reacting forces from side and bulkhead structures using mechanisms adapted from Rosenblatt and McDermott, and absorbed energy by decks, bottoms and stringers calculated using the Minorsky correlation as modified by Reardon and Sprung. SIMCOL is applied to a series of collision scenarios. Results are compared with MIT's DAMAGE, a Danish Technical University (DTU) model and ALPS/SCOL. SIMCOL provides a fast, consistent and reasonable result for ship collision analysis. An actual collision case is used in an initial attempt to validate the model. This research is sponsored by the Society of Naval Architects and Marine Engineers (SNAME) and the Ship Structure Committee (SSC).