Collision simulations between an icebreaker and an iceberg considering ship hydrodynamics

Abstract

This paper examines the motion and structural damage of an icebreaker caused by a collision between an icebreaker and an iceberg based on coupling of potential flow theory with finite element analysis. The hydrodynamic subroutine for Abaqus plug-in HydroQus that was newly developed by present authors was used for the collision simulations. The Korean icebreaker ARAON and spherical shape iceberg were assumed for the collision simulations. The hydrostatic restoring stiffnesses, added masses, radiation damping coefficients, first-order wave excitations obtained through the hydrodynamic frequency response analysis were used for the constants of the Cummins equation of motion. The accuracy of HydroQus was validated from the free-decay simulations where there was a reasonable agreement in the out-of-plane ship motions. Applying each hydro-force one by one, parametric simulations were conducted to analyze the effects of the hydro-forces. Four collision phases were considered for the case subjected to a regular wave load: collision at maximum heave amplitude, maximum heave velocity, maximum pitch amplitude, and maximum pitch velocity. The hydrostatic force and radiation force were not critical components in determining structural damage, while wave loads can significantly increase collision-induced impact force and structural damage.