Objectives Collisions between a side structure of ship and a small iceberg are investigated.

Methods a nonlinear finite element model is established, involving the penalty function method and arbitrary Lagrangian-Eulerian (ALE) algorithm. A numerical simulation of the interaction between the double-sided structure of a tanker and a spherical iceberg is conducted. The numerical model considers the structural deformation, iceberg damage and hydrodynamic effects during the collision process. The effects of collision angle on collision velocity, contact force and structural energy absorption are also analyzed.

Results The results show that the numerical model simulates the interaction between the structure on ship side and small iceberg in as much detail as possible. During the collision process, the peak value of the contact force is closely related to the collision angle and iceberg damage. The contact force increases with the collision angle. Compared to other collision angles, fluid has a significant effect on the iceberg's velocity decay in a normal contact case. Among the structural components of the side structure of tanker, the side shell appears to absorb the most energy. Besides, when the small iceberg is broken, the structural energy absorption decreases and the increasing degree is smaller than in unbroken cases due to the energy loss during the breaking process.

Conclusions To ensure the safety of polar ships, the strength of the side structure should be enhanced and a wide collision angle avoided when colliding with small icebergs.