Influence of pitch motion on level ice actions

Abstract

The effect of pitch motion on the forces applied to conical structures by ice has been analysed by means of model tests and numerical analyses. The model test setup allowed a direct comparison between a cone in fixed condition and compliant condition in which it was able to rotate only in pitch. A numerical analysis was performed to demonstrate results and conclusions from the model tests.It was determined that the structural response (pitch motion) affected the loading process and the ice forces. The model test demonstrated that compared to the fixed cone, the compliant cone exhibited a reduction in the measured ice forces caused by drifting level ice. The numerical analyses supported the findings of the model test campaign. Several loading conditions were investigated by changing the ice drift velocities. Both the structural response and the loading process of the compliant cone changed under different ice drift velocities due to different dynamic response behaviours. It was concluded that the pitch rotation significantly influenced the ice forces acting on the cone, illustrating the importance of including structural response in the design of Arctic structures when calculating ice actions.