Numerical modelling of ice ridge keel action on subsea structures

The present paper describes a numerical simulation of the keel–structure interaction where the keel geometry, ice thickness and interaction speed present a scaling ratio of 1:20. The rubble is represented by a Drucker–Prager material with cohesive softening and no dilatation. The partial differential equations are solved with the non-linear Eulerian finite element method of Abaqus Explicit V6.8.2. The results are compared to physical experiments conducted in the ice basin of the Hamburg ship model basin (HSVA). Two identical cubic subsea structures were impacted into the unconsolidated keel portion of two ice ridges with different thermal properties. The results indicate that only slight dilatation occurs, and the models are able to estimate the rubble action and deformed shape. A progressive failure of the rubble occurs. The rubble action is influenced more by the friction angle than it is in punch tests, due to higher confinement at the failure surface.

Research Highlights
► Scale model experiments of ice ridge impact on subsea structures are simulated.
► Non-linear Eulerian finite element, rubble described by the Drucker-Prager model.
► The numerical model is able to estimate the rubble action and deformed shape.
► Only slight dilatation and a progressive failure occur in the rubble.
► Effect of rubble friction angle is more significant than it is in punch tests.