Validation of Määttänen-Blenkarn ice model for ice-structure interaction against ice tank tests

This paper describes a validation procedure of the Mä ättänen-Blenkarn ice model for ice-structure interaction against scaled ice tank tests. The tests were performed at the Hamburg Ship Model Basin (HSVA) where a simplified scaled model of the Norströmsgrund lighthouse was built. Several ice-structure interaction tests were performed with various ice thicknesses and velocities. The results of those experiments were compared against results of the numerical simulations performed at Fraunhofer IWES. A numerical model, based on the HSVA structure, was implemented in OneWind simulation tool for offshore wind turbines. The complex geometry of the physical structure was simplified to a single degree of freedom numerical model represented by a rigid beam, a spring and a damper. Its implementation was validated with a set of tests. The static behavior of the numerical structure was validated by a pullout test, whereas dynamic response was checked in terms of eigenfrequencies and a free decay test. These results fit very well to those obtained at HSVA with the physical structure. The original Mä ättänen -Blenkarn ice model could not be directly utilized for validation against the scaled ice tank tests as the relationship between stress and stress rate in the ice model was derived from the full-scale measurements. A new relationship between stress and stress rate for scaled ice was setup. After the tuning of the ice model a good match of simulated displacements, velocities and forces was achieved.