Application of the suggested ice strength coefficients in ISO 19906 to intermittent crushing

For offshore wind turbines on monopile or jacket foundations without ice cones, one of the relevant design load cases is that of ice floes or level ice crushing against the structure resulting in ice-induced vibrations. In relation to that design load case, a relevant question is which ice strength coefficient to use in the crushing formula in...

On the feasibility of monopile foundations for offshore wind in the Baltic Sea

For the design of offshore foundations in regions such as the Baltic Sea, it is paramount that ice-structure interaction is appropriately considered. For the monopile, a common foundation for offshore wind turbines, challenges with ice-induced vibrations and high ridge loads may require ice-mitigating measures to be included in the design. A ...

An initial study of interference coloration for quantifying the texture and fabric of ice

The manual application of universal (Rigsby) stage techniques is commonly used to determine the fabric of thin sections of ice viewed with crossed-polarized light. This process can require hours of focus in cold conditions to identify the c-axis of each grain in a thin section. Automated ice texture and fabric methods of several forms exist...

Peak loads during dynamic ice-structure interaction caused by rapid ice strengthening at near-zero relative velocity

A series of ice penetration tests with a rigid structure, with controlled oscillation, and with a single-degree-of-freedom structure were performed to investigate the peak load-velocity dependence for ethanol-doped model ice during a test campaign at the Aalto Ice and Wave Tank. For the rigid structure and controlled-oscillation tests, the...

Hysteresis and dichotomous mechanics in cyclic crushing failure of confined freshwater columnar ice

Cyclic crushing experiments with a haversine velocity waveform were performed on passively confined, freshwater columnar ice specimens for a variety of velocities and frequencies. The aim of the experiments was to study the ice deformation and failure behavior in crushing when loaded at a predefined displacement pattern closely resembling the...

Experimental data from ice basin tests with vertically sided cylindrical structures

Basin tests were performed at the Aalto Ice Tank to gather data on ice-structure action and interaction from ice failing against a vertically sided cylindrical pile. The tests were performed with a real-time hybrid test setup, which combined physical and numerical components to simulate a range of test structures in real-time. The dataset...

Test setup for compressive loading of confined ice thick sections viewed with in-situ cross-polarization imaging

For the topic of predicting ice-induced vibrations of vertically sided offshore structures, the rate-dependent ductile-to-brittle transitional deformation and failure behavior of ice is critical but remains superficially understood. To investigate this knowledge gap, a test setup has been designed which allows for in-situ crossed-polarization...

Classification Of Ice-Induced Vibration Regimes Of Offshore Wind Turbines

Ice-induced vibrations of offshore wind turbines on monopile foundations were investigated experimentally at the Aalto Ice Tank. A real-time hybrid test setup was developed allowing to accurately simulate the motion of a wind turbine in interaction with ice, incorporating the multi-modal aspects of the interaction and the effect of simultaneous...

Experimental study on ice-structure interaction phenomena of vertically sided structures

This study analyses the results from basin tests with a vertically sided cylindrical pile loaded by ice failing in crushing. Tests were performed with a ‘rigid’ structure and with structural models representing a series of single-degree-of-freedom (SDOF) oscillators covering a wide range of mass, frequency, and damping values. The structural...

Ice Basin Tests For Ice-Induced Vibrations Of Offshore Structures In The Shiver Project

With the recent surge in development of offshore wind in the Baltic Sea, Bohai Sea and other ice-prone regions, a need has arisen for new basin tests to qualify the interaction between offshore wind turbines and sea ice. To this end, a series of model tests was performed at the Aalto ice basin as part of the SHIVER project. The tests were aimed...

Simulation and analysis of ice-induced vibrations experienced but Molikpaq during the May 12, 1986 event

Much attention has been given to the dynamic ice-structure interaction of the Molikpaq caisson which resulted in severe, almost catastrophic, structural vibrations during the winter of 1985- 1986 at Amauligak I-65 in the Canadian Beaufort Sea. In this study, specific focus is given to the scientific literature describing the ice-induced...

A study of the transition ice speed from intermittent crushing to frequency lock-in vibrations based on model-scale experiments

For the design of offshore structures in regions with ice-infested waters, the prediction of interaction between ice floe and support structure is essential. If the structure is vertically sided at the ice-structure interface, then ice-induced vibrations can develop. Recently, a dynamic icestructure interaction model has been developed and...

Ice-induced vibrations of model structures with various dynamic properties

For the design of offshore structures in regions with ice-infested waters, the prediction of interaction between floating level ice and the support structure is essential. If the structure is vertically sided at the ice-structure interface and certain ice and structural conditions exist, then the phenomenon known as ice-induced vibrations can...

Experimental validation of a model for prediction of dynamic ice-structure interaction

Vertically sided offshore structures subjected to level ice are designed to withstand the effects of ice-induced vibrations. Such structures are, for example, offshore wind turbines on monopile foundations, multi-legged oil- and gas platforms or lighthouses. For the prediction of dynamic interaction between ice and structures, several...