Session: 07-04-01 Ships and Structures in Ice

Submission Number: 176233

Ice-Induced Vibrations in Two Channel Markers in the Bay of Bothnia During Winter 2024-2025 

Ice-induced vibrations were measured with accelerometers on two channel markers in the Bay of Bothnia during ice season 2024-2025. The aim is to improve and validate ice load models for conical structures to be applied for offshore wind turbines in freezing sea areas. As channel markers and offshore wind turbines are both slender structures they exhibit similar behavior in ice. Both channel markers have an ice-breaking cone (angle 60 degrees and diameter ~3 m) at the mean water level, and the height of the structure is 12 m above the water. The accelerometers were placed at the top of the structure and at around 6 m height. The measurement campaign resulted in approximately 130 recorded events from the more northern location with yearly heavy ice conditions, and 3 events from the more southern location with varying ice conditions. The measurements show the development of vibrations during the ice failure process as well as the distribution of peak vibration levels and time intervals between ice failure events. Based on these together with measured ice conditions with an upward looking sonar and a numerical model of the channel marker, both the ice failure process and ice loads can be evaluated. The focus of this paper is on the statistical analysis of the measurement data

Presenting Author: Eeva Mikkola VTT

Presenting Author Biography: Dr. Eeva Mikkola is a Doctor of Science (Tech.) in Applied Mechanics, having earned the degree from Aalto University in 2016. Dr. Mikkola currently serves as Research Team Leader for Arctic Infrastructure at VTT Technical Research Centre of Finland. Her academic expertise centers on offshore wind energy in icy regions, full-scale measurements in offshore environments, fatigue of welded structures, and structural integrity. She has also contributed to marine spatial planning research.

Authors:

Eeva Mikkola VTT
Ilkka Perälä VTT
Jaakko Heinonen VTT