Author(s): Grant Peel; Ersegun Deniz Gedikli
Linked Author(s):
Keywords: Sea Ice; Ice-Structure Interaction
Abstract: When subjected to ice-induced vibrations, the dynamics of offshore structures in the Arctic and Sub-Arctic areas are known to exhibit complex non-linear behavior. Parameters such as ice drift velocity, ice drift direction, ice thickness, ice and/or air temperature, for example, change over time throughout the operation and may cause the structure to oscillate with large amplitude motions. The resulting motions may be regular or irregular depending on the nonlinear nature of the force distribution on the structure, and may cause fatigue-related damage to the structure if disregarded in design or not adequately monitored. Many models that predict ice-induced vibrations do not discuss this fact, hence use simple force models. In this paper, we apply multivariate analysis techniques to examine the measured force distributions on the Norströmsgrund lighthouse. As a result, we 1) identify the active force panels during ice-structure interactions, 2) demonstrate the extremely variable ice drift directions in early and late seasons, 3) show the energy contribution of each force panels and relate them to ice drift directions, and 4) reveal the dominant force modes using proper-orthogonal decomposition. The potential of a data-driven force model that captures the nonlinear nature of the force distribution in ice-induced vibrations is discussed.
Year: 2022