Hits:

Indexed by:Journal Papers

Date of Publication:2015-06-01

Journal:APPLIED OCEAN RESEARCH

Included Journals:SCIE、EI、Scopus

Volume:51

Page Number:129-137

ISSN No.:0141-1187

Key Words:Crashworthy device; Optimization design; Dynamic effect; Monopile foundation; Offshore wind turbine; Ship collision

Abstract:The risk of offshore wind turbines collision with ships is on the rise during the service period with the increase of offshore wind farms and ship routings. In order to minimize the damage of offshore wind turbines caused by ship impact, a crashworthy device, which contains a rubber blanket and outer steel shell, is proposed. The rubber hardness and the rubber and steel shell thicknesses of the crashworthy device are optimized by comparing the collision-force and nacelle acceleration using LS-DYNA explicit code. The main reason for lessening the maximum collision-force and nacelle acceleration is that the rubber blanket could absorb a portion of ship energy by using its own structure deformation. Therefore, an optimal crashworthy device for the monopile offshore wind turbine, meeting the weight constraint, is suggested and implemented in various impact scenarios. The obvious effects of crashworthy devices are a decrease of the maximum collision-force and nacelle acceleration, especially for ships with smaller initial kinetic energy. The damage area of plastic strain for foundations is reduced to zero when crashworthy devices are used in the analysis scenarios. This paper may be useful in anti-impact design of offshore wind turbines. (C) 2015 Elsevier Ltd. All rights reserved.