Experimental study on dynamic characteristics of the jacket-type offshore wind turbine under wind and collision loads

Jacket-type offshore wind turbines operate in complex marine environments. During operation, these structures are influenced not only by wind loads but also by collision loads caused by ships and ice. The wind and collision loads cause significant structural vibrations and deformations, affecting structural lifespan. Therefore, this study conducted experimental research on the dynamic characteristics of jacket-type offshore wind turbines under wind and collision loads. The research results show that under collision loads, the structural response is mainly concentrated in the platform first-order frequency and the tower first-order frequency's triple frequency. Under the wind and collision loads, wind loads suppress tower vibrations caused by collision loads. Influenced by wind loads, the jacket platform's damping ratio significantly decreases. The structural capacity to dissipate the collision energy significantly diminishes. The wind and collision coupling effect is significant. The tower top shear under wind and collision conditions is less than the tower top shear's linear superposition value under the individual wind and collision loads. The load combination characteristics of the tower top shear are significantly influenced by the rotor thrust. The tower top shear should be separated into wind-dominated and collision-dominated regions for structural design.