An application of Structural Health Monitoring system based on FBG sensors to offshore wind turbine support structure model

The paper presents an application of Structural Health Monitoring system based on Fibre Bragg Grating sensors dedicated to an offshore wind turbine support structure (tripod) model. The experimental investigation was performed in a water basin for the wind turbine model fixed to a turntable that allowed to change the angle between the tripod legs and a wave generator direction. During measurements the structure was excited by artificial waves and rotor blades rotating simulating effect of wind blowing with different strength. The excitation simulated environmental loading typical for offshore wind turbine. One of the tripod's upper braces contained a flange simulating artificial circumferential crack occurrence. For the structure under simulating environmental condition four damage indexes (relative and absolute) were developed that allowed to detect the damage and localise it with accuracy to the tripod's leg.