Elastic-plastic behavior analysis for a flexible FOWT subjected to blade pitch control malfunction

摘要

Elastic-plastic behavior analysis methodology for a flexible FOWT is developed adopting a coupled simulation code which considers the flexibility of the floater and malfunction of blade pitch control. This paper proposes a simulation method for predicting the structural response of FOWTs when subjected to blade pitch control malfunction. The structural load and motion characteristics are evaluated in elastic and plastic regions to understand the collapse behavior at the base of the tower. A dynamic aero-hydro-structural coupled analysis method developed by some of the present authors is utilized to evaluate the elastic-plastic response of FOWTs under combined effect of wind and wave. It is found that there is significant increase of rotor thrust due to blade pitch malfunction thereby increasing tower base vertical bending moment. Further, efforts are made to understand structural collapse behavior of FOWT due to increased bending moment.