Stress analysis of the structural interface between the spar and the torus in the combined wind and wave energy concept STC

Abstract

The Spar Torus Combination (STC) is a typical concept which consists of a spar-type floating wind turbine (FWT) and a torus-shaped wave energy converter (WEC), which utilizes the wind energy and wave energy simultaneously. The STC concept reduces the capital costs and improves the utilization of the ocean energy. The study focuses on the interface between the spar and the torus. According to the previous numerical and experimental studies, the interface is expected to undergo extremely large wave loads . The "roller-guide" interface is designed and established in ABAQUS. Nonlinear local structural modelling of the interface is carried out in this thesis. The WEC is established to be connected to the spar cylinder with designed rollers and hydraulic supports. Rubber rollers and spring connectors are used to absorb the wave energy so that the contact stress in the interface is not significant. Different scenarios are defined to investigate the performance of the interface structure. Quasi-static analyses are performed, and the elementary dynamic effect is investigated. The results have been discussed in this thesis.