Finite element analysis of newly designed monopiles for offshore wind turbines on seabed with shallowly buried batholith

ABSTRACT

In this paper, three types of hybrid monopiles are proposed for 3MW OWTs in offshore areas where the batholith is shallowly buried. Three-dimensional FE models are established considering the soil-structure-interaction (SSI) to calculate the bearing performances of these monopiles. Model verification is conducted through comparisons with existing numerical results. The static bearing performance and dynamic character under the serviceability limit state (SLS) in silty sand and normally consolidated (NC) clay are investigated. In the static analysis, we focus on the lateral deflection and the rotation at the mudline, whereas in the modal analysis, we focus on the natural frequencies of the OWTs. Results show that the circular skirt performs better than square fins in improving the bearing performance of traditional monopiles, and the improving effect increases with the length of the additional components. In addition, the improving effect is more obvious in NC clay than in silty sand.

KEYWORDS:

• Hybrid monopile
• soil-structure-interaction (SSI)
• model verification
• static response
• natural frequency

Acknowledgements

This work was supported by the Natural Science Foundation of Jiangsu Province [grant numbers BK20190970, BK20190974].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Natural Science Foundation of Jiangsu Province: [Grant Number BK20190970]; Natural Science Foundation of Jiangsu Province: [Grant Number BK20190974].