The WrapNode-I project focuses on investigating the use of wrapped composite joints in offshore wind turbine support structures, aiming to reduce costs, weight, and production time. The project aims to enhance fatigue resistance and decrease the amount of steel required by employing composite joints instead of complex welded joints in jacked foundations.
With the increasing size and depth of offshore wind farms, monopile foundations have become larger, heavier, and more expensive. Jackets, which are lighter alternative support structures, face challenges due to complex welds, resulting in higher costs and longer production routes compared to monopiles. The WrapNode-I project addresses these challenges by exploring the use of wrapped composite joints in jacket structures. These joints offer increased fatigue resistance and reduce the amount of steel required, leading to potential cost reductions of 25% to 50% for supporting structures.
The WrapNode-I project aims to demonstrate the technical and economic feasibility of using wrapped composite joints in offshore jackets. This is done by conducting full-scale joint tests, testing the environmental influences and multi-axial loading on the joints, optimizing the performance of the joint components, and proposing prediction methods and design procedures for static and fatigue performance. Through these activities, the project seeks to provide a solid basis for the implementation of wrapped composite joints in offshore wind turbine jackets.
Experimental Progress at TU Delft
TU Delft conducted experiments in the WrapNode-I project to assess the WrapNode joint's resistance to static and fatigue loading. Tests were performed on multiple scales to understand scale effects. Over 300 coupon tests examined temperature, ageing degradation, and saltwater impact. In the Hexapod specimens were tested on multiaxial behaviour, while a new fatigue testing rig was used to evaluate double-k joints. These experiments provided valuable insights into the structural behaviour of the WrapNode joint.
Within the WrapNode-I project, we work with several partners, including Tree Composites, Shell, Siemens Gamesa, Vattenfall, AOC, BUEFA, Enersea, GROW, HSM Offshore Energy, Salzgitter and Smulders. These partners collaborate to support developing and implementing wrapped composite joints in offshore jackets.