Accelerator spotlights jacket fatigue

The Carbon Trust’s Offshore Wind Accelerator (OWA) has launched a new project aiming to optimise the design of jacket foundations through improved fatigue standards and validation of faster testing and fabrication methods.

The £2.4m Improved Fatigue Life of Welded Jacket Connections (JaCo) project targets a better understanding of fatigue performance, OWA said.

It said the three-year project will test full-size jacket nodes made from existing manual and novel automated welding processes.  

“Coupled with improved standards it is estimated that a weight reduction of 10% can be achieved if the fatigue resistance (strength) is enhanced by 10-20% through optimised design,” OWA said.

It added that the industry trend towards deeper water and larger wind turbines presents an opportunity to optimise jacket foundations, which consist primarily of welded tubular space frames fabricated in steel.

Each welded connection point is termed a node and fatigue at these welds is an important design consideration that often proves to be the limiting factor, OWA said.

The project will include collaboration between developers, supply chain, research organisations and government, with Belgian material research centre OCAS providing testing techniques to reduce the time needed to complete fatigue tests. 

The project will also be guided by a panel of independent experts, including Cranfield University, DNV GL, Bureau Veritas and the Federal Institute for Materials Research and Testing, OWA said.

Carbon Trust director of offshore wind Jan Matthiesen said: “With an increasing trend of larger turbines that will be installed in deeper waters, we will see a growth in the use of more economic jacket structures.

“We have launched this project to drive cost reductions by optimising such structures.

“In addition, this project will aim to demonstrate the performance of robotic welding, which will allow the supply chain to fabricate at industrial scale.”

Image: Carbon Trust