Cost reduction is an important topic in the offshore wind sector. However, in view of the move to larger turbine sizes and deeper waters, costs of foundation structures will rise. MSC has developed a welding specification increasing the fatigue performance of a welded joint. Demonstration of the real fatigue performance is actually as important as the welding technique, and a faster testing technique was looked for..
A testing technique based on the resonance principle was developed. After an initial finite element study, a medium scale specimen was tested in an existing installation. In view of the good results and match with the numerical simulations, the upscaling of the node fatigue testing rig, called CRONOS, was performed together with in-house and external engineering teams.
It is now possible to test tubular joints having the dimensions of offshore wind turbine jacket structures at millions of cycles within a week and with low energy consumption. The test methodology has received support from certification authorities for its use in qualifying full scale nodes from the supply chain on their real fatigue performance.
Node fatigue testing rig CRONOS
Resonant bending rig