Bolted flange connections are one of the most common and critical mechanical joints within a wind turbine support structure. They join almost all wind turbine generator towers to their foundations, and increasingly are becoming standard for monopile (MP) to transition piece (TP) connections, particularly since problems with slipping grouted connections were discovered around 2010.
Whilst there are obvious benefits to a bolted flange (such as a direct load path), there are also some difficulties to be overcome. For instance, bolted connections are sensitive to corrosion and must be robustly protected from the marine environment to ensure their longevity.
The bolted flange is not a new development, yet there are many areas in which they can be improved. Ultimately any improvements in methods – be that design, manufacturing, installation, O&M or even decommissioning – can help reduce the cost of building and operating an offshore wind farm. It is the aim of this study to identify the areas where the cost benefits can be gained most effectively through targeted research efforts.