Siemens, Munich, began to investigate composite materials for nacelles used on its new 6 MW offshore wind turbines. In particular, a composite maintenance hatch had been designed to replace a steel panel and traditional bolt fixings were used to lock and unlock it. This required two people to perform the operation – one inside and one outside the nacelle. Clearly ease of access and its related safely were problems to be solved, in addition to reducing maintenance costs. Siemens nacelle suppliers approached UK-based BigHead Bonding Fasteners Ltd. and together developed a solution.
By surface bonding the 316 marine-grade stainless steel BigHead to the outer skin of the nacelle and passing the threaded stud section through its composite structure, the panel is easily secured or removed by a single person from the much safer interior of the structure. The BigHead’s large perforated head allows a generous flow of adhesive to firmly secure it in position and its outer surface includes an over-molded insulation layer that safeguards the nacelle against lightning strikes as well as match its color.
BigHead worked with the customer through a stringent development stage - prototyping and extreme testing the solution against the harsh conditions that the offshore wind turbines need to endure until a final design was agreed. Now in its third year of supply, the solution has been thoroughly field proven. Like all BigHead’s produced at its Verwood, UK factory, every production batch is tested and documented with completely traceable results as part of the manufacturers ISO 9001:2008 Quality Management System.
BigHead have been manufacturing its brand of discrete bonding fasteners for over 50 years and has experience across a wide range of industries where formed and molded composite products require discrete and completely secure fixing. Applications range from carbon fiber panel fixing in specialist and luxury car production to building and construction, railway carriage construction, marine and boatbuilding and more.