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A lifting yoke made of GRP composite

News International-French

19 Apr 2016

The large lifting yoke used by Eltronic for offshore operations is a heavyweight construction, therefore they teamed up with Fiberline to find a lighter solution made of GRP composite instead of steel.

"We simply had to reduce the weight," explains Kenneth H. Svinth, CEO at Eltronic Heavy Industries, describing the problem and its solution. The lifting yoke is used for installing individual blades on offshore wind turbines, and Eltronic's customer wished to switch to using a faster and smaller crane for the task. This could only be done by reducing the weight of the yoke. Eltronic therefore contacted Fiberline Composites to discuss a solution using GRP profiles, which in direct comparison with steel weighs only about 25%.

It was an essential requirement that the new GRP construction should be every bit as safe to work with as the steel original. Much of the manual work takes place at a height of eight metres, and Eltronic guarantees that the turbine blades, which are 75 metres long and weigh 25 tonnes, can be lifted into place in wind speeds as high as 14 m/s.

Another aspect, which although not a direct requirement from Eltronic has subsequently proved to be a major advantage, is the durability of GRP. "Visually, steel degrades rapidly in the harsh offshore environment, says Kenneth H. Svinth, "but this is not the case with GRP composite, which looks the same whether it has been at sea for two days or two years.”

To date, the collaboration between Eltronic Heavy Industries and Fiberline Composites has resulted in five GRP platforms.

Weight and durability
The use of GRP profiles in offshore constructions is becoming increasingly commonplace. Above all because GRP is non-corrosive and considerably lighter than e.g. steel. In direct comparison with steel, GRP weighs around 25%. When the total GRP volume is taken into account, Fiberline's customers usually end up with a weight saving of about 50%.

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