92 Rotor Blade Inserts strong enough for 1000kN

Rotor blades are connected to the turbine hub using bolts. The connection point needs to withstand an extremely high load. A good comparison is the max load of 50 Tesla cars pressing onto each of the bushings in the blade root at the same time.

A common bolt connection today is the threaded bushing connection. Some 92 bolts are inserted into the bushings (also called “inserts”). The bolts must have a strong anchoring point – a robustly fixed insert glued into the blade ?- to withstand the forces that the blade root is exposed to.

Withstanding 50 passenger cars

Bushings are therefore an important structural load-bearing component. Each bushing must have sufficient bonding strength capable of withstanding forces of up to 1000kN, the equivalent force of up to 50 passenger cars pulling the blade at the same time.

If the bushing is not robustly fixed, the load carrying area is reduced. This weakens the connection. Invariably this increases stresses.

This situation can over time result in loose bushings, leading to reduced life time…..like a painting falling off the wall including the plug taken out from the wall.

As a rotor blade specialist, We4Ce continues to conduct extreme load tests together with TNO.

Our objective is to quantify strength for several degrees of severity in the loose bushings.

We plan to develop criteria by which those grades of repairable bushing failure can be distinguished from?those which cannot.

For three years years, We4Ce has been working on repair solutions for loose blade root inserts. In May this year, we patented our retrofit bushing “Re-FIT” which was developed to repair loose bushings on-site in the windpark.

Our repair technology with training is offered globally together with our partner CNC Onsite

who drills out and inserts the bushing with its portable precision machines. We train our customers so they can do it themselves and have the lowest costs and the highest working flexibility.

?