Adhesives bond critical wind turbine components
The planned ban on petrol and diesel car sales by 2040 will change the automotive industry landscape. Whilst the announcement of petrol and diesel vehicles being banned in Britain by 2040 was met with scepticism in some quarters, it cannot be denied that change is on the horizon, especially with Government insisting there is “no alternative to embracing new technology”, due to the damage harmful emissions are causing to the environment.
Looking up at the 80m tower of a wind turbine is a humbling experience, like staring up at a cathedral spire. But with the vast 20m blades spinning gently round, this unique blend of aerodynamics, architecture and engineering is even more impressive. Yet compared to the latest wind turbines, it is almost a miniature model: the new-generation turbines have blades 60m long that are mounted on a tower 135m high, which is as tall as a 35-storey skyscraper. But because you cannot make the wind blow harder, you must make the blades bigger, and massive 90m blades are currently in development as the wind energy industry strives for greater efficiency and return on investment.
Most blade producers use epoxy resin to bond the various components, but Henkel recognised that this technology has its limits and introduced Loctite UK 1340 BX, a polyurethane (PUR) adhesive. “What sets this apart is that it combines high-performance bonding with excellent wetting capability, which makes it easy to use. This product is quite simply a quantum leap forward for PUR adhesives,” says Hartmut Pilz, industrial assembly market manager for wind, EMEA, at Henkel. “It cures much faster than epoxy. This allows more blades to be produced in the same amount of time and with less energy. As the industry becomes more automated, our product will be in greater demand.”
Loctite UK 1340 BX also has a low exothermic peak; hence it reduces heat stress to components as well as shrinkage, which means it is far less likely to crack.
“Rotor blades are among the most highly stressed components you can imagine,” explains Nicole Schlingloff, product developer at Henkel. “Even the tiniest flaws can have disastrous consequences – replacing a set of rotors can cost several hundred thousand euros, not to mention the downtime. That is why we had to make sure that Loctite UK 1340 BX would meet the highest demands.”
To see just how strong the new PUR adhesive really is, the Fraunhofer Institute for Wind Energy and Energy System Technology in Bremerhaven, one of the world’s top inspection bodies, tested a blade constructed by Enercon, one of the world’s leading producers of wind turbines, using Loctite UK 1340 BX. The 40m blade weighing 9 tonnes was subjected to trials designed to simulate 20 years of service life. Over three months, the blade was bent 1.2 million times flap-wise and two million times edge-wise.
But that was not all – before and after the dynamic tests, the blade was bent with a force equivalent to four huge 40-tonne trucks to simulate a “storm of the century” (a 250km/h wind for two hours). The blade not only survived, it went on to pass stringent IEC tests and met Enercon’s own demanding requirements.
But strength alone is not the only measure – other factors like tensile shear strength, resistance to ageing, creep behaviour and glass transition are also critical. Germanischer Lloyd of Hamburg, the leading international certification body for shipping and energy, put Loctite UK 1340 BX through a year of comprehensive trials, and it became the first PUR to get Germanischer Lloyd certification for this type of blade bonding. “The tests are conclusive proof that Henkel can deliver innovative, high-performance solutions for the wind industry,” says Schlingloff proudly. “And we know we have a product that will improve quality and productivity while also cutting energy and maintenance costs.”
Other News from Henkel Ltd
Latest news about Adhesives