Back to the programme printer.gif Print



Thursday, 13 March 2014
09:00 - 10:30 Materials: Challenges and potentials
Hardware Technology  


Room: Ponent
Session description

Time is money: how can advanced materials with high potential for driving down costs be utilised in wind energy turbines within short timeframes? What can we learn from material and component testing of products currently under certification to shorten the time-to-market of the next-generation products? Does the strong worldwide competition between turbine manufacturers accelerate the use of new materials? These questions will be discussed with a view on the introduction of a new adhesive for blade bonding, testing of rotor blades, high-strength iron for rotor shafts, and superconducting materials for new generators.

Learning objectives

  • Discover ideas on how new materials support the development of new turbine components
  • Understand the interdependence between materials development, testing and product development
  • Recognise the role of testing to decrease the time-to-market of new components
Lead Session Chair:
Hans-Gerd Busmann, Fraunhofer Institut für Windenergie und Energiesystemtechnik IWES, Germany
Michael Gansow
Henkel Technologies, , Germany

Abstract

Bonding of rotor blade for wind energy plants is strongly dominated by epoxy adhesives. Epoxy technology is being used from the very beginning of rotor blade construction until know. It is considered as state of the art, and parts of very good quality are made, which is represented in hundreds of thousands of rotor blades in operation around the globe under different environmental conditions.
Of cause there are other polymers being used as well in blade bonding, such as Polyester and Methyl methacrylate adhesives and this is related to the manufacturing philosophy of the individual companies with their distinct preferences.
PUR adhesive are presently used in none structural applications e.g. the airfoil attachment in the box beam construction
Henkel is developing PUR structural adhesives, coatings and casting resins for more than 50 years and it was obvious that we were picking up this challenge to come up with new technology for a presently existing matured process. Goal was to develop a series of adhesives with the capability of fulfilling all the requirements for high end structural blade bonding with certification requirement by Germanische Lloyd. Hence a direct counterpart for the existing Epoxy technology.
Four different adhesives resulted from this research. A full reformulation of the existing PUR adhesive portfolio was required. All four adhesive went through the process of G.L. certification, lot of internal testing, engineering studies and application technology development. It became clear that the different environmental conditions round the globe required different formula.
The qualification was short cut by implementing model subcomponent development together with Fraunhofer IWES for processing, aging and fatigue studies, the Henkel beam was the result.
Right now we are in the launch phase: The developed adhesives work very well, a couple of hundred blades were made already, many full size tests were passed and we are up and running for 5 years now with no defects we know of. What we sense however is some caution on the side of some manufacturers. They like the idea of faster cure and less exothermic reactions, but they do not dare. Introducing something new is always combined with risk. There is also the hesitation to adapt their internal manufacturing processes to the needs of PUR. And for some, at least at this very moment there is no need for speed.
There are other manufacturers that are accepting these challenges and we like to thank them for this. New opportunities are also arising with the trend of segmenting blades. With new design and difficult dimensions room temperature curing polyurethanes are offering solutions which are not possible with Epoxies. And this is also valid for repair.
To summarize the outcome of the market introduction:
PUR structural adhesive are generally faster processing, having a 50% lower exothermal, low internal stress when cured, room temperature curing capability, excellent fatigue, and play out their full benefits specially in component bonding.