New method to discover how cracks and failure evolve in composite material used for wind turbine blades

Friday 09 Mar 18

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Lars Pilgaard Mikkelsen
Head of Section Composite Mechanics and Structures
DTU Wind Energy
+45 46 77 47 09

DTU Wind Energy and LM Wind Power have joined forces in the project CINEMA, where the focus is on discovering how fatigue damages evolve in glass composite material used for wind turbine blades.

DTU Wind Energy has in a collaboration with LM Wind Power found a new method to observe how fatigue damages evolve in the uni-directional glass-fibre reinforced composite materials used inside wind turbine blades.

Throughout the project CINEMA, the researchers explore the possibilities to extend the lifetime of wind turbine blades by the use of 3D x-ray computer tomography. The more knowledge, the researchers gain about damages in wind turbines blades, the better they will be able to develop more competitive materials and improved wind turbine blade designs, says Lars Pilgaard Mikkelsen, lecturer at DTU Wind Energy:

“This is the first time it has been possible to use 3D x-ray computer tomography scans to look at the development of fatigue damage at a micro scale in the glass fibre materials used as the load carrying laminates inside wind turbine blades,” he says and continues:

“The new technique makes it possible for us to identify, how and where the damages begin, and how they develop, when the composites are being exposed to an increasing number of load cycles throughout its lifetime.” 

A new breakthrough
The new 3D x-ray computer thermography is a ground-breaking way to look at the development of damages. Only a few years ago, similar analyses were based on destructive analyses, where you had to slice the material in order to look inside it using e.g. a scanning electron microscope. Thus, you only got a snapshot in two dimensions and you did not have the possibility to look at the damage evolutions.

Jens Zangenberg Hansen, Senior Engineer at LM Wind Power says that the tomography opens up for new and improved possibilities:

“We have, through the CINEMA collaboration, identified a number of fatigue damage mechanisms that we only have had some hypothesis about before. It is relevant for us to know our materials and the ways they develop damage in order for us to optimize our products. That is the only way for us to make even more reliable wind turbine blades ready for the green energy in the future.”