Blade Wrinkles Explained with Morten Handberg of Wind Power LAB

Allen Hall discusses the growing issue of blade wrinkles with Morten Handberg, blade expert at Wind Power LAB. They delve into the causes, consequences, and challenges of identifying and repairing these minute deformities that can significantly reduce blade life. Visit https://windpowerlab.com/!



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Allen Hall: Welcome to the special edition of the Uptime Wind Energy podcast. I'm your host, Allen Hall, and if you have been following the news lately, there are several ongoing campaigns by blade manufacturers to deal with wrinkles in their blades. Even though these wrinkles are minute in appearance, these fabric deformities can create weaknesses that reduce blade life.



And as you have seen all over the news, these wrinkles are also expensive to remove and repair. Our guest is Morton Handberg, Chief Blade Specialist and Partner at Wind Power Lab, which is a blade consulting company located in Copenhagen, Denmark. If you haven't heard Morten on our podcast previously, Morten is our resident blade whisperer.



In our episode today, we'll be discussing how wrinkles are created, how they produce stresses, and why they are difficult to eliminate during manufacturing. Morten, welcome to the program.



Morten Handberg: Hi Allen,



Allen Hall: it's nice to be back again. If we can catch up a little bit, you and I talked to each other about Blade Wrinkles several weeks ago now, and that topic has just gotten progressively hotter and hotter.



I thought, now's the time. To get it out there about what's happening with wrinkles and why we should care. Now, and at the same time, you sent me some pictures and it would just scare the heck out of me because I thought these wrinkles were relatively small coming from an aerospace background.



Wrinkles don't tend to be big. In aerospace products, but the wrinkles you showed me are large. And I'm trying to understand like what is the real threat here? Let's just start there. What's the real threat. If a wrinkle is in a side of a blade, what does it matter?



Morten Handberg: So it really matters depending on the location of the wrinkle.



So is it in the structural spark cap or in a heavy node, part of the bait, let's say the root or the transition zone. Then even small wrinkles can actually turn into very large cracks. And it doesn't really matter what the size is. It's more, if it's in an area that allows it to grow into a crack, because as soon as it does that, it will just continue growing at a pace defined by the loading conditions, it can ultimately turn to a blade failure.



Obviously, the larger and more aggressive, the cracking the wrinkles, meaning how how steep the angles are of the wrinkles. So if this is the shape it matters that the wrinkles is shaped like this or like this. Then how much stress it requires for it to develop, because it's all about the, how much reduction that it creates to the to the underlying blade structure.



If you have changes in the UD laminate and it starts to fold, it means that the strength of the UD laminate is reduced. And then it's just about a matter of time before it then turns into a structural crack.



Allen Hall: And the defect doesn't just apply to the plies where the wrinkle is, it applies, it puts additional stress on the plies that are around it?



Is that the loading problem?



Morten Handberg: Yeah, because, if you remove the loading capacity of one area,