We have discovered the problem!
Posted on 02/02/2023 9:56:52 AM PST by Leaning Right
The taller the wind turbine, the harder they fall. And they sure are falling.
Wind turbine failures are on the uptick, from Oklahoma to Sweden and Colorado to Germany, with all three of the major manufacturers admitting that the race to create bigger turbines has invited manufacturing issues, according to a report from Bloomberg.
(Excerpt) Read more at popularmechanics.com ...
yup
i shudda read ahead!
We have discovered the problem!
After bolting, why didn’t they just WELD the flanges together?
You would have to admit to the boss that you screwed up to have them ordered.
Better to just glue the bolt heads back on and hope for the best.
On a nuclear sub. God help us.
Miles of them tipped over like these?
Use crazy glue or JBWeld. Everything is o.k.
God says, Call on somebody that knows you. I don’t know you, boy. You kicked Me out of everywhere.
Chic Engineers. Wanna bet?
I wonder what the internal structure looks like. I think it could be harmonic resonance and the stress concentrates at certain points within the structure and weakens it.
Per the headline; “This shouldn’t be happening.”
Because we shouldn’t even have them around anymore as they have proven to be ineffective.
Are they using the highest grade bolts possible or not getting the proper high grade bolt installed?
They kill birds:
https://www.youtube.com/watch?v=5lb6VeMaXy8
In other words, the bolts failed because the tower leaned over, the tower didn’t lean over because the bolts gave out. The bolts were stretched beyond their yield point.
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It’s fun to speculate when dealing with ‘crash dynamics’ and your third picture at post 18 probably wasn’t the best example for the point I was trying to make….or at least it’s more complicated than I was suggesting. With other IWT crashes I’ve seen where it appears that the bolts at the flanges have just departed (like your 3rd picture), the surfaces where the bolt separation has occurred have the classic striation markings which unmistakenly identify them as bolt fatigue failures…or at least fatigue is present even if the fatigue fracture happened secondarily to something else but failed anyway because of being in a severely weakened state. Thus when a ‘clean flange’ is seen like in the picture, fatigue is automatically assumed. Having said that, you raise a good point which is essentially… what came first and what explains the fold in the tower.
Let’s say the fold happened first for some reason…. Towers are design for some serious wind speeds as worst case scenarios and that is likely to be in the 100 to 150 mph range depending on where this one was located. I don’t know where this failure occurred and whether there was some unusual ‘500 year event’ that occurred…. If you know the details of location and date, a survey of some archived weather data would give you the wind speed data you need. Regardless, if high wind speed played a role in the sense that it had increased to the point of the tower failure, all the flange bolts on the windward side would have seen an increase in tensile stress. However, at the instant that the tower gives way and folds, that additional tensile force in the bolts drops instantly… essentially the restraining force they need to provide is dramatically reduced. Thus the folding of the tower didn’t happen first… the only thing that could have happened is that the fold in the tower and the popping of the bolts essentially happened at the same time but that would mean that a scenario was encountered where the stresses at the flange bolts are increased. That of course would be very difficult to believe unless the bolts were already at the point of failure anyway. It needs to be remembered that the flange joint is designed to be at least as strong (or stronger) than the rest of the tower… thus if there were still forces going on after the fold that could cause a secondary failure in the tower, it wouldn’t happen at the flange joint but at some point between the flanges. Here’s another scenario… let’s say a blade flew off for some reason and put the entire tower into a wild state of imbalance. There are two outcomes from that… one is that the onboard vibration instrumentation will ‘put the brakes on’ and this has been known to create a reaction that is so severe that it can bring a tower down. Or there is the scenario where the out of balance forces were serious enough to cause the fold… if either of those occurred, then it would just fold over and everything from that point on up would just crash to the ground. What would cause the bolts to fail since the tensile forces would be reduced as soon as the fold occurred.
Now, you didn’t say that it failed due to high winds…. It could have buckled for some other reason but it starts to get very difficult to envision other causes for the fold. If for example, the foundation let loose and failed, the whole tower will just fall over without a folding of the tower…. and I can show you many pictures of those. There is one cause I’ve seen a few times that caused a tower to fold and that is if it was struck by a blade…. and I think that there is a good chance of it happening in this case. I think it’s possible that the first part of the sequence was that the flange bolts failed and it started to fall around what I referred to as the ‘hinge point’. At some point, inertia and the rotor gyrsoscopic effects play an important role… and after the failure at the flange had already happened, a blade may have clipped the tower and caused it to fold. In that sense, it’s like a pop can that is reletively stiff when weight is applied from above but very weak if a force is applied to the side of it.
The picture looks vaguely familiar. Is this one that failed in Oklahoma a year or two ago… north of Oklahoma City an hour or two as I recall?
After bolting, why didn’t they just WELD the flanges together?
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Good question but they probably don’t because of cost and because there are other implications to welding them up. As well, fatigue will still happen as long as they are above the endurance limit... it just delays the onset of fatigue cracks.
Are they using the highest grade bolts possible or not getting the proper high grade bolt installed?
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I suspect they are using the best bolts they can get their hands on. There is a very stringent bolt tightening protocol they are supposed to follow that involves a schedule of checking the torque at various points in time after installation... I’m not sure how well that gets followed and I’ve had my suspicions with a few failures that I’ve seen.
However, this is no different than bending a paper clip back and forth until eventually, it cracks. There are parameters that you can change that will provide a different number of cycles before it will crack but if the stresses are above the endurance limit for the metal in question, it will eventually fatigue. I suspect that most of the IWTs that are out there, the bolts simply have to be changed out every X number of years and that’s all there is to it.
NO.
Simple physics.
Essentially those wind turbine propellers create centrifugal force. Anything that “cycles” creates this force from wind turbines to basic electricity.
Ever have a thing as tiny and simple as a light bulb, suddenly flickering on/off and is loose in the socket? OR you go to remove a burnt out light bulb you know you never put in that tight?
Yes, wind is energy. And contrary to what the environmentalists want you to think, there is a payment due for using it beyond natural resources.
The payment comes in the form of basic 101 Physics. Enough force will loosen the windmill from it’s base. And that force will come as too high of winds or too long of winds.
Lifetime maintenance costs exceed the value of power produced.
But who knows why the price of electricity is soaring? It’s a mystery.
New bolts wont help, as the tubes themselves are breaking.
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