R&D Test Systems: Digital Twins for Wind Turbine Testing

Allen Hall and Joel Saxum interview Dr. Elif Ecem Bas, a PhD
project engineer at R&D Test Systems in Denmark. Dr. Bas
discusses how R&D Test Systems is leveraging digital twin
technologies and hybrid testing to improve the efficiency and
effectiveness of testing wind turbine components, particularly
pitch bearings. Sign up now for Uptime Tech News, our weekly email
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www.weatherguardwind.comIntelstor - https://www.intelstor.com Allen
Hall: Welcome to the Uptime Wind Energy Podcast. I'm your host,
Allen Hall, along with my co host, Joel Saxum. As wind turbines
grow in size and complexity, testing these components has become
increasingly expensive and time consuming. To address these
challenges, R&D Test Systems is leveraging digital twin
technologies to improve the efficiency of their test bed. Benches,
ultimately reducing testing time and costs. And if you don't
already know, R&D Test Systems is a leading company in the wind
energy industry, providing testing solutions for wind turbine
components on a massive scale. Today we have the pleasure of
speaking with Ecem Bas, a PhD project engineer. At R&D Test
Systems in Denmark, Dr. Bas earned her PhD in structural
engineering from the University of Nevada, Reno, and is currently
focusing on digital twin technologies at R&D Test Systems. In
this interview, we will delve into the applications of digital twin
technology and wind turbine component testing and learn more about
Dr. Bas's work in this cutting edge field. Ecem, Welcome to the
program. Elif Ecem Bas: Thank you. And thanks a lot for the
introduction. Allen Hall: So there's a lot to learn here because
Joel and I have been following the digital twin saga over the last
several years because you see a lot of of news articles and
information about digital twins and OEMs or have been looking at it
and a lot of smaller companies have been trying to prove out
digital twins. But we haven't seen a lot of it being applied in a
place where I think it's important, which is in the testing phase.
And R&D Test Systems if you haven't worked with R&D Test
Systems, build some of the largest pieces of test equipment in the
world to test generators up to 25 megawatts and all kind of blades,
just insanely big things. So what is the benefit of using Digital
Twin on such large test equipment? Elif Ecem Bas: Let's come one
step back. As you mentioned in your introduction. Testing is
necessity for all the wind turbine components and their
subcomponents as well. This is required by the standards and this
is required by the design and also the manufacturing. So we will
not get rid of testing. Testing is very important. But as the wind
turbines are getting bigger and bigger, this time to test these
components takes also a lot of time. And for as an example for a
blade to test the Fatigue test to make a fatigue test for a blade.
It takes one year or more than a year to do the saw Joel Saxum:
Constant movement. Elif Ecem Bas: Yeah, exactly to see all the
damages through the blade. You have to do that and also for a
highly accelerated lifetime testing of an assault. This also takes
six and eight months and also testing this. These are large
facilities, right? And testing this will also cost money. tens of
million euros bought to establish and run this. And this leads, of
course, longer time to market. For new and more powerful wind
turbines. In detail systems, we are trying to develop digital tools
to overcome these challenges and to have these turbines to roll
onto the market. So and also yeah, cut cost on it. And what we are
using digital twins in the testing, it is very necessary because we
would like to reduce the cost of the down time in the testing
itself, in the test execution itself. Allen Hall: So there are
portions of testing, from my understanding, and I'm an electrical
engineer and I'm a mechanical engineer, but I've spent about a lot
of structural testing. Those tests take a long time, they're very
expensive, but sometimes the result we get out of those tests isn't
very useful in the real world. On the other side of this, you've
got two problems. One is that, does the test match what's happening
in service? That's a really great question. The second half is, how
much do you know about this product before you start testing it? Or
are you testing the way? You're touching the engineering aspects
properly to evaluate that for the real world. And I think you, you
run into two problems here and I want to understand this part
first, which is you model the component, but you don't model all
aspects of it. And I want to, I Can you walk through that a little
bit, like what you're trying to do with a device, a blade, or a
gearbox, or anything else, a pitch bearing? Elif Ecem Bas: As you
mentioned, there are two aspects. So in the component test, we just
take one component and test it, right? And with our, Digital twin
technologies, we focus on both simulating the complete system,
whereas we only test one component and model the remaining parts.
So this is one thing, and we call this hybrid testing because one
part is tested experimentally, whereas the remaining components are
modeled numerically. And we do this in In a closed loop system
where we share at every time step, we share the commands and
feedbacks with the test bench. So this is one aspect where we test.
Only one component, let's say it is the pitch bearing, and model
the remaining part, which is the blade and the hub and the other
parts, the other blades. Allen Hall: Alright, so that's
interesting. That's a complicated model though, right? When you try
to do that. Elif Ecem Bas: Exactly. Allen Hall: So you have to
simplify it so you can model it. How are you finding those sort of
the key characteristics so you can model it on a test bench
properly? Elif Ecem Bas: Why we do hybrid testing? Hybrid testing
is to get the both advantages from the experimental world and from
the analytical world. So we do hybrid testing for the components
that we cannot model properly. In this case, it is, we choose that
it is the pitch bearing because it's very hard to model. Joel
Saxum: Makes sense. Yeah. Yeah. Elif Ecem Bas: Yeah. And also the
pitch bearing itself. So bearings are designed to roll, right? But
the pitch bearing is rolling a little bit and then exposed to the
bending moments for their lifetime. So it's against to its own
nature. So this is why also predicting the failure mechanisms of
the pitch bearing is a bit hard. Another thing is, when it is
failed, it is very hard to backtrace what was the cause of this
failure, because you cannot model it properly. So what we are doing
is, since this part is hard to model, we put it in an experimental
setup. And the blade and the remaining part, the other kinematics
are relatively easier to model. Joel Saxum: That's a good word.
Relatively. Yeah. Elif Ecem Bas: And so it took that part and we
use that simplified models to apply more realistic loading
scenarios to the pitch bearing. In order to get its behavior. Joel
Saxum: A question here like Allen said earlier pitch bearings is a
headache for, man, what would you say, 90 percent of the people we
talk to, Allen? Oh, easily, yes. When we're thinking about you guys
advancing the testing mechanism for us, because it's, it is, just,
if you picture it in your head, It is, a bearing is designed for
that rolling surface, however, this not only is exposed to the root
bending moment of the blades, basically, on a fulcrum, pulling and
pushing on it, but it's also having gravitational loads at the
exact same time, going up, sideways, down so you have this really
complex load scenario. You guys coming forth with something that
could hopefully accelerate lifetime testing, Elif Ecem Bas: Yeah.
Also, we are looking into testing extreme cases in this scenario.
So picking up extreme wind load event and test this and hopefully
see the development of a failure with the test. Joel Saxum: That
with everybody with pitch bearings. If you talk to anybody in the
manufacturing sector, it's it's really hard to do an accelerate at
any kind of lifetime testing. For that pitch, because it isn't when
you look at it in the crate, right? That is a robust piece of
metal. That's a big, bad thing, right? If anybody's ever seen one
of these it's impressive how big it is and how heavy it is and how
much steel there is. But to test that you can't you can't do a life
cycle test in six months on that thing. It's just not possible.
Elif Ecem Bas: Exactly. And also what. We hear from the test
centers that they cannot see the failures with this highly
accelerated lifetime test on it. So what we are looking into, okay,
we have this extreme load case scenario. Can we apply this with
hybrid testing and can we see the development of the failure of
this component? Allen Hall: Let me ask you about the complexities
of pitch bearing, because I think Joel brought it up at a really
high level, but I want to focus in, drill down to how complex this
is. So you have this massively long blade, right? The blades are
getting longer, so the center of gravity is moving further and
further out, the center of lift on them is moving also, the blades
are flexing, right? Then you got the gravitational pull. piece. But
on top of that, now you've added a control system in the turbine,
which is pitching the blades as they rotate around the 360. So you
have this,