January 6, 2021
A conversation between Pipe Stress Engineers
Luuk Hennen 10:30
All right. So we are live.
Welcome everyone to this first live stream of EngineeringTrainer.com. My name is Luuk, Luuk Hennen, and I'm the founder of EngineeringTrainer, an online training platform for engineering professionals worldwide. And today I'm going to have a discussion where we are going to have a discussion with Sondre Luca Helgesen. Sondre was the founder of Stressman engineering and currently holds the position of CEO. And he's also the Regional Director of the psi Association in Scandinavia.
I mean, it's going to be an interesting discussion, we're going to have discussions on load case out, gaps, clearances, nonlinearities, we'll do so by having a look at one of the Stressman engineering projects.
I'm actually really glad that you all joined us, and I want to invite you to join us in the chat as well. I mean, you know, let us know you're out there, ask questions. So hi, hi, Jess. Hi, Mangi. Thanks for you know, sharing that you're there.
And I also want to like to invite you to, you know, head over to the LinkedIn accounts of me and Sondre connect with us, you know, ask questions, hello, say it's nice to have you as well as questions, you know, interact with us, and we'd be happy to show you you know, the stuff that engineering trainer.com and also Stressman engineering is doing, you know, the best way to stay aware of these live streams is just to follow the YouTube channel as well. And having said that, I give the word, you know, to Sondre, how are you doing?
Sondre Helgesen 12:29
Hey, I'm doing good.
Luuk Hennen 12:31
Well, I'm really glad to have you. I mean, we've been discussing, we've been having discussions on five stress topics like, you know, about a year now, every now and then. And every time, you know, that we sparked so much, you know, enthusiasm, and it was great technical conversations. And we just came up with the idea to you know, just do it live and just see what happens, just you know, goes on the content and real technical topics. And you see if people have questions, if they, how they join us and how they interact with us. The recordings of these sessions will be available, you know, later on, on our YouTube channel, etc. But we're really happy for those that joined us during this live session.
So how are you doing? I mean, you must be pretty busy preparing for the live course that's coming up this February. Yeah, it's always like this, this great feeling. You know, when you have these courses, I've been hosting all the live classroom courses before, in pipe stress. This one is going to be a bit different because it's going to be the first online course that we're gonna have. So it feels like butterflies, you know, in the stomach. So it's really cool to have that opportunity. And we've been asked for this for so many years now. It's like, every time we hosted a classroom course, people have been asking, like, why can't you do it digitally online? And to be honest, I like to travel. So I like to see the places and the people, but now due to this virus that keeps everybody at home? Yeah. Well, it's gonna be a great opportunity to do that. Perfect, perfect. We have had a great response so far. And just so you know, make the viewers aware. those that haven't seen it yet. Stressman engineering is hosting the five stress fundamental scores that they gave in a classroom format for the past couple of years as an online course on engineering trainer.com.
You know, if you want to know more about it, we currently run for all the viewers of this live stream, we actually run a discount offer. So you know, if you want to know more about that, I recommend you head over to the engineering train.com Let me show you.
Head over to engineering training.com. If you scroll down from the homepage, you'll see the five stress fundamental scores popping up and if you go there you see
There are two courses with a total of 16 hours of content. And they're bundled in a product that is available on engineering trainer.com. But make sure to use the discount coupon if you're watching this, it will save you around a little less than 10%. Having said that, you know, let's jump into the real content of this conversation. And I guess we'll be discussing a little bit more of the course that is coming up maybe at the end of this live stream. All right. Okay, so Sondre, I'm gonna share your screen. If you're alright. So it will mean you have to close the Livestream yourself. Otherwise, people will see me. Yeah.
Sondre Helgesen 15:52
Yeah, yeah, I'm looking into infinity. So are you sharing my screen right now? Yeah, yeah, people can see. Yes, perfect. So I just wanted to give you a quick background of Who am I and who is Stressman? And what, what did we work on in the past, just to give you a good glimpse into our world of stress. So we tried to make people relax while they are doing their stress. That's like the basic fundamental vision for the company that I started 10 years ago. And I have always been a very curious person. So I started this company out of the intent to have a company where I didn't have any limitations or boundaries, in the form of all you're a piping engineer, you're a structural engineer, you're a pressure vessel engineer. So it's, it's kind of what I can do, or I am doing a lot of different types of stress. For example, with pipe stress, it's important to understand how the pipe supports are reacting to the forces from the piping. So very often, that's like two different disciplines. Within a Stressman, that is something typically one engineer does alone, or if it's a big project, he does it with another person. But they communicate very, very closely to get all the benefits that he can have from this and that's something we're going to talk more about today. So that was my intent back then and still is for a future as wrestling grows offshore systems, well, subsea systems, actually, subsea systems. Yeah. So is that we do a lot of subsea,
Luuk Hennen 17:34
a lot of subsea, how much would you say? Sorry, how much would that be? Is that like a big chunk of your project work?
Sondre Helgesen 17:42
Yeah, I guess subsea work is like 60-70% of our work. So, 90% of our work is for the oil and gas sector, in Norway and also globally. So, most of it is subsea, then a lot of that is the top side, like on top of the platforms like drilling units, fpso, lng, yes, and so on. So, subsea is a really interesting topic. Maybe we can do another one on that, and we will, we will, yeah, exactly. So, right now, there are like 22 people in the company. So, it's grown a lot over the last few years. Still not a super big company, but it's kind of a form. So, that's very interesting, for me, at least, but maybe more interesting is that we have one member on the SB 31.3 Committee, which is one Manuel Mandus Franco. He is also the founder of the Psi Association. I'm going to mention a little bit more about that one in just a few seconds. And he is in the SME committee itself in the Yeah, in the committee itself. Yeah. So we got like, we can get feedback if you wonder about suffering. We can ask the committee as members and that's a very very big benefit for us. And there is also something called process industry practices in the US not so common over here in Europe, but we also have a committee member there as well. So that's pretty cool. And we are also representing several companies like your company look, engineering trainer, trying to push the other courses as well. And we are also a reseller for Dynaflow research group who does a lot of making a lot of nice global software. Renko pipe supports is an induction vendor and we are also working closely with the University of South southeast of Norway, which is just basically in our backyard over here. I mean,
Luuk Hennen 19:53
There are already so many topics passing by. I would love to have a discussion about induction banding and what that is. Yeah, I know Didn't know that much about it myself.
Sondre Helgesen 20:01
I always like those discussions, because they are, there are so many myths in the market about induction bands. And it's always good to have these discussions and then getting feedback directly from the people watching. I think that is super cool to do, we did it live a couple of times in Singapore. So that was a lot of very vivid discussion going back and forth. Not going into that right now. But I think I have a picture in a couple of slides where we actually burst the pipe just to prove our points. All right. And then most of as I said, most of the clients we have are from the oil and gas business. So the psi Association, which was started by one, it's an Association for pipe stress engineer. So if you're not a member, I would sign up right away is free of charge is a nonprofit organisation. And before the COVID, we had several events like, real events, where we invited people and in different cities, we gather, we got what to call it like sponsors, so it was like full dinners. What is it like? Yeah, it's global. So we have associates in different countries like Nigeria, South Africa, India, Spain, and of course, Norway. Euston wants us, then, of course, Mexico. So it's starting to form as a big global organisation, and by when the viruses come, hopefully, we can be having more of these kinds of events, you know, yeah, we invite a lot of people. And we have topics that are related to pipe stress, but sometimes also topics related to totally different things like, engineers, and how to mingle. You know, most engineers are quite introverted. So that was like one of the topics and they got really good feedback. So yeah, it's just a nice place to go and meet new people and meet common peers in the industry. All right. So what is the website, psi site is the psi association.org, it is all right down there? Just to mention, just to show our diversity and diversity is that we are going to have like one, he's going to have a speech at the 21st American LNG forum in February. And I'm just mentioning this because we managed to get a discount if somebody wants to attend. It's a live event in Houston. So he will be talking there as well.
Luuk Hennen 22:42
I will try to get him on board for one of the live streams of engineer trainer just to talk about psi and what they're doing.
Sondre Helgesen 22:52
Exactly. And he's also going to be a co-host of the pipe stress course I began around February, March. And that's the nice thing about the course : it's going to be me, one and Jonah. And the three of us have very different backgrounds. So that is something I think is going to be very interesting, because I've always been into the very small details of pipe threats in older, difficult scenarios, while they've been more on the very big scale projects, where you have 10s of 10s of engineers just working with pipe stress, for example. So it's a big diversity among engineers. Yeah, that's
Luuk Hennen 23:35
interesting. I myself, I'm also coming from like, like a very specialist company, you know, and the broader EPC perspective is, is like, somewhat different in the way they work and the way they prepare their work, etc. But we'll get to that later. Yeah.
Sondre Helgesen 23:53
Yeah. So as I said, we are global basically, we have offices in Norway, USA, and Mexico. And we also got some people working for us without our own nice office yet, but in California, in Tabasco, Nigeria, India, that's, that's really cool. Awesome. And, as they used to call it, we still call it the stress man Academy that we had over in Singapore at least once a year, sometimes twice a year, which is the same course as you mentioned as the pipe stress course. So is that even one in Singapore? Right, that was the classroom on Yeah, exactly. So I was flying into Singapore, Korea, different places in Asia, but mostly in Singapore. So we got a lot of context there. So that's really nice. Yeah. And then, for the Academy, we also know how like this, this relationship with you yet engineering trainers. So now we're basically global.
Luuk Hennen 24:54
Yeah, we're basically integrating or implementing onboarding disbursement again. Let me on to engineering trainer.com when it comes to all the online products,
Sondre Helgesen 25:05
exactly. So, so in stress man, we've been doing like 300 projects in the past 10 years, we are exactly 10 years now. So, so, and it's kind of exponential growth in the number of projects. So it can be anything from simple hand calculation to extremely complex FAA analysers. And as you asked about how much was for sub c, so 90% is oil and gas. And I guess like 70% of that is subsea awesome, into too much of the details there. Make sure it is usually nicer. So we've been working on heavy lifts of ships, subsea analysis, as you already mentioned, where we look at the entire system as well. And we're going to talk more about that in a few seconds. We do CFD, for example. Yeah. Detailed unlicensed subsea manifolds, trailing racers. So I'm just showing this just to give a little bit of difference that you can see that they are doing different stuff. It's not only piping, you know, yeah. So here is the pipe that reverses that 1300 bar is a duplex pipe at those induction bends. And the extrados is thinner than the burst area over here. So that was a very, very, very quick version of it. And just the other thing is that Oh, but it's not symmetrical. It should be symmetrical right here, the only force, the only load here is the pressure. So but it was due to the mill, the mill tolerance was more on this side than then over here. So that's why it was yielding over here first.
Luuk Hennen 26:42
Yeah. And this was a band that was an induction bandit, or is it?
Sondre Helgesen 26:46
Yeah, it was hot. Induction bent. As you can see here, this has a little bit different colour, because he's been heating up, bent, and cooled down. Alright. So that's something that we use all the time on because we use these pens for subsea applications. Alright. Yeah. I think I will skip quickly through them. It's just some pictures of some pipe stress models. So it's making sense there are pipe stress people here, they like to see some models. This one we'll talk more about. Yeah, this one too. So water hammer effects. Do you have a course on that? Luuk?
Luuk Hennen 27:31
Yeah, we have a free one, actually. So yeah, remind everybody to check it out? Yeah, it's like one and a half hours discussing the concepts of water hammer. Yeah.
Sondre Helgesen 27:40
Yeah. So this was a water hammer problem where they will be seeing some support sliding off the beams that were resting on because of the water hammer effects. So the task of like, how slowly do they need to close down the valve? Not again, right? That kick-in line? All right. That's the manifold. It looks simple. But we use three and a half 1000 hours on this one. But it looks like from concept to the final product. And we did the FDA of every single component here because it was just them. Everything is custom. Okay, is 900 bar the same pressure? Wow, what thickness are we talking about in such pipes are 4050 millimetres of super duplex, okay, and the biggest inner diameter of diameter, it's the biggest, almost 12 inches in diameter is a custom pipe as well. It's not like a typical nominal pipe size pipe. So the idea was, you know, the diameter was 12 inches on parts of it and then 10 inches on the smaller part over here, hence hence
Luuk Hennen 28:45
the FBA because I mean, it's not always thin piping, then I'm sorry, hence the FBA part, the finite element analysis because it's not always, you know, considered as thin piping.
Sondre Helgesen 29:00
So we had to do every single component here that was, as I said, detailed and calculated. That's also a very interesting topic that you're touching on in the course, not in detail, but just giving a brief overview of some other types of subsea manifolds. And people are wondering why this pipe is so long to have a lot of flexibility. Because of this green area over here, it's very connected to the next subsea module. And when you mounted subsea it never got to fit perfectly so you might have to lift it 100 millimetres and push it sideways, another 50. So it needs a lot of flexibility to hook it up. Yeah, that's, that's why you have the flex loops going out like this.
Luuk Hennen 29:47
Yeah, I once saw those, and they were called elephant ears. People call them elephant ears. I liked that there.
Sondre Helgesen 29:56
Yeah, that's nice terminology. Yeah. Detailed calculation of components, as I mentioned, calculating the stress intensification factors and so on, do ease the number of analyses in the system. Like our background, it took a little bit more time since you were asking questions. So that is our background. Can you still see my screen? Oh, yeah. Oh, the topic of today, as we talked about before we went live, is going to talk a little bit about pipe supports, and how, how the different loads are kind of against each other, working against each other? What happens when you put a gap in a system and, and friction and the stiffness of the structural steel?
Luuk Hennen 31:03
Alright, I see lots of primary loads, secondary, I think that is a very interesting topic. Right, primary versus secondary? And then also, you know, the question we get asked a lot is like, why do you instead of, you know, adding, like a load case that considers the temperature? Why do you subtract? Brian, the sustained load case from the operating load case, etc. So, I would love to dig into that. Yeah.
Sondre Helgesen 31:32
Yes. So that's what we're gonna talk about. Now. As you say, the primary loads, they want low flexibility. Let's say if you have a very long flexible line, and you have a big valve or some mass on it, it will collapse under its own weight. So you need to start supporting it. But the second you start supporting it, it will counteract the turmoil growth of the pipe. So if it's a hot pipe, it wants to expand in different directions, all depending on the layout of the pipe. So that is going to be acting against the usually against the pipe support that you add into the system.
Luuk Hennen 32:18
Yeah, it's like a balance, like when it comes to flexibility, you want to keep everything as flexible as possible, so that it can expand, etc. But when it comes to vibrations and dynamic effects, you basically want to put it all into concrete, you know, it can vibrate, and there's a salary somewhere when it comes to supporting.
Sondre Helgesen 32:41
Exactly, that's a good way of putting it. So because you don't usually, you don't want low natural frequency, you want them as high as possible. It depends, of course, a bit on your equipment and so on. But, but in a case, I began to talk about, now there was some very strong triplex pumps that are used for the drilling systems and they have a low RPM, I think they have like 120 strokes per minute, that gives them a What do you call it a pulsation frequency, the lowest one is six hertz, because they have three pistons in them. So we're going to talk more about that. And the book was actually found in the case that they're looking at. It was found in that case. So we needed to add more support, but then we're getting to high loss loads, for example, or high, too high secondary stresses. So yeah, and also, I think if you just start with that topic, it is a sorry, not topic, but the case because it's easier when you have something to point to. So as I said, this is a drilling system on an offshore drilling rig. There we got involved because you can see my mouse pointer, right. Yeah, it's moving around over here. So in this area where I'm trying to kind of highlight it was a lot of vibrations. I will show some pictures of that. But over here, it was all the vibration that was why they contacted us in the first place. And we started digging into this problem. And this is a high-pressure mud system. It is quite a heavy roll thickness on the pipes as well, and is a very stiff, very stiff system. So the pressure here is like 690 bars from sun line lines and 1035 bars on different lines. Temperatures the same are 121 degrees Celsius and 177 degrees Celsius. But what is most interesting is not too extreme temperature ranges here but what is interesting here is the ball thickness as you can see it's five-inch line with 1.2-inch roll thickness. There's almost no opening in the middle of it. So now, of course, there is some stuff in the lower area, but still, it's really thick old pipes. So these pipes are very, very stiff and also the flow is mud.
Luuk Hennen 35:09
So that is like a combination of weight and solids. But is it like a steady stream or like more like a two-phase flow,
Sondre Helgesen 35:21
you can have a little bit of two-phase flow during startup and shutdown. But in this case it was the pulsations out of the mud pumps that were making that acceleration force. Before the oscillation, the force wasn't too high. So so. So then it became this Yeah, and also that as you can see that the bands are a bit longer radius, I think it is 3d bands, but they are double back then. So they had double thickness in the band to erosion problems because it's eroding fast, then you have these solids in the flow. So that makes it even stiffer than usual. And then we have the flexibility versus natural frequency battle is like we need flexibility. But at the same time, you need as high stiffness as possible. So the initial problem, as I said, was extensive aberrations, secondary problems that occurred after we started playing around with the systems. And there were also some initial problems with the initial analysers that didn't perform. So we had to kind of redo everything.
Luuk Hennen 36:35
But this was a build system. Right? It was ready.
Sondre Helgesen 36:38
Yeah, that's a very good point here. That's a very good point. This is a build system. They called us after everything was built, pressure tested, ready to go, and shipped out. So it was crucial for them. Not that we didn't start changing the pipe routing as well. Yeah, exactly. Because starting to cut open these pipes again means that you need to do all those things, again, that the testing, so and it will be very, very expensive to go in there and say, Oh, I just need the expansion loop over here, for example. Yeah, that was something we should try to avoid, I mean, we managed to have the pipe routing the same, we didn't change the pipe, we had to change some of the supports. So when we started looking into it, he also found very high lows, at least compared to what was specified by the vendors of the equipment. All right. So when we did this very typical workflow, because as I said, these pipes are very stiff. And when we did the initial screening, where we assumed that the pipe supports were, like, rigid, like Normally, you know, you'd add the direction the pipe support is acting. We had frequencies that didn't show us any major problems. But then we started looking into it, and we see that the supports are quite slender. If you see we destroy them upright, structured structure, yeah, the structure of the pipes, but not the clamp of the pipe supports itself with the structure that holds the support. Yeah. So you can see, for example, this one here, it was two meters tall. So what are we looking at? These are the structures. Yeah, these are the structures that are in the model, then in software called SAP 2000. Just structural software like statpro and Sachs. So we remodelled them in there and remodelled them closer together. Because it doesn't really matter where they are in space, because they are taking out the stiffness of the supports. And we are adding the loads from the analysis to it. So far, as you can see, some of them are very, very slender. So they are that means that they're very soft.
Luuk Hennen 38:58
Yeah, actually, you know, since it's such a stiff system.
Sondre Helgesen 39:03
So we were anyway going to calculate all the pipe supports in the project. So we did that first and calculated the stiffness of all of them. And then we took that stiffness into Sisa. You can also use the structural modeller in Caesar. To
Luuk Hennen 39:20
Yeah, I was gonna ask, like, why did you choose like, do it like this? Instead of modelling the actual frame into the pipe stress model?
Sondre Helgesen 39:30
Maybe we're gonna do code checking of each member afterward, there are some code checking for up to four members, I think. But it's According to the American standards. We were going to do it in accordance with the European, so it was recorded automatically. Code checked in step 2000, in accordance with euro code. And in the North Sea. For example, we have something called Norsok which is that extra set of rules that is applicable to everything we do. So it might be, for example, when its structural steel, it might be a higher material factor than the regular ones used for buildings onshore, for example. So it might be more additional safety factors, it might be setting up the loads. And that is all founded in North sock regulations.
Luuk Hennen 40:25
That is a Norwegian code, right for Norwegian acceleration.
Sondre Helgesen 40:28
Code. Yeah, for the offshore business here in Norway. And I see several companies around the globe are actually adapting also some of those codes into there. They are the signs. Alright. So we were calculating each of the supports getting the stiffness. This ran a simple model and licensed CCT to check the frequencies. And it went a little bit down. But still, it shouldn't be a problem with regards to the vibration that they saw in the system. So we continued, and we did the boss pulse calculation, you know, Boss, boss. Yeah, definitely. Pretty good. So, yeah,
Luuk Hennen 41:13
I mean, that's just to give some clarification as Bill's is a software package provided by dynaflow research group that allows engineers to do pulsation studies in the piping system. It's actually pretty neat. You model the compressor, and then you can calculate the Acoustic Resonance in the piping system. So yeah, those are very interesting calculations. Yeah.
Sondre Helgesen 41:39
Yeah. So we did that. And it did a harmonic analysis, and he said, We afterward just to see the resonance. And still, we couldn't see much. Okay, so yeah, here, here's a picture from boss Paul's. The model that he took from Caesar to be inserted into boss posts. This is just a small area of the model, but it was in this area where we had a problem. Yeah. So we got the data from boss Paul's. And basically, what these lows are saying here, peak to peak force, that's the unbalanced force in the system. So in this case, we had 9000 Newtons as the peak to peak force. But we don't need much force if you hit the natural frequency. So that was what was happening here. It was, it was shaking quite a lot. I
Luuk Hennen 42:29
mean, maybe interesting to elaborate on this a little bit more to make sure that people understand what they are seeing, basically, what this shows is like the piping system, and then what basils do is you have a compressor that gives little pressure fluctuations instead of
Sondre Helgesen 42:48
right, it's a pump. Yeah, the mud pump is giving pressure fluctuations or pressure pulsations in the system, and those travellers if they resonate, exactly, but under travel with the speed of sound through the system. So the speed of sound of the content and the stiffness of the system. And sorry, and they're longer usually between the bands, the higher than force, it'll be very, very close between the bands, then the signal hasn't moved that much. It doesn't take much time to move from one to the other then the loads will be lower. So this is basically the software is what it does, that was our main purpose here for us was to get the loads out of the system. The software can do a lot of other stuff as well. That was like what we really needed from
Luuk Hennen 43:47
the analysers. So we got one question, Sondre, from math. I think that's an interesting one to know. I mean, just to make sure there will be no spring hangers in the system, right? Because it's
Sondre Helgesen 43:59
very good question. Perfect. I actually had it on my notebook mentioned spring hangers. Yeah, it was no spring hangers. That's there were non-spring hangers in this system. But I wanted to mention the spring hangers, since he asked I think is a good time to mention its spring hangers typically have a very, very low stiffness at least compared with regular supports and the piping system itself. So so my experience is that adding a spring hanger to the calculation doesn't really change the dynamical response of the system.
Luuk Hennen 44:40
Because the stakes are so much stiffer.
Sondre Helgesen 44:43
Yeah, so if you had, for example, a system that has a lot of spring hackers, can you have a dynamic load on that? That typically is a problem and they, for example in the North Sea for offshore projects they are saying avoid spring hangers at all costs and To this day, I haven't seen Yeah, I've seen a few spring hangers on Val heads. That's true. But other than that, I haven't really seen spring hangers use that much offshore because they don't want these vibrational problems. I can't imagine you need to find a workaround
Luuk Hennen 45:16
would also, I can imagine corrosion would also, you know, being offshore. Since it's a mechanical part, you know, that might move. I don't know, I would, I understand. Yeah, I understand their perspective.
Sondre Helgesen 45:33
Right. So then, as I said, we tried to do all of these things. And still, it didn't vibrate, mostly everything looked fine in the analysers. But when you looked at it on-site, it was vibrating with half a diameter. And as I said, these pipes are very stiff. And I mean, the operation is quite a lot. So what we started to do was to play the what-if game . What if that support is not there? What would happen? What if the support is not there? What will happen? Because it was clearly something we couldn't understand the system, and we didn't have access to the system itself. It was far away. So it's
Luuk Hennen 46:14
like no, like mitigation measures, but like, understanding like, what is going on in the field?
Sondre Helgesen 46:21
Yeah, exactly. Because I always like to have a benchmark model, especially with dynamic problems to be able to generate the vibration in your analyses, then you know that you have a good benchmark model. So what we ended up with was that before that two supports over here, it wasn't welded, it was saying in the drawings that they were supposed to be welded. But when we looked at them, when they asked the guys on a vacation yard to go out and take a look, it turned out the support was there, but they weren't welded to the structure. It was just acting as a support. Yeah, exactly. There's a sliding back and forth. It didn't, it didn't stop that motion that they were supposed to be stopping. So we found that okay, the license was showing roughly half a day diameter of vibration, at around those frequencies, but they were never observing it, and they were testing the system. So that gave us a very good benchmark of the system. Now we know that you have a system that he can start to tackle, you know, to start to, to work on.
Luuk Hennen 47:31
So the customer dates, like vibration measurements or anything like that, know the idea sent out there with their phones already. Yeah, that's like an estimation of the displacements and stuff like that.
Sondre Helgesen 47:46
Yeah, exactly. So the thing was to get rid of those vibrations. So, it was a very unscientific way of doing it. But it was a rough estimate, at least Yeah, we have done the same with subsea piping as well, the problem some and sometimes you can put it like as if you take it into one of the movie editors, you can start to track pixels. Yeah. And if you know any relationship like the diameter, you know exactly how big the diamond race and you can know that one pixel equals X number of a millimetre, you know, I've been tracking their vibrations up and down. And that's really interesting, but for subsea that is sometimes impossible because you got to fish for the fish swimming in between the camera and the vibrations. They do make recordings, they do go with a camera. Yeah. So it is really nice to see a lot of codfish here in Norway, so it's not that easy to see it all the time. So that was like the initial problem. Why is it vibrating down license showed that it shouldn't be vibrating? He figured out okay, it's in that area, that it has some problems, and also several other supports had quite a lot of gaps in them. Due to that, the first analyser showed that it would have a lot of thermal expansion stresses in those areas. So they added gaps and we're going to talk about gaps soon. But that also made it very article it's in English. Easy to shake. rattling
Luuk Hennen 49:28
we got a question like from, from Canada up? I think that's a question. Interesting question as well. I mean, if you include the structural parts into Caesar or any Bozrah software, it would typically include that's why you would that's why you do it in the first place include the stiffness of the structures that the whole that's the whole reason for doing and then you connect the piping with the structures using a C note you know, using the direction There's a freedom that you want to, you know, connect both. Yes. And then you put anchors into structures where they are fixed. So that's typically how we do it. But in your case, you used the stiffness that you got from older software, structural calculator software, you added them into the pipe support, right? Yes. All right. Okay.
Sondre Helgesen 50:22
That is true. So we were extracting, as I said, the reason why we did it in our different software's was to get the code check of each of the beam elements easily.
Yes. And, and then, we started looking into the moles that we got. And there were several companies who worked on this system, and they chopped it up. For example, here, if you see my mouse pointer, again, it was just an anchor there. And I asked them, okay, is there an anchor? No, but that's kind of where it's penetration for the decks or for the ball. So that's our end of the scope. That's our scope, you know, it's up to here. Yeah. And then the other company who modelled it, they continue to model up to this area over here. So there's like, both companies for the anchor on it. And I'm like you, but you can't do that, especially when you're looking at operations, for example, you need the entire picture of it, you need to go from one end to the other end. Or, or you just need to agree, um, let's have an anchor on here. And that's a good, good clean cut between the two analyses,
Luuk Hennen 51:37
but it was like a crossing through, like a deck or something you mentioned, was it a fixed point? Was it respect? No,
Sondre Helgesen 51:43
no, no, it wasn't a fixed point at all. It wasn't at all so we removed that. And that also changed their behaviour, quite a lot of the system, of course, and then they modelled everything into one model. Because we started to see these kinds of assumptions, then they made incorrect values on the nozzles. So yeah, this is like high pressure. Oh, sorry, choking kills manifolds. Alright. And this actually belongs to the different projects where the task was to calculate the manifold itself. But it's very detailed. And you can see most of them with all the green stuff here that's like rigid joints. So all the rigid joints are actually with some stiffness in them because it's not 100%, stiff, these valves. So so it's a little
Luuk Hennen 52:43
a bit longer. So if I understand it correctly, you have like a Caesar model, and you have a like, visual of the actual system combined. Yes. And yes, that is very correct. There are a lot of vowels in there. And all those vowels are represented by the green widgets. Exactly. Okay.
Sondre Helgesen 53:04
So this is basically what we can see here, for example, there is a more simplified version of it if you see my mouse pointer and a little bit to the left. So yeah, you can see this part of areas Actually, this one in detail, if you're calculating every single detail for each leak at each flange, and so on. So if that is in the analysis, yeah, here we go. This is the manifold connections, you can see that the piping is coming in here to different nozzles of that equipment. And yeah, sorry, I see some of the flashes have been marked as valves. So they're supposed to be three inches. But when they enter here, and you can see, it looks like there is an anchor here, but it's not really it's just a C note, as you just mentioned earlier, we will talk more about see notes, later on, it's just to be able to extract the loads on the nozzles, these areas is much simpler than going into the element loads, you can just go to the restraint loads, and take out the loads. Exactly. So what is happening here is that, as I said, the temperature range is on some of the pipes, 121 degrees Celsius, on some other pipes, 177 degrees Celsius, you know, 50 250 Fahrenheit. And the thing is that and then you can also see these red ones here that are actual supports, but that supports that we have calculated a stiffness off as well. But what we often see is that people tend to set an anchor where I have my mouse pointer on the vertical stretch here. Vertical stretch here as well. And here and here. We tend to have anchors there. And I've been asking people, why do they do that? And then like, no, they want to shield the manifold from the external loads, all right. But as I just said, the sign temperature here, it's up to 177 degrees Celsius. So this manifold, it will expand, you know, the support. So if you try to hold it here, you get very, very high loads on these nozzles. And it's not the external piping, that is the problem, then it is the expansion in the manifold. But a lot of times I see that people are adding an anchor here and they stop the analysis here. So they do pipe up to here and they stop. Same here, here, and here. But don't then you don't get expansion in your manifold. And that goes for all kinds of equipment as you know as well as, for example, if you have a tank or a pressure vessel, that is hot, it will be expanding, maybe vertically, it is a vertical vessel, then it will be expanding vertically and gradually. And you need to take that into account in your calculation. The same thing goes for these manifolds, as you see here. It's all made of steel, it will all expand and get the right terminal loads on these flinches here.
Luuk Hennen 56:23
I have an interesting question from Brandon. Thanks, Brandon, for taking part in the discussion. He's asking about expansion joints, like, what is the advantage of using pipe anchors versus expansion joints for this kind of thermal expansion? What's your take on that? Yeah,
Sondre Helgesen 56:43
expansion joints will be working, but this is 690 Bar 10,000 psi. So it's difficult to find any expansion joints that actually work with this application. And
Luuk Hennen 56:53
What is commonly used in offshore expansion joints?
Sondre Helgesen 56:58
Now, that's also something we really try to avoid. Then we would rather get a good pipe routing, then using the expansion joints, right. But as he does that, I also see that the expansion joints get better and better and better. So like metallics expansion joints, I spoke with some people that are producing that. And based on their tests, they become really good. So it might also be a little bit like old myths in the market as well about the benefits and disadvantages of using expansion joints.
Luuk Hennen 57:38
I've seen some pretty corroded ones, you know, in like, pretty old system. So I'm a little bit, but I could understand the hesitation. Let me put it that way for an offshore system with all the corrosion proneness. But
Sondre Helgesen 57:58
yes, so. So as I said earlier. The problem here was to find, like the balancing point, between high stiffness and enough flexibility. Yeah, and, and what we ended up doing was to change, we looked at what we had that was already built. And we started looking at each one of the supports, can we remove support to add flexibility to the system? Or can we change the support functions to kind of get a little bit more flexibility, but at the same time retain some of the stiffness? Yeah. So that was the main challenge of this project here. And what I usually do when I'm doing especially new projects, in this case, we were very locked in on, we couldn't change the routing. They said to us "if you need to add support, please as few as possible. If you want to remove supports, No problem, that's easy, it was all bolted. So you can just take them away again." But what I try to do every time when I start a new project, well, first of all, I shut off my computer, and I sit down, I print out the ISOs first before I shut it down and then I'm looking at the system as a system and thinking what will be the main loads, how will they act where How will the temperature expansion look like? How will acceleration affect the system and so on. And I kind of try to draw the lines by myself on paper because that kind of Prime's the brain that is good common practice. I mean, I didn't always do that I have to admit. Yeah, so somebody had done that. Sometimes at the beginning of a project. I don't set up all the load cases at once because that's a lot of information to dig through. I set up, for example, just pure thermal expansion, pure vents. For example, Just to see what would happen, or how does it want to move in the model? Yeah. And there you have not much thermal expansion, vertical, very don't have so much movement of the thermal expansion. That could be a good play, point-to-place support. Yeah, yeah. So I'm always trying to look at it from a very simple perspective at first. And then when I start to feel that I know the system, I know how it's going to react to the different types of loads. And I built all the load cases. But in the beginning typically I might just add, for example, if I know there is a blast load in the system, just add the blast load, see what happens. And then, and then accelerations, for example, just see how much stress did that yield. And, and it might not be the real values that I get out. But still, it's a way to get to know your system, especially
Luuk Hennen 1:01:00
those ones that you anticipate to be the critical ones, like blast molding, and,
Sondre Helgesen 1:01:07
exactly, so. So that's, and for example, then you can see, that's where you have the most movement, you're the last load, if you put support exactly at that point, that is probably going to be the best point to support for the last load, and then you need to take a look at the thermal expansion deflection, and maybe there's a lot of thermal disc displacement in the same area, then you might have a problem with your thermal expansion stress. Yeah. So it's like finding this.
Luuk Hennen 1:01:42
So you do this, like you do this before, like, what I always used to do is take a piece of paper and just start defining the load cases. You know, but it's interesting to hear that you start with, you know, about, you know, having a look at the loads, and then the possible, you know, responses of the system, the displacements. And through that, you know, reasoning, go to setting up the load cases.
Sondre Helgesen 1:02:06
Yeah, and probably the load cases, if I set it up afterward before it would be the same. But still, that's just my way of thinking. And as you saying, There are several ways to get to this, the answer here, but I always believed very strongly in really thinking through the problem before jumping all over it, you know, it's, it doesn't take that much time either just running a few cases quickly, to see, especially when you've done it a few times, you see that, okay, that happens, that happens. And you already predicted it would happen, but then you get some numbers that confirms that it may be the stresses are super low due to the wave acceleration, for example, then. And that's not going to be any of your concern, you know, we don't need to add a lot of guide supports, if it's not that much movement sideways, for example. So that's just the way I'm doing it. And I will try to take out some pictures and I can put them in the LinkedIn forum where we have this discussion. There's a shitload more of that. So the lessons learned from this system was that flexibility is not always but it's very often fighting against natural frequency, you want to have a high natural frequency, but that means low flexibility and vice versa.
Luuk Hennen 1:03:34
What were the natural frequencies for this system, like this system
Sondre Helgesen 1:03:38
had a natural frequency of in the beginning, and we started looking at it 6.9 hertz, alright, so and load them which, yeah, and we managed to get it up to around nine hertz as the lowest one. And then what we told the owner of this system, then it was like, okay, you could probably push it up by adding more supports to it. But that would be very costly for them, it was easy for him just to run another test on it and see that Okay, now the vibration that you saw earlier on, it's gone. So, yeah, and it was like we had to include a structural stiffness to get the right response of the system. So we calculate the structural stiffness of each of the pipe supports or as you said, Look, we can use a structural steel modeller in situ or different software like triflex for example, I know there we are often modelling the structural steel directly in the model and connecting it through C nodes or connection, no sorry, release elements like cold air. So there are different ways of doing it. And then, don't add fictional anchors, people call them fictional anchors. I feel it's just bogus because I have seen it in several projects. Okay, this box is our scope of work outside that we don't care about. And then on the boundary, several people put their fictional anger.
Luuk Hennen 1:05:14
Okay, so anchors that are only in the model and
Sondre Helgesen 1:05:18
have nothing to do with model building people find that they say okay, it's very little load on the anchor. But how do I know that the other people fought about it as well, you know, so I have seen some very bad mistakes there? It doesn't make sense. And also it's even though you see it's low load solder, for example, you cannot calculate the correct natural frequency of the system, especially if the area you're looking for is close to that fictional anchor.
Luuk Hennen 1:05:44
Yeah, I would say for especially for dynamic analysis, you know, such non-existing anchors, putting them in your model is, like, really bad practice, I mean, but even for static analysis, you know, you have to include some type of continuation and influence of parts outside your scope, see how they interact with your sections. But especially for dynamics, dynamic analysis, such anchors will change everything.
Sondre Helgesen 1:06:14
Yeah. And then always confirm the boundaries. When we see this, not only on this project, I also got one phone call one time, and we had one phone call when we had a fpso with a 30-inch line that was moving. And the guy on the other end said he's moving 30 centimetres, like tourists centimetres, like 300 millimetres. Yeah, 24-inch line. I was like, I cannot do that. That's, that's dangerous. So they had shut it down, of course. And I looked into our model about three to four millimetres with rough slug flow that was driving this motion. And, and I was checking it out, I was adjusting the loads and the maximum I could get there was like maybe three or four millimetres of displacement in my model. And then I told him to go out there and take pictures of each of all of the sports and most of the supports for distress supports, they weren't the anchors weren't there to guide sources there. So then the line was moving quite a lot. But it was very interesting. It was the same thing. And we see it's a bit sometimes when we make the pipe stress calculation, the handle down to the structural, sorry, not structural will be handed over to Yeah, the structural pipe support guys. And they're supposed to put it in there. And they even draw the correct ones so the drawings are correct, but it's not executed correctly. So that's always very important for firm boundaries.
Luuk Hennen 1:07:43
Yeah. I mean, I've done a few inspections, like whenever, you know, the situation allowed it, there were a lot of practicalities in there. But you know, it's really great to know, analyse the system, and then seeing it straight afterward. And you know, you work so many hours on it, you just walk around her and see, you know, hey, this is all different than what I intended and this is correct. But I mean, it can save you a lot of problems.
Sondre Helgesen 1:08:15
Yeah. The only problem is that usually when we do the analysis, it's being produced somewhere far away. Exactly. So it's difficult to go out on the field and take a look. But having people at least take some pictures or and they should do this it's part of the as-built so I don't know, to understand why sometimes happening but I think it's it's so so important to just know that even had a project where the people mounting the pipes, they felt like oh, it needs a pipe support over here. It needs pipe support over here. So adding pipe supports killing our flexibility. So there is a lot of reasoning usually behind the pipe stress analysers.
Luuk Hennen 1:08:55
Yeah, I got one interesting question from Ash. First of all, thanks, Ash for joining the discussions like in this system, Sondre you took a lot of effort to have a look at the model or to support their stiffnesses, etc. But you don't always do that right. I mean, no question. They are standardised like just the pipes, the boat shoes. The sports are standardised. Yeah, what is your take on that?
Sondre Helgesen 1:09:29
Yeah. Now by all means we don't do it this detailed every single time we do a pipe stress analysis, he wouldn't get anything done. But in special cases like when you have a very flexible pipe that is very stiff then it's natural to take at least a look at the structural drawings of the pipe support structures. If they look very slender, put them into the model, see what happens. If they are really beefy and Strong, no problem, they're probably strong enough. I don't have a rule of thumb on this. But let's say if you're supporting a two-inch pipe with low wall thickness, it doesn't have much stiffness. And you connect that to a hollow section, for example, it's probably going to be totally fine. And but for the bigger pipe, the stronger it is going to be. It was like that project. I mentioned. When I was showing the portfolio earlier at the very high pressure one, in that one, the piping was stronger than the support structure around it. Oh, wow. Yeah. Because the beams were like really strong beams. But in certain directions, in the weak axis of the beams. The piping was taking most of the load, not the structure below it. But that was how we designed it anyway. But in that case, it was so important to get the structural stiffness of the main structure.
Luuk Hennen 1:10:59
Yeah. I mean, I have a couple of questions. It might be worth just running by, we have a docking over like we're one hour in the session. So yeah, I see that. I mean, time flies, but we'll just see if we can touch about the topics or how to progress. Lets, let's have a few discuss a few of these questions. So one notification that that code Corrado sorry gave, which is an interesting statement, I think, is to include support settlement, if needed. And I mean, I, as I understand it, you know, if support moves, separate from thermal expansion or any movement of your pipe itself, you include those as a, like displacement on a C note on that support. I mean, that's a good point. I don't think it's valid for this case, as as you know, it's all offshore, there's no settlement of grounds or,
Sondre Helgesen 1:12:00
yeah, it's actually a settlement of the ground on the offshore all the time. Because of the offer structure, they're a bit flexible. Okay, but then
Luuk Hennen 1:12:10
displays, right, not one support.
Sondre Helgesen 1:12:13
So in this case that we tested out, it wasn't like the driving force, so we didn't pay much attention to it. But in order, let's say if you have a ship, a long, longship, you have a pipeline on top of that ship that is going to be like your harmonica. Yeah. Yeah. Yeah. It's an accordion, the accordion? It's a force
Luuk Hennen 1:12:37
displacement from the ship onto the pipe system.
Sondre Helgesen 1:12:41
Hmm. That's right. So that's a very interesting case. We don't have several analyses like that. And you need to calculate the relative displacement between each of the pipe supports in both horizontal and vertical directions. Yeah,
Luuk Hennen 1:12:59
yeah. All right. So one other question, which is a different question, but I think it's interesting. One from Ireland. Thanks, Alan, for asking, how important is it for a stress engineer to know the design of pipe supports? I mean, typically, pipe stress engineers, they use standards, right, which have allowable limits level loads on the pipe? support?
Sondre Helgesen 1:13:26
Yeah, yeah. But that's for shoes, the pipe sports shoes itself. So they have like this, these design guidelines or design basis, or whatever they call it. specifications that as you say, they can go in there, you can pick out shoes that are suitable for different temperature ranges, many of them have a level load stated on them. So that's one thing. That's the simple part of it. But in this case, you're not talking about the structure that connects to the sheet. With a shoe, it's like the link between the structure
Luuk Hennen 1:14:02
and the shoe is not like the limiting part. It was the structure itself.
Sondre Helgesen 1:14:11
It can be let's say you use a u-bolt, for example. Yeah, and you have a lot of side sideways loads on the U bolt, and you both might be failing a long time before the structural steel that it's connected to fails. I
Luuk Hennen 1:14:26
was actually educated in this field, not being allowed to use u boats. So I don't have any experience at U boats. Although other than that my seniors would tell me to do it over.
Sondre Helgesen 1:14:42
Yeah, so I've been working a lot with u boats actually for the offshore industry, but they are usually very weak in the horizontal direction. Yeah.
Luuk Hennen 1:14:51
Yeah, exactly. So yeah, that's another question. We got this about the friction in this model. So I mean it's a heavy pipe? How did you include that?
Sondre Helgesen 1:15:05
They are in this model the friction was in. So we actually added it as it's this kind of Teflon slider on it. So it's all point one I think we used in the model. But it didn't matter that much, we were checking it out. So we were having some international problems due to that. But it's not the weight of the system. It's such a fickle pipe. So it cannot carry itself. And the weight compared with the expansion loads was fairly small. And of course, that also, again, raised friction, but we tested it and without friction on several systems, and it didn't, didn't give us much different results. All right,
Luuk Hennen 1:15:51
I have experienced several projects in which, you, you, you know, you had the support structure supporting arrangements correctly, you know, it took some iterations, and but then the mechanical eigenfrequencies of a system were still not matching with what was seen in the field. And then and then by looking at the friction in several of the key supports, you know, you could really model the reality into your system, it's a little bit different, you know, you have to be careful, of course, do not over model things. And exactly, not being able to generalise your conclusions. But friction can be important for those dynamics I
Sondre Helgesen 1:16:38
yes, but it's very difficult to do the dynamics and frictional costs, the natural frequency that you need is linear. What do you call it, the stiffness matrix? Yeah. So when you add friction, which is a non-linear load, it kind of messes it up. So, then you don't have a linear system anymore, saying that gap says, Well, you need to make a decision. Is the gap closed or open? When do you calculate the natural frequency? Yeah, I've worked around that to kind of run a time-domain that analyses Cesar to counter it. But other software like answers, for example, can run time-domain analysers. So then you will get the movement of the pipe until it touches the gap, the gap closes, for example, then it changes to behaviour and so forth. So that it's possible to model but it takes all the time to actually set it up.
Luuk Hennen 1:17:33
Yeah. I have two more questions on that, that really get my three more questions. First of all, Jamie's asking, thanks for asking, what was the solution in this in this case, so you know, you had this vibration,
Sondre Helgesen 1:17:54
Maybe I didn't explain it well enough. Sorry. So the solution to the vibration, which was the main problem over in this area, where I'm pointing right now, was basically to put those two sports back in place, and it changed. Yeah. And we changed the support types on the lower part of the piping because they had five, six millimetres of gaps. So we told them, okay, use a different type of pipe clamp on those that are kind of holding the pipe, it's not gaps in there, it is just clamped around it and holds it still. So we changed the supports on the bottom part here and we've gotten to the hell these ones as they were supposed to be. That was like the solution over here. And over here, we received a lot of piping, we were struggling with very high loads on the nozzles there compared to what the allowable loads were. So in that case, we did, we changed like some of the support types. For example, it's a bit difficult to see on-screen, probably this is just a rest hold on support over here. We didn't want to have any sideways. It was a guide. And we said okay if we need to have enough stiffness of the pipe, but you can remove the sideways stoppers and we made them. We made some sketches for them to do how to make that and it did actually work. That was changed over here. We removed several of the supports in this area just to add more flexibility and still keep it still the natural frequencies were high enough and it didn't experience any problems after running it. And also we did FDA of hair you can see is this is a little bit coarser one but we did FDA of the API flashes on the connection endpoints All right, because you got API six AF two, that's a technical document technical report from API, where they did FDA have a lot of flinches but their boundary conditions are quite conservative. So, we model the entire flange pair, as you can see down here with the pre-tensioning everything in place that the gasket you cannot see the gasket. Sorry to interrupt, it's
Luuk Hennen 1:20:27
on the Y Ave, I mean, you have this equivalent pressure rule there, the Taylor forge methods, those kinds of calculations, is pretty detailed calculations for flanges, like where the loads like way exceeding the the the results from the other methods.
Sondre Helgesen 1:20:51
Yeah, it was. So the first thing we did was to kind of mimic the original method. And they got the same answers as what APA got for their FDA. As I said, I always like to benchmark what I'm doing. So let me try to mimic what they were writing in their report. And we got almost exactly the same result if we also could get by by sophisticated hand calculations, but the thing is that we wanted to see the pressure between the ring type joints, gaskets, the metal gaskets, and, and the flames itself so that we could ensure that it didn't leak in the end, all right. So then we did it like this, we get all we try to model it as conservative as possible the gasket because, in the API document, the gasket is not modelled. It's just saying that the gasket is kind of a boundary condition. So when you have liftoff on one side of the gasket, you have compromised your integrity of the flames because then you will have leakage. So we weren't that worried about the stresses in the system. Even we were worried about leakage because according to the API if you go into this standard, there are a lot of graphs, it's very nicely done as there are a lot of graphs there. So you can see if you had that bending moment, that internal pressure, you can have no sorry, if you have that kind of pressure, you can go and see how many bending moments Can I have on that flame to get into the axial tension. But the axial tension doesn't weigh that much role in this, or at least in this system. But it was like this, you go in there you find it. And as I was mentioning, it's a conservative method to use and it works totally fine. But we saw that we could get five times the allowable bending moment by doing these analyses. Yeah. All right. So that was another workaround. And, yeah, okay. So
Luuk Hennen 1:22:56
I mean, we got one question, which is more of a general question is how to reduce those loads on? Well, and also how to reduce loads on muscles. I mean, I heard you saying a few options, like adding flexibility. And you know, having a really close look at a sporting arrangement to change the loads. I also, I mean, if flanges are limiting, you can go into real detail by analysing the flanges as you did with Yeah, that's like the last resort, only the flange is limiting, not not like the nozzle load itself. One thing I always also experienced with nozzle loads is to analyse the equipment. Well, it depends a little bit on what type of equipment you have for pumps, it's way more difficult. But for cylindrical vessels, you could do like an MVA of the vessel. And typically the allowable loads that you get from an MVA might be higher than the values you get from a vendor. But especially if you include the actual loads over your five stress model into the MVA, then you see that, you know, there's it's way less conservative than any of the assumptions made to you know, to get the allowable loads as fixed values into the Parsha system. So a VA could definitely help as well. But yeah, it's quite a general question. And I think that's also the most detail we could get.
Sondre Helgesen 1:24:26
And just a little side note to what you just said, It's when I'm looking at if I'm struggling with the operational loads on equipment, because that's what you're tracking, basically, you take operational loads, you check the equipment, that it can sustain those loads. But it's important to understand the origin of the loads. Yeah. So what I very often do is I take I in Caesar tree, this is the way I'm doing it, I'm selecting the case that gives me the highest load and then you Usually you have like the sustained case, you have the expansion, amplitude or range, depending on how you made your load cases. And I'm selecting all of those, and I'm selecting the restraint summary. Because then I can see if, for example, the thermal in this case, it was thermal loads, that was very dimensioning. So you obviously had 90% of the loads for thermal. Okay, what do I need to know? If it's thermal, do I need to add flexibility? If it is, for example, due to Vegas, for example, that's your problem, because you got some sideways exploration going back and forth, then you know that you need more support. Exactly. That's how I'm assessing? Do we need more support or less support? Or maybe sometimes we need quite a lot of support in that area to kind of get rid of the loads coming in from the outside. But in general, it's always good to take a look at even though you're not going to use your restraint loads from the expansion case, for example, you're never going to use that for anything else than just looking at them to understand what is the driving factor of your logo?
Luuk Hennen 1:26:13
Now, there's one more question, which sparked my interest? This is from Oscar Diaz, is it important to include the weight of the support shoes in the model? I mean, I've never done that.
Sondre Helgesen 1:26:29
No, I have never done it myself. I was curious. Yeah, I don't, I don't think that's of any importance. Of course, there are always special cases. It's like, for example, for subsea where we have a very big support on the end of manifolds, for example, we should call that the hub is like a hub connector system, right? So the hub itself, it might have 500 kilograms, yeah, 1000 pounds, and then it or maybe more times, for example,
Luuk Hennen 1:27:02
due to friction anyway, right?
Sondre Helgesen 1:27:05
It will move because the external loads are extremely high. We got in one case, in that high-pressure case that I talked about, we had 1300 kiloNewton meters of bending moment, for example. So though, that one might move. So we include that load that, sorry, not allowed, but the weight of that mass into the system. But for regular pipe support clamps and so on. No, we don't do that.
Luuk Hennen 1:27:32
Yeah. All right. All right. Um, so I mean, there are several more questions on that we Good, good. Because I also mean, as I mentioned, time flies. So we go into way more detail on many of these topics. And I think, you know, maybe we should in the near future. Were there any additional slides or things before I interrupted with the questions that you wanted to discuss? Yeah,
Sondre Helgesen 1:28:00
it was a little bit more talk about nonlinearities. And that's interesting. Yeah, that's, that's Yeah. So I think that let's use five minutes on this one. If you'd rather go and have another chat on this, this is a greater detail in the future. But this is a very simple setup, as you can see here, let's say you have a supported two-millimetre gap. And you have displacement or areas just pulling it down as early as possible, your dad right is always pulling it down. So what will happen is that the How to say it's the support will not act. In the beginning, that's that orange here is the force in the set direction. So to support light from the support load the restraint for force. So as you can see in the beginning, and you start moving it, nothing really happens. Because there is no contact between the pipe and the support. So it's just a step. I just made some steps to kind of see what happened. And then this is the force that the orange one and then the blue one is the deflection of the pipe. Yeah, the pipe will be moving linearly. until it touches over here. Yeah. Because it's a linear system until it touches a lot you can see that the behaviour of the system afterward is not linear. The same with the force as well. First, there's zero force and then there's this linear increase of force when we are linearly increasing the applied deflection, right? So when he talks to us, that deflection is going to get red forces over here. And that's what we see here. Yeah. It Depends on what software you're using. In season two, we are writing the underload cases like all the sub-load cases as well. In other software, then, for example, triflex, this is done in the background, so you have the subcase is being subtracted automatically. But in this case, I mean a very simple comparison, it's like, we got two loads, one the seven, I don't remember why I call it the seven of the two. But anyway, the one is, the seven is two times the one basically. So let me move it with D one, there is zero force, but we got 1.2 97 millimetres of deflection, maybe this is a little bit hard for, for people to see Saville, I will skip to this one, we enlarge it a little bit. So so when you remove it with D one says the deflection that we added into Sisa, two, there are zero contacts zero force. And the deflection is 1.3 millimetres. That means that if you have a two-millimetre gap, as in this example, we still have Oh point seven millimetres before it touches, right? And then these seven are two times the one. Then it had contact. And deflection is two millimetres. And that's quite obvious because we limited that deflection to two millimetres. Exactly. So so.
So then, then we get a force, it's in contact, then we just say, what happens if you take the one plus the seven. If you didn't like, the regular math, like one has 07 has 1135. So the answer should be 1135. It shouldn't put, let's say that you were thinking that that would be wrong. And I will show you why it's not correct because it's nonlinear. But also, because here, if you then do D one plus d seven, then we are displacement one plus displacement seven, that means that we have three times d one, and that means that we have 3614 Newton's in reaction force in the support, but the deflection of the support is still the same. Because we are having a gap and the gap can never be more than the gap itself. Unless you add stiffness, then it can move more. But let's take the statements out of the equation right now. And then eighth, in case nine, they're doing the same thing. In this case, we just took three times the one, as I said, the seven is two times the one. So this is three times the one and that gives the same answer in cases eight and nine. Oh, that's good. That's shows that are working Exactly. But then in the case, 10, we are just typing in L one plus L seven. Meaning that we take case one plus case seven. And what is happening inside of Caesar in that case, it takes the numerical values you got already, zero plus 1135 is 1135. Yeah, it takes 1.297 plus two, that gives you two 3.2 97. And here, you can clearly see that there's something weird going on.
Luuk Hennen 1:33:13
So basically, what this shows is that adding the loads, and then doing the full calculation of how the other loads are distributed in the system gives a different result than having a look at the separate loads and then combining the results.
Sondre Helgesen 1:33:29
So what I'm trying to say is that when you combine the results or subtract, subtract, this is typically safer, because then you get what they call the leftover, so to say, and you get the correct support conditions and so on. But I have seen sometimes people are like, okay, but why can't I just add the different loads, like temperature, one pressure, one weight, and everything, we just add in a different load case, and we sum them up in the end? Yeah, well, it's a nice idea. But then you just sum the values together, you don't sum the real conditions of your system. Unless it can work if your system is a linear system. Yeah, yeah. And there are zero gaps, there is zero friction, then that can work. But in cases when there is a gap, well, or you can lift off in that sense. Liftoff, right, huh, yeah. where I left off, for example. Yeah, exactly. So, in the course, we're gonna talk a lot more about these kinds of combinations and how it matters why you take one operational case minus another operational case to find the occasional stress, for example or to find the temperature range and all these kinds of things. It's got to be much more clear. All right. Yeah. Awesome. And just before we round off today, I see that we are 30 minutes over. But if we got a special request for how to model a swivel joint. Meaning that if you have, for example, a flame shed This is allowed to rotate around one of the degrees of freedom. That's basically what it is: we need to open up one of the degrees of freedom. So this is just a simple test I made earlier today, just to kind of prove the point, it's that, in this case, we have anchor up here we got the piping element node 15 to 20, which might be a little bit small to see. And then it's not connected, this element is not 20 to 30, this element is 20 123. Because we're going to use a C node as a connection node. So in this case, we use node 20 as the main node and then the C Now this node 21. And then type x type y type C, that means that we are restricting movement in X, Y, and Z. But we do it in the relative coordinate system to the elements, not to the global system.
Luuk Hennen 1:36:18
So you basically connected both piping sections in those degrees of freedom. And then
Sondre Helgesen 1:36:24
and then we do the same for a rotational x r y. And then we got the RC, if you left the RC out of this, it would not be connected, then you have a fully swivel joint. In this case, I just wanted to show that you can also add for example a gap in it. So if you have a rotation we've done sometimes for subsea that is actually almost like a ball joint, it's very interesting. So when you have to bend on it, it can move up to three degrees, I think plus-minus three degrees, the range is 60 degrees. And, and if it moves more, then it's stopped. So in that case, we would type in three degrees as the gap here in the direction that we wanted. The benefit here is that now we can see that if you get a force or not a force with a moment, of course, that means that the gap is closed and that we have exceeded or hit the limit of that swivel don't or the board ball joints.
Luuk Hennen 1:37:25
Do they do so joints provide like zero? strength in those directions?
Sondre Helgesen 1:37:33
Yeah, zero or low friction, or even some of them do provide some friction. I'm not sure how I would model that into Sisa, too. But I've done some modelling of those into triflex. For example, where we define the rotational stiffness, exactly, I can actually do it here as well, you can add the rotational stiffness, then you can actually model it,
Luuk Hennen 1:37:56
maybe even bilinear rotational support if you have to, like fractions. Okay, maybe
Sondre Helgesen 1:38:03
Yeah, it's not that often that we use them anyway. But so I just made three load cases D one, D, two D, three 0.5 degrees rotation, one-degree rotation, and 1.5 degrees rotation. So that's that arrow here with torque around it or a torsion. So, V One should not generate any reaction load, B two should also not generate anything, but D three should generate something. And that's what we can see here. In the anchor over here. In the red one, there are zero loads. In the first two cases 0.5 and one-degree rotation. In the last one, we get a reaction moment. of 1046 Newton meters. Yeah, this is transferred through this joint over here. The glide gap is closed. Yeah. All right. That's the way modelling swivel joints are basically modelling degrees of freedom. It could be maybe it's not a pipe continuing. And it could be like a support that's connected to another pipe. It could be this. See notes can be used for a lot of things. Yeah, definitely. I mean, and in other software, it might be called something else like release elements, Link elements, joint elements. Yeah, basically a lot of different names for them. But they all do the same thing. All right. I
Luuk Hennen 1:39:27
I have one more question which I find really interesting. Was this from her? Non, thanks for asking the question. It's a little bit related to the visual that you have on the bottom right of the screen. So the vectors and the force vectors and in different directions. The question is, why can you put uniform loads of x, y, and Zed in separate vectors, factor one for X factor two for y vector factor three for that, whereas you can also put them In one vector and then use the different components of that vector. Yes. I mean, I mean, my first response would be to get more knowledge about the load and the response of the system.
Sondre Helgesen 1:40:14
Right? Yeah. But I think also, maybe maybe I'm answering wrongly here. But I think also what he's asking is that what we very often do in stress man is that let's say that we have a displacement over here, but we might have a lot of combinations of that displacement. As you know, Luuk, I think there are like nine vectors. Yeah, it's nine vectors here. You cannot have an infinite number of vectors, not at least not in CS 220 19. All the software, you can do that. But the way of doing it here is that you define, for example, vector one is the x type of just a number one in here, 111, you make it like a diagonal matrix here, which is just typing 11111. Meaning that the one in your analysis, so the one-millimetre deflection or one inch or whatever your units are, is in the x-direction. And then in a y-direction, is it means that the two is going to be one-millimetre deflection in that direction, and that's how we can build it with a lot of cases, because you can, right, as I was showing here, you're going to have three times the one. So if you want to move the case, one of the cases you want to move the pipe three millimetres, not one millimetre, you just have three times the one. Yeah. And then maybe you want to lift it up two millimetres in the y-direction, you type plus two times the two. Yeah, exactly, and so on, and you build them the build cases. And in sub c combinations, we can have 64 128 cases, basically, the mind is the limit there. So we try to kind of limit it down to 264 128, sometimes 256 cases. But I've been up to 4096 cases, one time, that's crazy in combinations of these theses, directional vectors, and so on. So
Luuk Hennen 1:42:16
yeah, but I think that's a valid answer. So my first take was to put them in different vectors associated you can find you know, the influence of each component and a better understanding of the stress responses due to each I mean, a high load of displacements in one direction, might solve your issue, while the other direction doesn't really matter, but then also combine all of them in one load case, in the end, to see, of course, the combination. But I think your point is valid, you know, if you just use the matrix like this one, as you fill it with ones in the diagonal, and zeros and the other ones, then you have full flexibility in the load cases, to make combinations any way you want to, it gives more insights in my pain as well because then you have like one lowercase table, which has all the representations of the different loads in there.
Sondre Helgesen 1:43:11
And as I said, sometimes we don't have enough vectors so we need to copy up more files, but itself having more files you can use a diagonal, it also goes for accelerations for example, and it goes for forces you can use the same diagonal vector webinar to get a hexagon on this earlier which is called a shallow dive into deep waters. That is, that is addressing exactly this. This topic. Interesting. Yeah. Awesome. All right. So can they find the webinar somewhere? On hexagon's homepage somewhere? I mean, what I think we can do after the data link there, I'll and people can,
Luuk Hennen 1:43:56
I'll make sure, spend some time organising the show.
Sondre Helgesen 1:44:02
If you still see my screen, oh, it's quite small text over here. But on the side here, you can see that there are webinars if you have CCT and then yeah, I can actually click on it so
Luuk Hennen 1:44:16
I'll put in the show notes somewhere and for everyone listening perfectly. And I mean, you know, there might be people that are not Cesar who uses the listening so might be relevant or not but we discussed several topics that are outside you know, engineering training scope. So some might be regarding this webinar or regarding software that we touched base on. I can just list them below this video.
Sondre Helgesen 1:44:46
Yeah, exactly. So on the top here, right now, I highlighted the link. If you're still showing my screen, though. So and it's like you're saying this is of course in Sisa to that webinar, but still, it gives some insights on subsea engineering and subsea calculations in accordance with estimates, those are not estimated, but as maybe two to 1.8. And, and, and also some brief talks about the DMV, OSF 101. They change the name, though, but I think it's interesting and I usually you watch a lot of different type of webinars, even though we don't have the software, it's always something we can pick up in and learn from, from the different software's and not software's, but from different webinars,
Luuk Hennen 1:45:34
I would say this topic regarding the building load cases, etc, will definitely be addressed in more discussion and detail in the course. Yes, starting in February, then you have, you know, a lot of time to do, like more detailed discussions. I mean, I'm, I suggest to start wrapping up, Sondre, I mean, we've been talking for well over one and a half hours, which has been great, thanks. Thanks for your time. Thank you. And having said that, you know, I enjoyed it a lot. And I think, you know, the more we talk, the more topics come up that is worth discussing further. But we won't do that today. Perhaps we will find the time soon. I would like to, you know, point all this out to all listeners, you know, that we'll add the details of this discussion in the show notes and have a look at the upcoming course. Let me just show you the discount coupon one more time. Yeah. Yeah, there you go. So, so, there will be a course that starts on February 8, and that will This will include 16 hours of you know Sondre, Juan Yana Don, senior people in his in the Stressman team discussing a lot of topics related to bio stress and basically building like a complete overview of the field you know, we designed together with Stressman an engineer we designed the course such that it is we feel perfect for five stress engineers Junior process engineers would say zero to five years of experience but also designed piping design engineers piping lead engineers especially that need to grasp like like the basics of pipe stress even though they don't have to do the analysis themselves. So the course has been set up for those audiences you know if that sparks your interest Have a look at engineering trainer.com and then displacement courses you can use the coupon that is on the screen at the moment stress on an online course to get a nice discount.
Sondre Helgesen 1:48:10
Yeah, that's perfectly wrapped up I just wanted to add that as you say it's going to give a good overview of almost every topic there is the pipe stress of course we don't think that deep into a lot of the topics but we got to dig deep when it comes to primary and secondary loads and stresses that is something I see is a lot of confusion on in the market. And what do these verbs actually mean? And principle Why is the allowable stress much higher for secondary stress than primary stresses or so on so that's going to be discussing details the same the load combinations, we are going to try to really make people understand what they're doing and that's my mantra when I'm doing stuff it's like I want to understand why it's like that I don't need people to tell me "Oh, you do this there's this exactly but that's a part of the course is like we try to at least these kind of topics we try to give me a bit of the background of it and so you actually understand it rather than just copy pasting."
Luuk Hennen 1:49:20
what I'm doing Yeah, pushing buttons. Yeah, I totally agree. Yeah, pushing buttons. Exactly. Alright, so on that night. Yeah, let's wrap this up. I mean, I'm sure Sondre I will shoot you new requests or invites to have online discussions. I mean, we might take a little bit more closed scopes and do a little deep dive that will be nice on the day. But, you know, for all of you listening, I invite you to subscribe to the YouTube channel. That's one of the best ways to see the new live streams coming up. We intend to do one every week on EngineeringTrainer TV. With different specialists and experts that we collaborate with, follow the LinkedIn pages of Stressman engineering and EngineeringTrainer. That's also one of the more important social media outlets that that well at least we and I also think Stressman uses. And thanks for joining us. Thanks again, Sondre, for your time and have a great day to all of you.
Thank you, Luuk. You take. All right, I got one. Cheers.
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