FreeCAD FEM Tutorial - Getting a result

hello and walk in my channel today I'm gonna be showing you how I got this result this result is in a fem where is in the FEM workbench and basically this video is you know a tutorial on how to get your first result because I found it was a little bit difficult in the FEM workbench to get a result and I didn't I have tried to record this video a number of times and every time I come back I had you know I had some other issue and that might be largely in part two I have no idea what I'm doing in FEM and this is strictly about getting a result in the FEM workbench I find that the whole thing fascinating and I think even with someone with very little understanding of it things like this are an obvious tell of that there's you know of what the forces and stressors are and you can ignore that bird in the background it's just a clock that makes the bird noise every on the top of the hour so basically you know what we have here is we have two types of constraints this is a forced constraint pushing you know in this vector and this is a fixed constraint down here holding the bottom and these are the stresses as a result so I'm going to try to show you how I got to this result and I'm gonna be focused just on on this object and we'll start out by making that object and the reason I'm gonna do that is because it's a little bit of a plug for my workbench that you know it's not a great workbench but it's it's fun I find that repetitive shapes you know these are called sketch or shapes I don't want a full part but I often do various shapes over and over again so this is workbench allows me to save off those shapes and get them recreated and I try to create them in a way that's you know a little bit flexible so what I'm gonna do is I'm gonna stick this in a part and we'll just put this in a body and I'm gonna stick it to the y'see plane and so that should get me yes so I I usually want it so that it's going to be visible when I set to the isometric view so let this let me change this to the XZ plane I think would be better oops so what you do is you do change the support here and this is a this is a sort of a newer way to do it okay so now when I now you know after I've been moving around and I hit this it's going to give me a view that's most meaningful to me so I'm gonna pad this to a hundred and then we'll make it symmetric to the plane so that's you know very let's make it fifty instead it so it seems a little bit big so you know this is no good no rhyme or reason this just what what has ever works now the reason I made it symmetric to the plane is that when I add the next sketch I'm gonna be able to do the same thing I'm going to do the XZ plane this should get me on edge there so now he's now I'm I want this to be in the middle so I'm going to use and I'm gonna use at the fair which is called again external geometry constraint so I'm just gonna create a triangle here and I'm you know selecting the coincident constraint with each one of those end points and that should be good so now when I close this I got my triangle and I should be able to just pad this and oops so it's not tied this one of them didn't connect oh there it is I thought I got it but I didn't so let's finish this real quick and then we'll get on to the then we'll get on to the M make it 10 that's good I'm gonna be symmetric so write it very easily without thinking too much it's centered so that's that's the kind of thing I like a workflow that centers you know you know does work for you so let's go into FEM now and so what we're gonna start with this every every FEM needs an analysis container so I think you can do multiple ones per but I've had issues when I tried to do that so I you know I don't do it for now and then every analysis needs a solver so we're just gonna add the calculus calculus solver and I think okay so I added three because it wasn't expanded I like to keep this hidden but if in this version that pops up whenever there's an error I'm not a big fan so the next thing I need to do is I need to add a material so everyone needs a material and the solver and I'm just gonna do PLA plastic because that's the kind of thing our material I've been working with lately and I'm just gonna leave it all as a default for now because I don't understand any of this anyway and then so finally we need to the next thing we need to add is so this is all set up sort of stuff the next thing we need to add is a mesh so the only thing I have installed is G mesh and actually this reminds me of something so I'll tell you in a second so I'm gonna hit apply I think I need to select a shape first though nope it was already selected so that's done when you get this result it's worked if you get anything else here it hasn't worked and you should get the mesh on the object at some points I wasn't able to do it from a shape but it works for it for now so we'll just leave that there so it hides the mesh by default but you can bring it back a couple of other things calculates you have to install the calculates package and you also have to install G mesh so that's something you have to do before you even use yeah de femmes the FEM tool the FEM workbench so the next thing I'm going to do is I'm gonna add the constraints so to add the constraints I'm gonna just orient the SOI I want it the first rung that ad is the fixed constraint and that's by the lock here so I'm gonna just click on it and it asked it gives you our prompt it says add two faces so I'm gonna select the face I want and add it and you see right away it's added the constraint so that that works out very well and then I'm gonna do the same thing for the force constraint that's this one right here create force select the face at it and you'll notice it's going the wrong way and this one so I'm just gonna hit reverse direction okay so now I've got my my constraints that I need so the next step is to actually run the analysis so with the solver selected you go to see where is it and this is this is the kind of thing that bugs me there's an actual or do I need something else see if I forgot something nope so I need to run the analysis so it used to be a cube and I'm trying to figure out where that wearable is again I wonder if I can just do it from so when it runs the analysis let me I'm gonna have to nope that's the GMs so sometimes you have to have the things selected that are gonna work on it hold on one sec oh okay so it's this is the the icon to run the solver to I get it to pop up yeah so that runs it for the selected for the selected solver so this is my solver and I'm gonna just click run and it should give me an okay I thought it would give me a dialog but so those are the results so the next thing we can do is once oh and I think this is important this is why I didn't get the results this time is is the the first time you run it you have to do this you have to do change you have to change the attributes and you have to do this run InP file it creates the file and then you have to click run calculates calculus so that must be done before you can actually rerun it so the reason I was able to get a result without rerunning it and I you know surprising myself for a second was because I had done it once now now that I have the result I can I can view view the effects so if we go into this the visualize we get this dialog right here and by default it goes into I think it by default it goes in the displacement magnitude now and that's how we get our result it's so it's not hard but it's not obvious unless you have an external resource to help you understand what you need to do it may be easier if you're a fem person you know I don't know but you know one other thing that this allows you to do is and doesn't work on this one is um if you have something that's going to deform you can you can you can actually show the deformation with with this slider here so if this was like a long beam it would show the beam bending I can't get it to do do it on this but like if you do deeply displacement X you'll actually see the some some lines perhaps let's see maybe I think some of the lines might change now it's not doing it but um I think I have to go ramp this way up well anyway no I won't play with that so you can and maybe in future videos I'll experiment without I've gotten to work with longer objects but these shorter things you know I'm missing something but that's pretty much it if you want to learn more about my sketcher shapes workbench head over to you can go out of my patreon page I'm gonna put details there and places where you can upload it it is on get but I'm gonna save that for the patreon page because I'm trying to drive a little bit of traffic to that I'll be honest so if you like these videos make sure you subscribe and you if you click the alarm bell you're gonna get notified better and thanks for watching I really appreciate it I enjoy doing these and I enjoy having you as a viewer I have a great day oh okay so it's this is the the icon to run the solver let's you don't get it to pop up yeah so that runs it for the selected for this selected solver so this is my solver and I'm gonna click run and it should give me an OK I thought it would give me a dialog but so those are the results so the next thing we can do is once Oh and I think this is important this is why I didn't get the results this time is is the the first time you run it you have to do this you have to do change you have to change the attributes and you have to do this run InP file it creates the file and then you have to click run calculates calculus so that must be done before you can actually rerun it so the reason I was able to get a result without rerunning it and I you know surprised myself for a second was because I had done it once now now that I have the result I can I can view view the effects so if we go into this the visualize we get this dialog right here and by default it goes into I think it by default it goes in the displacement magnitude now and that's how we get our result it's so it's not hard but it's not obvious unless you have an external resource to help you understand what you need to do it may be easier if you're a femme person I no I don't know but you know one other thing that this allows you to do is and doesn't work on this one is um if you have something that's going to deform you can you can you can actually show the deformation with with this slider here so if this was like a long beam it would show the beam bending I can't get it to do do it on this but like if you please displacement X you'll actually see the some lines perhaps let's see maybe I think some of the lines might change now it's not doing it but um I think I have to go ramp this way up well anyway no I won't play that so you can and maybe in future videos I'll experiments that I've gotten to work with longer objects but these shorter things you know I'm missing something but that's pretty much it if you want to learn more about my sketcher shapes workbench head over to you can go out on my patreon page I'm gonna put details there and places where you can upload it it is on yet but I'm gonna save that for the patreon page because I'm trying to draw it a little bit of traffic to that I'll be honest so if you like these videos make sure you subscribe and you if you click the alarm bell you're gonna get notified better and thanks for watching I really appreciate it I enjoy doing these and I enjoy having you as a viewer I have a great day

Channel: mathcodeprint

Views: 56,964

Keywords: FreeCAD, Tutorial, cad, enginering, design, 3ddesign, fem, 3d analysis, enginering design, design analysis, drafting, drafting design, open source, cad design, cad drawing, cad engineering, cad software, cad systems, computer aided design, design software, drafting software, freecad 0.19, open source software

Id: Pt870A2nFDo

Length: 13min 8sec (788 seconds)

Published: Thu Apr 16 2020