12 Replies Latest reply on Jul 28, 2014 10:35 AM by Simon Yang

Assemblie simulation

Fernando Navarro Jun 30, 2014 5:37 PM

Hello, i have a problem with an assembly stress simulation, Hopefully! you could help me, in the next image show the part, was made with weldments, isn't a regular profile, is aluminium profile,

with this, i made the assembly, with screws of toolbox, in the next picture i show it, even the sill with i tried strengthen the structure

So my problem is in the stress simulation, my fixed constraint are the lugs, and the force is show in the nexth picture, but appears the next message : define a rigid contact between the beam and the solid or draining.

So, is possible the simulation?, i've read that is so complicated for solidworks this type of study, but i need to know.

THANKS! please help me!

Any question or doubt more specific, let me know!

Re: Assemblie simulation

Shaun Densberger Jul 1, 2014 3:19 PM (in response to Fernando Navarro)

I'm a little unclear as to what you're asking exactly; can you provide some clarification about what issues you're having and what exactly your trying to simulate and capture from a results point?

That being said, you could simulate this with a beam element representation of the 80/20 extrusion profiles, but I'm not sure what the best way to represent the bolted connection between the beam elements and you lugs (at least with what is available in SW Simulation). One option might be to make beam element representations of the bolts and connect them to the inner surface on the holes.

Whatever method you use, understand that you'll have limited accuracy on results within the beam elements (particularly stress results) as well as the stresses at the bolted interfaces between the profiles and the lugs. I think the best approach is to look at reaction forces/moments at the joints and compare them against the allowable values given by 80/20 for whatever connection method you're using (single anchor, end fastener, joining plate, etc.). Do that same for the interface between the lugs and the profiles. Look at the reaction forces/moments and use them to calculate the total tensile and shear loads on your bolts.

Make sure to also do some hand calculates to check some of the values calculated by your simulation.
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Re: Assemblie simulation

Jared Conway Jul 1, 2014 9:13 PM (in response to Fernando Navarro)

your stress plot didn't get posted
also if you could post the exact error message screenshots that would be ideal
would highly recommend you start really simple and slowly add to your analysis
start with just the lugs, fix them, with gravity, then add the next part, rinse and repeat until you have the whole thing
this way you don't miss any contacts and you learn about how the model has to be build fot analysis as you go
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- Re: Assemblie simulation
  
  Fernando Navarro Jul 7, 2014 6:58 PM (in response to Jared Conway)
  
  Hello jared, i want simulate the stress study, i managed to mesh like the next picture
  
  But in the moment to run, appears the next message "Define a rigid contact between the beam and the solid or emptying"
  
  So my question is, how can i resolve this message? jus want to see how the force in the beam affects the screws and the lugs.
  
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  - Re: Assemblie simulation
    
    Jared Conway Jul 8, 2014 4:48 AM (in response to Fernando Navarro)
    
    Did you define contact between the solids and beams?
    
    Start by analyzing just the lugs.
    
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    - Re: Assemblie simulation
      
      Fernando Navarro Jul 18, 2014 4:52 PM (in response to Jared Conway)
      
      So, are you saying that is not possible the simulation between weldment, lugs and screws together? that was my goal, obtain a strees simulation of all the assembly, so is not possible?
      
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      - Re: Assemblie simulation
        
        Shaun Densberger Jul 18, 2014 5:38 PM (in response to Fernando Navarro)
        
        Jared is not saying you can't simulate everything; rather, he's suggesting that you start with a simple model and progressively make it more complex. You certainly can connect everything together, but keep in mind that results such as stress will not be accurate around the connection between the lug and the frame. This is because the fame is meshed with beam elements, whereas the lug is meshed with solid elements. Since beam elements and solid elements have some key fundamental differences between them, the software has to set up a series of equations to 'connect' them together (plus, beam elements can't give accurate 'local' effects since they are a 1D element).
        
        Once you're familiar with the software and how to make sure you've connected all your parts together properly, I suggest that for the frame and the connection point between the frame and the lugs, that you look at the reaction forces and then use those values to calculate (by hand) whether your joint is strong enough.
        
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      - Re: Assemblie simulation
        
        Jared Conway Jul 19, 2014 1:03 PM (in response to Fernando Navarro)
        
        shaun's explanation is exactly my point. if you or your company sent me the analysis, we could definitely do it. but there are a lot of considerations that you need to take into account based on experience. unless someone from the forum sets up your analysis and then shows you how to do do it, you'll need to build that experience. the easiest way to do that is start simple and build up.
        
        but it can be done in solidworks simulation.
        
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      - Re: Assemblie simulation
        
        Simon Yang Jul 21, 2014 10:00 AM (in response to Fernando Navarro)
        
        Sure! It is possible. Just use solid element.
        
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        Re: Assemblie simulation
        
        Jared Conway Jul 21, 2014 11:58 PM (in response to Simon Yang)
        
        hopefully you have infinite resources to solve! as chase mentions, you need a lot of elements to get a good analysis here.
        
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        Re: Assemblie simulation
        
        Simon Yang Jul 28, 2014 10:35 AM (in response to Jared Conway)
        
        Yes. I did some jobs cost hours, computer has 16G memory, plus mesh control.
        
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  - Re: Assemblie simulation
    
    Nicholas Luyster Jul 21, 2014 4:16 PM (in response to Fernando Navarro)
    
    Hi Fernando,
    
    Is that the exact error message you're getting, "Define a rigid contact between the beam and the solid or emptying"?
    
    If not, what is the exact error you're getting?
    
    All the best,
    
    Nick
    SolidWorks Simulation Training
    
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Re: Assemblie simulation

Chase Draper Jul 21, 2014 4:30 PM (in response to Fernando Navarro)

You can tell it to treat the faztek weldments as solids but your mesh is going to have to be super tight and it will take a long time to solve. I would probably get rid of the legs and the lower portion of the box and use fixtures to support it under the corners of the top frame. The more pieces you can eliminate the faster it will run.
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