+ Reply to Thread
Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 24

Thread: beam element FEA

  1. #1
    Yeah, this is another FEA thread related to the chassis...but I dont think this has been discussed yet.

    How do you do a beam element FEA? I draw say a single line in mechanical desktop and then try to bring it into ansys 9.0 workbench but it is unable to. I was told Ansys was capable of doing this...was I told wrong?

    Do any of you guys have any experience with the Mechanical desktop/Ansys combo? We also have Algor and cosmosexpress available to us, but again we havent had any luck. There must be something simple that I am missing.

    I have a year and a half of experience FEA'ing various parts with Ansys, but they have always been solid models.

    thanks for any help... I am not asking for anything to be handed to me... just point me in the right direction.

    --Adrial
    Rutgers Formula Racing 04,05, 06

  2. #2
    Yeah, this is another FEA thread related to the chassis...but I dont think this has been discussed yet.

    How do you do a beam element FEA? I draw say a single line in mechanical desktop and then try to bring it into ansys 9.0 workbench but it is unable to. I was told Ansys was capable of doing this...was I told wrong?

    Do any of you guys have any experience with the Mechanical desktop/Ansys combo? We also have Algor and cosmosexpress available to us, but again we havent had any luck. There must be something simple that I am missing.

    I have a year and a half of experience FEA'ing various parts with Ansys, but they have always been solid models.

    thanks for any help... I am not asking for anything to be handed to me... just point me in the right direction.

    --Adrial
    Rutgers Formula Racing 04,05, 06

  3. #3
    I wouldn't trust Cosmosexpress...

    Mechanical desktop? I feel sorry for you guys.

    So you're trying to basically take a 3d line drawing, bring it into an FEA suite, and define those lines as structural members and then analyze it? Can't say I've got the solution to your problem, but the quick and dirty way of doing it would be to just sweep solid bodies along all those lines, trim as appropriate, and analyze that.
    Colorado FSAE | '05 - '07
    Goodyear Tire & Rubber | '07 - '11
    NASCAR Engineer | '11 - ??

  4. #4
    <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
    ....How do you do a beam element FEA?...

    ...We also have Algor and cosmosexpress available to us, but again we havent had any luck. --Adrial </div></BLOCKQUOTE>

    I use Algor to analyze tube frame race cars and it works well. I use an older version (V12 and 13) and like the relatively simple set of drawing tools it has.

    ANSYS will certainly work but it is a more complex package. It's mainly a function of what software package you are used to but you might give Algor a try. It's easy to combine shell elements with beams to model sheet metal gussets.

    Oh, and you are going to check your results with a simple test piece regardless of which software package you use, right?

  5. #5
    It's easy if you use Ansys not shi**y workbench. Make two keypoints in Ansys, then make a line, define section or real constant, set line divisions and then line mesh. There is no "3D solid" geometry to beams. If you use section properties you can turn on element shapes by typing "/eshape,1" at the command prompt. Then it will look "3D". To turn off element shapes replace the "1" with "0". Ansys is the way to go with designing these frames. You should be able to figure out the rest.

  6. #6
    I would suggest NOT sweeping solid bodies along your lines as the calculation times will skyrocket. ANSYS is a little funky but I have had success importing an IGES file from ProE and defining the elements from there. The easiest way I have found to do frame analysis is using ProE/ProMech. I can change the frame and re-run the FEA in less than 2 minutes. Super easy, fast, and its all in one package.

    -Redbeard
    Dartmouth Formula Racing

  7. #7
    <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The easiest way I have found to do frame analysis is using ProE/ProMech. I can change the frame and re-run the FEA in less than 2 minutes. Super easy, fast, and its all in one package.

    -Redbeard </div></BLOCKQUOTE>

    I think we have promech but I haven't used it yet. I will give that a shot. How do you have the frame drawn in pro/e when you bring it into promech? We have the chassis drawn in pro/e as a solid model, with points at every node so this would be the easiest way for us.

    thanks for the tips

    --Adrial
    Rutgers Formula Racing 04,05, 06

  8. #8
    So, you are probably using pipes to fill in between the points. The best way would be to suppress all the pipes and replace them with just simple datum curves. Then, switch over to ProMech and define you idealizations (beams), loads, and constraints. You can define different beam elements and select all the appropriate curves. Assigning loads and constraints is as easy as picking the points and giving them values. Then, run the simulation, on our 3ghz machine it takes around 5 seconds. Viola! Hope this helps. See if you can find someone who knows ProMECH because nothing in either of these programs is easy to figure out on your own. PTC puts out the most non-intuitive software on the planet, but once you learn it, you're golden.

    -Redbeard
    Dartmouth Formula Racing

  9. #9
    Awesome. We do have promech and it looks like it'll work great.

    We will have to redraw the chassis because some of the points are referenced off of protrusions...but that shouldn't take too long. I did a quick FEA of a single axis and everything looks good...

    thanks a lot everyone
    --Adrial
    Rutgers Formula Racing 04,05, 06

  10. #10
    We have the chassis drawn up and have assigned properties to each of the tubes using primarily the point to point reference system.

    Whenever we attempt to run the FEA (regardless of number of constraints or loads), we always get an error saying "The model is insufficiently constrained for the analysis.
    Please review the element connections, properties, and
    constraints."

    I have run a simple FEA on 3 points with no trouble.

    Does anybody have any suggestions?

    thanks for any help,
    Adrial
    Rutgers Formula Racing 04,05, 06

+ Reply to Thread
Page 1 of 3 1 2 3 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts