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Importing geometry to Ansys

  • 22-10-2012 4:16pm
    #1
    Dunphus
    Closed Accounts Posts: 138 ✭✭


    Anyone handy with Ansys?

    I'm looking to do some buckling analyses of some stiffened cylindrical shells and I'm having a bit of a pain modelling them in Ansys and also importing them from other CAD programs.

    The problem is I have a thin cylindrical surface that is broken up by ring stiffeners (Stringers to be added later) and I need to basically create a part so they are modelled as one integral structure.

    I know that I need to create 'surfaces from edges' for each of the cylindrical sections between the stiffeners but I can't see how I can do this in the Ansys geometry modeller (I make a circle, try to do this and it just creates a circular plate as opposed to a cylinder).

    Anyway, I have tried Autocad and Rhino 3d to import the cylinders in but the meshing is a bit troublesome, I have to do pinching and stuff which doesn't give me a consistent mesh around the cylinder so I'm not getting symmetric buckling (i.e the bays on one side are deforming more than on the other side). Not to mention sometimes it just makes an absolute bags of the geometry somehow; parts of the ring stiffeners moving from inside the cylinder to outside etc.

    So I was wondering if anyone has any tips? Maybe another CAD program suggestion? Pro-engineer? Solidworks?
    It's part of a thesis so I should have access to a plenty of software through the university. I'm thinking there must be something that can model the geometry 100%, then it can be imported into Ansys for the FEA alone.

    There has to be a simple fix but I'm getting pretty frustrated at the moment.

    I'm using Ansys workbench 13


Comments

  • #2
    breadmonkey
    Registered Users, Registered Users 2 Posts: 3,608 ✭✭✭breadmonkey


    Hey man I'm not being funny but is there any other FEA program you can use? I used it for my undergrad thesis and in my masters and I've always found it to be an absolute nightmare.


  • #3
    enda1
    Registered Users, Registered Users 2 Posts: 5,166 ✭✭✭enda1


    I know little about ansys, but consider nastran or radioss(optistruct) with a part meshed in hypermesh or ansa. For geometry modelling, there is nothing better than Catia.


  • #4
    kevohmsford
    Registered Users, Registered Users 2 Posts: 3,317 ✭✭✭kevohmsford


    I just use SolidWorks to create the part then save the file as a parasolid. Then just import the file to Ansys.
    I never liked modelling with Ansys.


  • #5
    Dunphus
    Closed Accounts Posts: 138 ✭✭Dunphus


    breadmonkey wrote: »
    Hey man I'm not being funny but is there any other FEA program you can use? I used it for my undergrad thesis and in my masters and I've always found it to be an absolute nightmare.

    I remember some people using it in their bachelor dissertation alright. Was it yourself and McGetrick or something? I'm guessing if it was that long ago it was nothing like Ansys workbench 13 or 14? Were you guys using APDL? Ansys really is a great analysis program, I said to myself I wanted to learn it so that's why I chose it for my thesis. I've gotten reasonable with it, it's just importing models that's giving me hassle (No doubt I'll run into other complications though!). How was it giving you hassle? I'm planning on only doing some linear buckling analysis and a few non-linear analyses so I won't being doing anything as troublesome as structural dynamics or anything.
    enda1 wrote: »
    I know little about ansys, but consider nastran or radioss(optistruct) with a part meshed in hypermesh or ansa. For geometry modelling, there is nothing better than Catia.

    I was actually considering using SAP 2000 which has a buckling analysis mode but I'll look into this other stuff, particularly Catia.
    kevohmsford wrote: »
    I just use SolidWorks to create the part then save the file as a parasolid. Then just import the file to Ansys.
    I never liked modelling with Ansys.

    I figured something like solidworks would be the way complicated models are imported. I reckon I will give this a quick go then. Never used solidworks before but I'd imagine most of these CAD software programs are more or less the same.


    Thanks guys


  • #6
    enda1
    Registered Users, Registered Users 2 Posts: 5,166 ✭✭✭enda1


    Don't use Catia for analysis, just for creating the geometry. It gives spurious results with its 2D elements.


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  • #7
    kirving
    Registered Users, Registered Users 2 Posts: 6,129 ✭✭✭kirving


    Solidworks files can be pulled into ANSYS with no loss of information, so that'd be the most obvious one to use.


  • #8
    Dunphus
    Closed Accounts Posts: 138 ✭✭Dunphus


    Thanks guys. I got solidworks installed on my pc thinking it would be much the same as Autocad or Rhino 3d but was a bit surprised at how different it is.

    With some tweaking I got my meshing to work ok in the short term in Ansys but I'm learning solidworks on the side for when things get a bit complicated. It's a nice program actually, can do some analyses itself it seems and it even has a buckling analysis.


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