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#1 Opening But List...

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nobody
None
9
2002-03-04
2002-03-04
No

Hi,

we would very appreciate to get feedback from people
using FELyX (if there are any?) about problems, bugs,
needed extensions etc...

If somebody is implementing new features we would
also like to include'em in FELyX ...

Greetings ok

Discussion

  • Nobody/Anonymous

    Logged In: NO

    Hi everyone,

    I am a graduate student who has started working on
    evolutionary structural optimization. I have downloaded
    FELyX-0.21 from the website, along with its folders
    containing the element library and source code. I am using
    Microsoft Visual C++.NET on Windows XP and would need to
    use the Plane-182 element (for 2-D plane stress/ plane strain
    problems) in the FELyX library. I have encountered some
    problems enroute. Could someone help me with the following
    ?

    1. The source code of the 'AssembleElement2Gsm' method of
    the 'Element' class specifies that the global stiffness matrix
    be of type 'EnvelopeMatrix'. But the html doc files indicate a
    type 'mtlMatrix' for the global stiffness matrix. Neither class
    seems to exist ?!! I searched all the 'FELyX' and 'MTL' folders
    I had downloaded but couldn't find an 'mtlMatrix' class. So,
    how do I assemble the element stiffness matrices and form
    the global stiffness matrix?

    2. I have created boundary conditions using objects of
    the 'BoundCon' class. But how do I specify these boundary
    conditions at specific nodes of the structure?

    3. If I do succesfully assemble the GSM, how do I solve the
    resulting system by incorporating the displacement and force
    boundary conditions that I have created using objects of
    the 'BoundCon' class?

    4. How do I obtain the new coordinates of each node (after
    deformation), i.e, how do I obtain the solution of the final FE
    system and get the new nodal coordinates?

    Looking forward to generous help from anyone who's willing to
    share their knowledge on any of the above problems I have
    encountered.

    I am hard pressed for time and would immensely appreciate a
    reply to the above at the earliest.

    Looking forward to many fruitful interactions with the FELyX
    community,

    Thanks,
    Karthick
    Please reply to: kc299@cornell.edu

     
  • Oliver Koenig

    Oliver Koenig - 2003-07-29

    Logged In: YES
    user_id=379995

    Hi,

    I can make some comments to your questions:

    1) You say you use version 0.21 of Felyx. I would highly
    encourage you to use download the actual CVS version
    instead, since we are late with providing a new release.. The
    CVS version contains many enhancements and new features
    as well as some redesigns...
    Instructions for anonymous CVS download can be found on:
    https://sourceforge.net/cvs/?group_id=39864

    2) Compiling on Visual Studio .NET
    We actually did never compile FELyX on Windows. So there
    might some bugs that need to be fixed for that. But we would
    highly acknowledge if somebody would do that. The external
    libraries used in FELyX as Boost or as MTL should work on
    Windows (at least they say so...).
    On the other side, if you have access to a standard Linux box
    with gcc 3.x, things would be much easier for you...

    About your specific questions:
    ------------------------------
    --Type of the global stiffness matrix:
    In the actual version look at the class FelyxObject and the
    derived class StructObject. There you can see how a static
    analysis is set up, and how the different matrices are defined.
    For the direct sparse solver (which I would recommend to
    use) we use an MTL envelope matrix format defined as:
    mtl::matrix< float_type , symmetric<lower>, envelope<>,
    row_major >::type

    -- How to link Boundary conditions to nodes:
    In general a node (as defined in class StructNode) has a
    member BoundConPtr which holds a pointer to boundary
    conditions...

    -- How to solve
    Look at method DirectSolver() of class FelyxObject

    -- the method DirectSolver() ends with a deformation vector,
    giving deformations for each degree of freedom of each node

    I hope this makes a few things clearer for you ?
    Do not hesitate to ask if further questions arise...

    Greetings
    ok

     

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