2D meshing options question

[jeremyad87]

Hello,

     I am doing some coded work that has specified the element type to be used.  I need to know if Autodesk Simulation Multiphysics can use 8 node quadratic element in 2d mode?  I do not have the software so any recent version is fine.

Thanks

[AstroJohnPE]

A quick look at the documentation indicates that 8-node 2D elements (termed 2D elements with mid-side nodes in the software) are available for nonlinear analysis only.

I'm curious about your "code work" and whether you are expecting to import or export information from your work and Simulation Mechanical.

[jeremyad87]

I am using TEMA section 5 code which gives the proceedure for the analysis.  I also have a few other questions. can Multiphysics output membrane stress and bending stress? also I need to be able to define an initial displacement to the 2d structure. and can Multiphysics calculate the spring rate for a certain geometry?

  Thanks in advance,

Jeremyad87

[AstroJohnPE]

Hi Jeremyad87,

Is TEMA a code for pressure vessels and/or heat exchangers? If so, I wonder if what they call 2D is the same that Sim Mechanical calls 2D. To Sim Mech, 2D elements are used in a 2D analysis. The complete model is represented by a mesh that lies in a single plane. All loads are in the plane. All displacements are in the plane. The documentation goes into further details about the three types of 2D elements: axisymmetric, plane stress, and plane strain.

So, if you would be using 2D elements, the answers to your questions are:

1. separate membrane and bending stress? No. You would need to do a manual calculation to separate them. (If I remember correctly, plate elements in linear stress will display the membrane and bending stresses separately. Beam elements in linear and nonlinear stress will display the axial and bending stresses separately.)
2. initial displacement? Yes. Both linear stress and nonlinear stress have a type of load where you can specify the amount of displacement.
3. calculate spring rate? Yes. K = Force/displacement. You apply one of those (usually force), and the software calculates the other. You then do a hand calculation to get the spring rate.