Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. Erik Panos Kostson

    Excessive Pivot ratios in shell mesh

    I think that is OK - MAT4 is for bending-membrane coupling which can occur if material prop. say are are not symmetric with respect to the midsurface of the shell. Here is something from the documentation: The MID4 field should be left blank if the material properties are symmetric with...
  2. Erik Panos Kostson

    Excessive Pivot ratios in shell mesh

    I think the elements are plane strain elements (MID2 is set to -1 which is plane strain) - in PSHELL MID2 set it to 1 for MAT1 and it will be a mem.+/bending shell element- also the inner and outer tubes/sections are not connected with each other - as suggested run a modal analysis and you will...
  3. Erik Panos Kostson

    thread727-313308 Hi guys, Am

    Well if you have these values given then use mat8 that is orthotropic and used for composites For more info on mat2 see the help manual that describes these terms via the relation between stresses and strains, so it is the material matrix that relates the two. See this for some info on this...
  4. Erik Panos Kostson

    Concentration

    Try to refine the mesh a couple of times and see what happens with the stress there. Just to see if there is a mesh dependency on the results that needs to be addressed, as rb1957 mentioned
  5. Erik Panos Kostson

    thread727-313308 Hi guys, Am

    ...$ SURFACE ELEMENT PROPERTIES $-------------------------------------------------------------------------------- $ PCOMP* 1-1.000000000E-3 0.000000000E+0 +0000006 *0000006 0.000000000E+0 +0000007 *0000007...
  6. Erik Panos Kostson

    Ansys Spaceclaim Scripting

    never done that but it would be to use the api
  7. Erik Panos Kostson

    Coriolis effect in ANSYS

    I have little experience in rotordynamics but I have written codes for beam elements that include Coriolis terms due to vibration and internal fluid motion and flow so then this term comes in the damping matrix that is present in dynamics. See this and the theory manual for a description of...
  8. Erik Panos Kostson

    Ansys Spaceclaim Scripting

    There is a scripting guide in the help manual. This video is also https://m.youtube.com/watch?v=Av_1Jo1IjkI Finally in the last release r2,one can record scripting macros
  9. Erik Panos Kostson

    Modeling Joints in Ansys using Method Written using Nastan Elements

    You posted in tow forums - I suggest to post in ansys forum since it is relevant to that. Say shells (CQUAD), will be shell181 in ansys, RBAR (rigid 1D element), could be used as either CERIG or a MPC184 (this is a better/easier option) rigid ansys beam/element, CGAP in nastran (node to node...
  10. Erik Panos Kostson

    Modeling Joints in Ansys using Method Written using Nastan Elements

    Say shells (CQUAD), will be shell181 in ansys, RBAR (rigid 1D element), could be used as either CERIG or a MPC184 (this is a better/easier option) rigid ansys beam/element, CGAP in nastran (node to node contact) would be in ansys a legacy element called contac12. See the help manual on how...
  11. Erik Panos Kostson

    Guided Wave Simulation in 3D bent pipe

    Again for more specifics on how to apply a forced/disp. excitation in abaqus post this in the abaqus forum. (just apply either force or displ., and look at the corresponding wave, just try it - most often PZT or EMAT one applies forces since this is what they apply to the structure they are...
  12. Erik Panos Kostson

    Guided Wave Simulation in 3D bent pipe

    I would suggest to delete this and post in the abaqus forum. For your info normally a force is applied to excite ultrasonic waves - see work from Imperial College NDE group (Peter Cawley,...), they might describe how they are excited in one of their many thesis available on their website
  13. Erik Panos Kostson

    Patran:maximun wing deflection

    Never done much of wing design. As for the FSI part mapping and importing pressures should be OK. This ansys tutorial (fluent) does the same thing with a bit more automation, it basically maps the pressures from fluent on to the structural mesh like you did. So it is mapped on the skin of the...
  14. Erik Panos Kostson

    Material Model with Different Young Modulus in Tension and Compression

    ...set different compression stress strain data that would be a larger E mod, than tension and as set MP, then here is what we get, so not possible: *** ERROR *** For material 1 at temperature 20, the initial slope (4.E+11) of the stress-strain curve based on...
  15. Erik Panos Kostson

    Loading and Un-Loading of a FE Model for ElastoPlastic Analysis

    I use this example when teaching nl fea. Pipe with internal pressure above yield so the inner radius goes plastic. Unload that and the inner radius will go into compression. This is because outer radius material is elastic trying to go back during unloading thus squeezing inner radius into...
  16. Erik Panos Kostson

    Material Model with Different Young Modulus in Tension and Compression

    It is a plastic model and that is how it should be used, so I do not recommend the following . But if you have to and you are confident that this is OK, Try setting yield to something very high, say 10000mpa for tension and 20000mpa for compression, so it does not yield. I never done this so...
  17. Erik Panos Kostson

    Modal analysis of LSF building

    That does make sense - if most/a lot of your mass is at locations where the mode shapes have almost zero disp. it will not add much to the mass P.F.
  18. Erik Panos Kostson

    patran field

    Good that you managed.
  19. Erik Panos Kostson

    patran field

    In fluent you can map your pressure on a Nastran imported structural mesh - that would be easier. Workflow: - Import Nastran mesh to Fluent via the mapping tool (Fluent: File/FSI Mapping/Surface). - Map pressures, forces and temperatures from the CFD mesh onto the imported Nastran mesh. -...
  20. Erik Panos Kostson

    Acoustic cavity mode shape, Vehicle modeshape , Acoustic radiation.

    There will probably be more sound in the cabin especially if a structural mode excited coincides with an acoustic mode. Damping must of course play a role in the vibration amplitudes. This video might be of help. Unfortunately I do not have any experience in vibroacoustic modelling using...

Part and Inventory Search

Back
Top