General Mechanical

General Mechanical

meaning of constants in rmodif in apdl commands

    • st2021
      Subscriber

      what does "RMODIF" do? what constants does it modify? the official documentation says stloc is "Starting location in table for modifying data. For example, if STLOC = 1, data input in the V1 field is the first constant in the set. If STLOC = 7, data input in the V1 field is the seventh constant in the set, etc. Must be greater than zero." but this is not really specific - where can this table be viewed and a human readable name for each field provided? Thanks

    • BenjaminStarling
      Subscriber
      One of my favourite help pages is 2.2 of the Mechanical APDL Element Reference help. This shows all the elements avaliable in APDL.
      If we go to COMBIN14 from this help page, for example, the real constants are as follows. It is mainly non-structural elements that have real constants. All elements that have real constants will have them displayed as below on their respective pages.

    • st2021
      Subscriber
      Thanks, that's helpful! In CONTA174 what is the meaning of R1 and R2? In documentation it says they refer to radius of a sphere, but I have two rectangular blocks, not spheres.
    • BenjaminStarling
      Subscriber
      R1 and R2 in this instance are in relation to contact/target geometry correction, which is controlled by section data. In Mechanical this option appears at the bottom of the details window. Because the mesh is discretised, sometimes coarsely, the user is given the option to help the contact behave as if the surface was a true sphere or cylinder. If your two contact/target faces are not spherical or cylindrical, this should be blank (i think, maybe 0, or maybe it is not read regardless of value).


    • st2021
      Subscriber
      odd, in
      " target="blank">
      these R1 and R2 are set to 1, though the bodies are not spherical or cylindrical
  • st2021
    Subscriber
    at least R1 is
  • BenjaminStarling
    Subscriber
    If you are referring to the first line in the following command snippet, this is for keyopt 1, keyopt (key options) are not the same as real constants


  • st2021
    Subscriber
    Right - thanks - where can I find a list of key options in ansys documentation, please?
  • BenjaminStarling
    Subscriber
    same page that you find the real constants, just further up
  • st2021
    Subscriber
    Thanks! The ANSYS's new ui for help files is extremely annoying, on a 21" screen the page only shows 2cm high box for the docs content. is it downloadable in pdf format to your knowledge? i've copy pasted it into a word processor for now to make it easier to read
    keyopt,cid,1,1 - means "UX, UY, UZ, TEMP"?
    "rmodif,cid,15,1" - means Frictional heating factor of 1 (all energy goes into friction heat)?
    "rmodif,cid,18,0.5" - 0.5 of heat goes to one side, 0.5 to another side of the contact?
    "rmodif,cid,14,1e5" - thermal contact conductance? in what units?
    Thanks again
  • st2021
    Subscriber
    How do I find these things? Now I have "et,matid,226,11". Documentation is a bit difficult to navigate. This does not really tell me what 226 or 11 is.
    EDIT: found the answer to this question; now have a next one below.
    Thanks



  • st2021
    Subscriber
    Looks like I found it, "Static, Full Harmonic, Full Transient" analysis for SOLID226, link https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v212/en/ans_elem/Hlp_E_SOLID226.html My current issue is that the solid, when rotated via a Body-Ground Joint and a Joint Load with constant velocity, starts to cool down. What is it caused by and how could this be avoided or controlled?
    More quotes from the doc "For example, KEYOPT(1) is set to 11 for a structural-thermal analysis (structural field key + thermal field key = 1 + 10). For a structural-thermal analysis, UX, UY, and TEMP are the DOF labels and force and heat flow are the reaction solution." This does not appear related to the issue.
    Thanks
  • st2021
    Subscriber
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