General Mechanical

General Mechanical

Variable thermal contact conductance within the same contact region

    • henriquegpo
      Subscriber

      Hi everyone,

      This is an extrapolation of an old post, in which we discussed how to extract contact pressure information.

      So now I have a model in which I clamp 2 parts together by applying a pressure in specific areas. From that model, I can get the contact pressure values for the contacting region, just like the picture below:

      I have also experimental data that allows me to correlate the contact pressure with the thermal conductance, and I would like to use it as an input to my thermal analysis, but I am not quite sure how to do it.

      So my question is: is there a way to input different thermal contact conductance values for different nodes/elements within the same contact region?
      The only workaround I thought so far was delimiting several smaller contact areas along the whole region, and giving them an average value for thermal conductance, but this seems quite tedious and not flexible at all.
      I am guessing that maybe via scripting/APDL programming this should be possible, but unfortunately I have no experience at all with that. I am willing to dive into that, but first I would like to hear from you if this is indeed possible or if there is another way of doing it.

      Cheers,
      Henrique

    • John Doyle
      Ansys Employee

      You can define TCC as a tabular function of contact pressure via APDL commands.  Below is an old example.  In your case, you would insert these commands in a command object under the contact pair of interest.  Also, the first field of the RMODIF command should refer to "cid" for the contact pair real set number, instead of "2" in this example.  Please refer also to *DIM and RMODIF command in MAPDL Command Reference manual for more details on proper syntax.  It would also be good to refer to the MAPDL Elements Reference Manual for CONTA174 (Table 174.1 and related links) for more background on defining the TCC real constant.

       

    • henriquegpo
      Subscriber

      Hello John,

      Thank you very much for your answer and sorry for the very long delay.

      I went through all the documentation you suggested, and now I have a better feeling on how the commands work and how to set it up properly.
      I am now struggling on what seems to be a much easier step, and would like to ask again for your help.

      So, what I want is to perform a Statict Structural, get the contact pressure results and transfer it to the Steady State Thermal, where the correlation between TCC and pressure would then be used.
      So my question is, how to transfer the loaded/deformed results with the pressure info to the Thermal analysis? I've tried importing the results file to a "imported load" under the Thermal, but it didn't seem to work.

      Could anybody please give me a hint here? Thanks!

    • John Doyle
      Ansys Employee

      I should have also mentioned, you need to run this as a coupled physics (thermal-structural) simulation.  What you are describing cannot be simulated as a pure thermal problem.

    • henriquegpo
      Subscriber

      Yes, I tried to do that, but without success.
      Unfortunately I can only manage to transfer Thermal solution to Structural setup, not the other way around, which is what I was looking for (Structural solution to Thermal setup).

      Could you please describe how I should do it? I spent the last couple of days trying to figure that out, but failed.

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