General Mechanical

General Mechanical

How to select elements which are above a certain temperature and kill them?

    • Prashanth_Kulkarni
      Subscriber

      Hello,

      I have been trying to simulate electric discharge machining (transient thermal analysis) on a 2D axisymmetric body using ANSYS APDL software. After obtaining a temperature distribution, I now want to kill the elements above the melting temperature in order to obtain a crater. Can anyone guide me on how to proceed further to get the required results? I'm pretty new to ANSYS so any relevant answer or material would be appreciated

      Thank you

    • Surya
      Ansys Employee

      The command NSEL can be used to select the nodes over a particular temperature and the command EKILL can be used to kill those elements. Please refer to this help documentation for the both NSEL - NSEL (ansys.com) and EKILL - EKILL (ansys.com)
      Also refer to this example code where a similar application is executed - Performing EKILL Element Death in Workbench Mechanical | SimuTech (simutechgroup.com)

      Thanks Surya
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    • Erik Kostson
      Ansys Employee
      Hi
      Below is a link that shows how to do this using nsel and esln commands:

      All the best

      Erik
    • Prashanth_Kulkarni
      Subscriber
      thank you for your swift reply I followed a similar procedure to the one you stated in your answer and was able to select the elements above melting temperature using esln. But, when I try to kill the elements using EKILL,ALL., The following error is showing up. Where did I go wrong? This is the code that I used. I just want to mention that I am doing the whole analysis using ANSYS APDL only and I was giving the code input line by line.
      /solu
      *do,time_val,0,1,1e-3
      !!! Apply load
      solve
      nsel,s,temp,,1400,1900
      esln
      ekill,all

      Thank you

    • Erik Kostson
      Ansys Employee
      Hi

      Unfortunately I can not advice and troubleshoot in order to find out why this does not work - perhaps some other users can chime in here.
      What we said is that we need a combination of nsel, esln, and ekill commands to do this.
      As the message says though the nropt,full needs to be specified before solve and ekill.
      All the best
      Erik
    • dinhan0394
      Subscriber
      The Birth and Death require Full Newton-Raphson solutions. You can active the option by adding the command: NROPT,FULL
      NROPT, FULL
      /solu
      *do,time_val,0,1,1e-3
      !!! Apply load
      solve
      nsel,s,temp,,1400,1900
      esln
      ekill,all
    • Prashanth_Kulkarni
      Subscriber
      and thanks to your guidance and input, I am now able to kill the elements
      But, I am facing one problem here. Even though I am using the code
      nsel,s,temp,,1400,10000 !to select the elements above 1400 K
      esln
      to select the elements above the melting point, the elements which are not present in the temperature range are also getting selected. Can you please explain how to tackle this problem?
      As you can see even though I gave a range of 1400 K to 10000K, the elements below 1400K are also getting selected
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