General Mechanical

General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

Piezo-Circuit, how to add the APDL code in work bench

    • Mona Yadi


      I hope you all are fine.

      I took a long time to connect the equivalent circuit of the piezo material (Quartz) to its electrodes (attached on both sides of the quartz), gave it sine voltage, and did a harmonic analysis to see the amplitude of piezo oscillation in the specific range of frequency. I added the CAD data directly to the workbench and added the APDL commands (attached) to the modal analysis (added before the harmonic analysis). Based on the errors I receive " Element 18590 does not have all of its required nodes defined.  The E command is aborted" I am guessing that the problem is with nodes and elements that I introduced. It would be really appreciated if you can help me with this issue.

      I attached the equivalent circuit and the APDL codes, Thanks in advance for your help.


      cmsel, S, Base
      nsle, S, All
      *get,Epz,elem,,count ! Get the number of solid elements

      cmsel, S, POS
      nsle, S, All
      *get,POS,node,0,num,min ! get master node on bottom electrode

      cmsel, S, GND
      nsle, S, All
      *get,GND,node,0,num,min ! get master node on top electrode

      d,GND,volt,0 ! ground bottom electrode

      ! Element types
      et,62,CIRCU94,0 ! R1
      et,63,CIRCU94,2 ! C1
      et,64,CIRCU94,1 ! L1
      et,65,CIRCU94,2 ! C0
      et,66,CIRCU94,4 ! C0
      ! Real constants

      Vmax = 1
      R1 = 22439.55
      L1 = 6405.34626
      C1 = 3.69e-14
      C0 = 1.82e-12
      r,1, Vmax
      r,2, R1 
      r,3, L1 
      r,4, C1
      r,5, C0

      ! Nodes and elements
      type,65 $ real, 5
      e, 2, 1

      type,66 $ real, 1
      e, 1, 2 ! Voltage source 
      e, POS, GND ! Voltage source feeding 


      type,62 $ real, 2 
      e, 1, 3
      type,64 $ real, 3
      e, 3, 4
      type,63 $ real, 4
      e, 4, 2


    • Erik Kostson
      Ansys Employee



      Yes, the nodes 1,2,3,4 allready exists in the workbench mesh/model so can not be used again (find the last node number and add 1 and use that in the new nodes).

      You can see in VM237 how to use circu94 with solid226 piezo – in there you will see that he pzt starts from node10 (




      then it is ok to define N,1 and so on since these nodes do not exist.

      Also look for posts in the forum (e.g., :

      All the best




    • Bill Bulat
      Ansys Employee

      As an alternative to Erik's suggestion, you can interrogate the MAPDL database for the highest numbered node that exists in the model. Let's call it NMAX. This command:


      will define parameter NMAX and set its value to the highest numbered node in the model. You can then create additional nodes to construct the CIRCU94 elements:



      By the way, APDL is not case sensitive.


      Kind regards,


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