Learning Forum

[Mona Yadi]

Hello,

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
et,1,SOLID226,1001
*get,Epz,elem,,count ! Get the number of solid elements

cmsel, S, POS
nsle, S, All
cp,1,volt,all
*get,POS,node,0,num,min ! get master node on bottom electrode

cmsel, S, GND
nsle, S, All
cp,2,volt,all
*get,GND,node,0,num,min ! get master node on top electrode

d,GND,volt,0 ! ground bottom electrode
d,POS,volt,1
fini

/prep7
!
! 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
!
n,1,0,0
n,2,0,1
type,65 $ real, 5
e, 2, 1

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

n,3,1,1/3
n,4,1,2/3

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

fini

[Erik Kostson]

 

 

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 (

 

NUMSTR,NODE,10),

 

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., : https://forum.ansys.com/forums/topic/ansys-2021-workbench-piezoelectric-analysis-add-resistor/)

All the best

Erik

 

 

[Bill Bulat]

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:

*get,NMAX,node,,num,max

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:

n,NMAX+1,xlocation,ylocation,zlocation

n,NMAX+2,xlocation,ylocation,zlocation

By the way, APDL is not case sensitive.

 

Kind regards,

Bill