Learning Forum

[MCK_Pandaleon]

Hello!

I am having issues with solution parameters on ANSYS Workbench 2020 r2. All seems fine until I want to solve.

I want to visualise both total and directional deformations as well as the voltage applied on the piezo-eletric ceramic that I am studying. I am unable to solve because I have to input the maximum, minimum and average deformation and when they occur but I am unable to input anything in those specific areas.

I encounter this issue with transient and static structural analysis and also with modal+harmonic responses.

Thanks in advance!

[ErKo]

Hi

Can you show some images of the errors/issues you are having so we can try and help - also explain a bit more in detail.

Thanks

Erik

[MCK_Pandaleon]

I am studying a simplified transducer with only the piezoelectric ceramic and the coupling module on top. The voltage applied is a slot signal that goes from -100V to 100V at a frequency of 200kHz (which is supposed to be the driving frequency).
I will first launch modal analysis to then visualise total deformations for different resonance modes, but the results I get don't make much sense : the piezo is absolutely not deformed and the coupling module seem to be too deformed.
This the result for one of the modes, when I create them from the results of the modal analysis, which are here :


When I add the backing module around this first part the results are even worse :
The proportions of the deformation are simply impossible.
As for the Static and transient structural analysis I get this issue :
I am supposed to input values in the places highlighted in red but I cannot input anything.
I also get a warning because I am using multiple dimension analysis even if all the analysis are set on the same dimension setting.
For the commands I am not sure of the one used for the transient and static analysis, but the one used for the modal and harmonic responses is :
'd, positive, 100
d, negative, 0 '

[ErKo]

Hi

Just run a full harmonic response no need for modal - the results you see are strange because the nonpiezo material is softer so it behaves funny like this.

So just run the full harmonic response and excite your piezo - plot the displacements and deformation of the piezo only (so scope results to that part only) and see that it behaves as expected.

Erik

[MCK_Pandaleon]

This does work , but I still have an issue with the command of the transient and static structural analysis.
I want to impose a slot voltage that varies from +100V to -100V at a frequency of 200kHz. How do I do this?
The electrodes are named selections (positive and negative), I thought of putting a time frequency table in place but I haven't managed to do so. Therefore, the simulation doesn't work well.

[ErKo]

That is good - piezo are normally done in freq. domain using harmonic response.

For static use just d,exc,volt,100, and for transient, use a table called for instance voltexcite shown below (that varies with time) instead of a constant:
like this:
/PREP7
CMSEL,S,EXC,NODE
CP,NEXT,VOLT,ALL
ALLSEL,ALL
CMSEL,S,GROUND,NODE
CP,NEXT,VOLT,ALL
ALLSEL,ALL

/SOLU
KBC,1
*DIM,tbexc,TABLE,4,,,TIME
tbexc(1,0) = 0,0.0000011,0.0000022,0.000002225
tbexc(1,1) = 0, 100,0,0
*DIM,voltexcite,TABLE,31,1,1,TIME ! Time values
voltexcite(1,0,1) = 0.
voltexcite(2,0,1) = 2.5e-007
voltexcite(3,0,1) = 2.25e-006
voltexcite(4,0,1) = 2.5e-006
voltexcite(5,0,1) = 2.75e-006
voltexcite(6,0,1) = 4.75e-006
voltexcite(7,0,1) = 5.e-006
voltexcite(8,0,1) = 5.25e-006
voltexcite(9,0,1) = 7.25e-006
voltexcite(10,0,1) = 7.5e-006
voltexcite(11,0,1) = 7.75e-006
voltexcite(12,0,1) = 9.75e-006
voltexcite(13,0,1) = 1.e-005
voltexcite(14,0,1) = 1.025e-005
voltexcite(15,0,1) = 1.225e-005
voltexcite(16,0,1) = 1.25e-005
voltexcite(17,0,1) = 1.275e-005
voltexcite(18,0,1) = 1.475e-005
voltexcite(19,0,1) = 1.5e-005
voltexcite(20,0,1) = 1.525e-005
voltexcite(21,0,1) = 1.725e-005
voltexcite(22,0,1) = 1.75e-005
voltexcite(23,0,1) = 1.775e-005
voltexcite(24,0,1) = 1.975e-005
voltexcite(25,0,1) = 2.e-005
voltexcite(26,0,1) = 2.025e-005
voltexcite(27,0,1) = 2.225e-005
voltexcite(28,0,1) = 2.25e-005
voltexcite(29,0,1) = 2.275e-005
voltexcite(30,0,1) = 2.475e-005
voltexcite(31,0,1) = 2.5e-005
! Load values
voltexcite(1,1,1) = 0.
voltexcite(2,1,1) = 100.
voltexcite(3,1,1) = 100.
voltexcite(4,1,1) = 0.
voltexcite(5,1,1) = -100.
voltexcite(6,1,1) = -100.
voltexcite(7,1,1) = 0.
voltexcite(8,1,1) = 100.
voltexcite(9,1,1) = 100.
voltexcite(10,1,1) = 0.
voltexcite(11,1,1) = -100.
voltexcite(12,1,1) = -100.
voltexcite(13,1,1) = 0.
voltexcite(14,1,1) = 100.
voltexcite(15,1,1) = 100.
voltexcite(16,1,1) = 0.
voltexcite(17,1,1) = -100.
voltexcite(18,1,1) = -100.
voltexcite(19,1,1) = 0.
voltexcite(20,1,1) = 100.
voltexcite(21,1,1) = 100.
voltexcite(22,1,1) = 0.
voltexcite(23,1,1) = -100.
voltexcite(24,1,1) = -100.
voltexcite(25,1,1) = 0.
voltexcite(26,1,1) = 100.
voltexcite(27,1,1) = 100.
voltexcite(28,1,1) = 0.
voltexcite(29,1,1) = -100.
voltexcite(30,1,1) = -100.
voltexcite(31,1,1) = 0.

D,EXC,VOLT,%voltexcite%
D,GROUND,VOLT,0