Voltage Coupling and Voltage Frequency Response Problems.

Hello to all,

I am trying to perform an energy harvesting analysis on a structure with 4 piezolecetric patches. I am using ACT Piezo&MEMS Extension. However, I come up with two major errors.

1) I have defined 8 (4x2) voltage couplings for top and bottom surfaces of the patches. When I conduct harmonic analysis, I receive errors such as "Node 2507 direction VOLT included in coupled sets 5 and 1". What is the reason of this error? and how can I resolve this problem?

2) I suppressed 7 voltage couplings and kept just one coupling (bottom face of the piezo), and run the harmonic analysis. Now, the solver worked, but this time when I want to plot the voltage frequency response for the remaining piezo, I got this following error.

"The user defined result might not be calculated successfully wholly or in some areas. There are some elements (or nodes) which do not contain data for the expression in: 133HARMONIC = VOLT

Note that the result data may not be contained in the result file or may not be applicable to some element types. Also note that the solver module can create elements, such as surface effect or interface elements, whose results cannot currently be scoped in a contour display."

If you help me about these problems, I will appreciate.



  • HuiLiuHuiLiu Posts: 98Ansys Employee

    What version of Ansys Mechanical and the ACT are you using? You need to make sure the ACT version is compatible with the Mechanical version. You can check you solve.out file, see what element types have been generated to make sure piezoelectric definitions are correctly done through the ACT (solid226/227 element types).

    For the postprocessing error, you can try insert a user defined result and set it to VOLT. See if this helps. Or insert a command object to print/plot the volt dof.

  • IngeniatoremIngeniatorem Posts: 2Member

    Hi Huiliu.

    Thank you for the response. I am using ANSYS 2020 and Piezo&MEMS Extension. It is compatible with the edition used since I performed an analysis for a piezoelectric actuator before. In that analysis, there was just one piezo patch. Right now, I am trying to conduct an energy harvesting analysis with 4 piezoelectric sensors, thus, obtain the voltage output and plot the voltage frequency responses for each piezoelectric sensor. For this reason, I define voltage couplings for each face of the piezoelectric sensors and apply zero voltage (ground) for the top faces. However, I receive the voltage coupling errors as mentioned above. When I just keep one voltage coupling and suppress the others, the analysis runs. I do not understand why it happens. As you said, I checked the element types from the solve file. It seems all right.

    Secondly, when I run the analysis with just one voltage coupling for one piezo, I come up with the errors for plotting the voltage responses, as mentioned above. Can it be due to the polarization of the piezoelectric sensor??

    Thank you in advance

    1    160 SOLID226   0.078  0.000488

    2    192 SOLID226   0.062  0.000326

    3    160 SOLID226   0.125  0.000781

    4    160 SOLID226   0.078  0.000488

    5   45876 SOLID187   3.250  0.000071

    6    361 CONTA174   0.000  0.000000

    8    207 CONTA174   0.016  0.000075

    10    337 CONTA174   0.000  0.000000

    12    349 CONTA174   0.047  0.000134

  • bugrrasenbugrrasen Posts: 11Member

    hello, I get similar errors, my biggest problem is that the results change when I change the mesh, I could not get a permanent solution. Do you know the problem of this? To work and discuss together, you can write to me by e-mail bugrrasen@gmail.com

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