How to validate voltage from a modeled piezoelectric with theoretical formula?

    • safiana

      Hi everyone,

      I am modeling a piezoelectric disk in ANSYS APDL under 50N force. The disk has 4.7 mm diameter, and 0.25 mm thickness. Based on the website of AmericanPiezo, there is a calculator in their website that we can calculate static voltage by formula. So, for this 50N load, the output voltage has to be 17.86 V.

    • Bill Bulat
      Ansys Employee
      Hello This might not be exactly what you asked for, but I added some post processing APDL to your input to establish results self-consistency. It uses equation 10-51 (image below) to evaluate the expected z component of stress (which should of course equal your applied pressure) given the calculated x, y, and z component strains, the calculated z component of electric field (the calculated x and y components are ~0), and the supplied elastic stiffness and piezoelectric matrices (which can be listed using TBLIST,ALL):
      The z component stressreturned by the APDL expression at the bottom of attached test01.txt very nearly equals your applied pressure. The calculated voltage is ~19.2 V... sorry, I haven't made any effort to investigate the discrepancy between this value and your expected value of 10 V.
      Perhaps more importantly, I changed the structural displacement constraint on the bottom of the disk (it was over-constrained). You want to provide only enough displacement constraints to prevent rigid body motion when your objective is to compare FEA results to idealized theoretical expectations.
      I hope this helps!
      Best regards Bill
    • safiana
      Dear Bill Thank you very much for your informative response. Could I ask what you mean by "test01.txt"? Did you attach any file to this discussion?
      Best Ali
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