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Piezoelectric coupled with a electric circuit for vibration damping
Posted 25 giu 2018, 20:20 GMT-4 Electromagnetics, Piezoelectric Devices, Structural & Acoustics Version 5.3 2 Replies
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Hi, everyone! I am simulating the effect of a shunt circuit on the vibration of a piezoelectric device. Theoretically, with a shunt circuit connected (a resistor and a inductor in serie with the pzt), the vibration of the device will be further damped. However, when I connect a shunt circuit to the two electrodes of the pzt, the vibration amplitude is unchanged. I think the circuit and the pzt is not coupled well and the circuit does not back-affect the pzt module.
The main boundary setup of my model are:
For the PZT module: 1. The PZT is attached to beam that is fixed at one end and a harmonic loading is applied on the other end; 2. the lower face of the PZT is grounded; the upper face is set as Terminal.
For the electric circuit module: 1. ground node is 0; 2. "External I vs.U" is added between 2 and 0 and is connected the Solid Mechanics module and the voltage is the Terminal on the upper face of the PZT. 3. a resistor node is added between 2 and 1; 4. a inductor is added between 1 and 0;
So the question is: 1. will the "electric circuit " module response back to the Solid Mechanics module? 2. will the "electric circuit" module consider the conservation of energy and thus can consume the mechanical energy in the form of joule heating? 3. any comment on this model and any suggestions?
Thank you in advance for any comment and help!!
José Emilio Traver
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Dear José,
The piezo Terminal is essentially an Electrostatics Terminal. It may be the initial conditions for charge and voltage on the Terminal node (Advanced Settings - make sure that Advanced Physics Options are dislplayed) that are inconsistently set. See the attached example of a capacitor with the initial conditions for the electric potential and the Terminal consistently set. Note also that the usage of the External I-Terminal in the circuit allows you to apply the coupling in one single node (with local grounds in the circuit and finite element parts). Note the difference in initial conditions for the Terminal in Electrostatics and Electric Currents, respectively. If the initial conditions are inconsistently set (for example zero Terminal charge), the consistent initialization in the time-dependent solver cannot compensate for that.
-------------------Magnus
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First at all, Thanks Magnus for your response.
I have checked the initial conditions of Terminal node and both are set to zero. I think it is coherent, because at t=0s the beam and pzt are rest. I simulated it again and the resuls were the same. However, if I chage the parameter "Apply reaction term on" from All Physics to Current Physis in Constraint Settings, the results are different regarding to the former. Although they isn't modified If I change some parameter of the circuit in a Frequency Study, but not in a Temporal Study, where the results change. Is this made sense?
Thanks you again.
José Emilio Traver