# I Damping coefficient in RLC model (piezoelectric transducer)

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1. Dec 7, 2016

### piezo_student

Hello!

I am a university student working on a project regarding a piezoelectric patch transducer, and RLC modelling of said transducer.

Edit: After reading the rule post i think i should clarify this is not coursework homework, this is a thesis project.

The short version of my question is how to find the damping coefficient. I am fairly new to this field, and this question keeps puzzling me. The transducer that i have is this one and with this datasheet i should have everything i need to do an equivalent RLC modelling. The modeling is based on a second order spring-mass-damper system with single degree of freedom, i can't link directly to the contents of the book i'm using but it's very much like the model described here.

Now, i have found the stiffness through the formula for axial stiffness under this section on wikipedia, the youngs modulus multiplied by cross sectional area divided by length. (The youngs modulus of the complete transducer is not in the datasheet but i found it on a different section of the manufacturers websites so i can trust that)

I have the mass, which is given in the datasheet.

Now all i need is the damping coefficient, and i've looked around and i think i understand what the damping coefficient is, i just don't have any idea on how to calculate it or measure it. ANY input on this would be helpful, what would be the easiest and most accurate way for me to find this coefficient? I have lab equipment to do measurements if that's what it requires.

Edit: I should also add, that i have a material coefficient table of the active material in the transducer, which includes a mechanical quality factor Qm, maybe this is key?

Apologies if i'm in the wrong forum section, i'm new here. If you know a better forum for my question please inform me of this it would be much appreciated.

Thanks in advance.

Regards

Last edited: Dec 7, 2016
2. Dec 7, 2016

3. Dec 8, 2016

### piezo_student

Thanks Tom.G, after some research i realized i've been going in circles, when it really is that simple.

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