Vibration Measuring

[bchetank]

Hi,

Myself a research scholar from India. Basically I am Mechanical Engineer. I am currently carrying out research work on PVDF films. I need to measure vibration on a cantilever beam using PZT patches. I am mounting PZT on beam & I need to measure vibration coming out. So my professor suggested me to check with your software i.e. Labview. Can you send me some info regarding the same.

thanks in advance Chetan

[Henrik_Volkers]

The PZT will create a charge q when a force F is applied. So if you have an acceleration a,  F=ma, where m is the an additional (seismic) mass or the mass of the PZT itself.

This charge q together with the capacity of the PZT (and cable) results in a voltage you can measure. (Just hook it up to a scope and have a look)

To reduce the influence of the parasitic capacities you can build (or use a ready build)  a charge amplifier (CA). The CA will try to keep the voltage at the PZT at zero by creating the same amount of negative charge. He does that with a (FET) OP with a small capacitor in the feedback. The output is again a voltage (low impedance) the can be measured with a DAQ and LabVIEW. The benefit is, that parasitic (cable) capacities have nearly no effect to your measurement.

What DAQ do you can use?

What is frequency range you want to measure?