I use PVDF shock gauges, when they are impacted, I can measure an electrical signal that is actually the charge provided by the piezoelectric effect in the PVDF. It is plugged on a 50 Ohms channel and the capacitance of the Piezo sensor is about 15 pF. I have no problem for monitoring the signal but be sure that the time scale is adapted and the channel is sensitive enough (mV/div).

Dear Arrigoni,

Thank you very much for your answer.

actually, I need to simulate this in Ansys Workbench; but I do not know how do it. Please help me if you have any experience in simulation of piezoelectric harvesters.

Hi, use circu94 element for resistor and give high resistance value. Normally 10 Mohm is suffcient because internal resistance of any voltage measuring device wont be more than 10 Mohm. If you wish give higher resistance, but I dont think any change will there in voltage. One node of circu94 element should be grounded and measure voltage at the other node. 

Hello Deepesh, 

Thank you very much for your response. I know that circu94 should be used for defining resistor.

Actually, I am working in Ansys Workbench and I use command block to define piezoelectric material and boundary conditions. Did you apply command block in your case or you simulate in APDL?

My case study is an unimorph beam which the piezoelectric is batched on the beam top surface.

My question is that where should be considered as ground? the bottom surface of the substrate (beam) or the bottom surface of the piezoelectric?

In the ground, voltage would be zero as a boundary condition. Then, I define a master node on the ground and put zero for the master node. Should be all points on the ground surface have zero value or just put zero for a node on the surface like master node?

Hi,

I'm using APDL.

If PZT is bonded to substrate, PZT bottom surface or top surface of substrate should have same nodes. Am i right?

I have some confusion on why u defined two resistor elements. Then how is PZT elements and resistor interacting? Try this way.

constrain (CP)all the bottom surface nodes of PZT layer to one node of resistor. Make  bc with volt zero. So this is grounded.

Constrain nodes of top surface of PZT to the other node of resistor. measure voltage across this node. I hope this is clear.

Hello, thank you very much for giving answer.

you are right, bottom surface of the piezo is the same with upper surface of substrate. My question is we connect the resistor to bottom of substrate or upper of it(bottom of piezo)? I think that ground surface is the bottom of piezo (up surface of substrate) but in your paper, you connect the resistor to bottom of substrate.

yes, I made a mistake, I need one resistor element as follow commands:

et,20,circu94,0

r,1,RL ! define fixed value RL for the resistor

type,20 $ real,1

e,n_top,n_bot

I tried this and it works, thank you very much

I do not understand how constrain all the nodes on top or bottom surfaces to the one node of resistor, may you explain more?

Best regards,

Hi, 

1. yeah, my picture in article is misleading. It should be bot surface of PZT. but it is understandable that we have to use only PZT layers. I will correct that in future. Thanks.

2. For constraining nodes, simply define resistor nodes and select all nodes on one surface to resistor node using CP as you have done. If your n_top and n_bot are not the nodes on PZT surface (if they are free nodes) that is what i am referring. If u r already doing that. ignore this Thanks.. 

Hi Ali

Can you please send me your basic model of energy harvester to [email protected]. I am new to ANSYS please give some help