Learning Forum

[loant22]

Good day!

 

I am trying to learn the basics on how to simulate a piezoelectric energy harvester where the end result is a graph of voltage created within the piezoelectric body as a reaction to an applied force. I have tried many methods of approach such as Modal with Harmonic Response, Modal with Coupled Field Harmonic and Modal with Static Structural, but none of these have been successful as I have always ran into some error I couldn't work out. Now, after reading through the Help Manual and what it has to offer regarding piezoelectric bodies, I tried Modal with Coupled Field Modal, and for the first time I got to complete the simulations without problems. However, the Help Manual wasn't clear on what exactly the voltage results represent, so I have come here to ask for clarification, because I have a feeling it is still not exactly what I'm looking for; What is the electric voltage result based on, where exactly does it come from in this simulation as in what creates it? It isn't based on an applied force, that's for sure, since that cannot be inputted into Coupled Field Modal, but I would like to know if it's close to that. Thanks a bunch for helping me!

 

Here are a couple screenshots of my setup and settings, as well as one specific voltage simulation result on the piezoelectric body of the assembly to visualize my problem. 

[Erik Kostson]

 

 

 

 

Hi

The absolute values of the deformation/voltages (which are huge as you can see) of the modal analysis mode shape results do not mean anything as these are scaled eigenvectors/modes.

Only the frequency and the over all mode shape is of interest but not as said the exact and absolute magnitude. displacement/voltage values.

Hope that is clear. If not see here for some more discussions:

https://innovationspace.ansys.com/forum/forums/topic/natural-frequencies-anslysis/
https://innovationspace.ansys.com/forum/forums/topic/unrealistically-large-deformation-modal-analysis

I would suggest a course from ais on modal analysis where this also explained.

The displacement/stress results and voltages are of interest and can be looked at, once and when applying a force in a coupled field harmonic analysis.

See also our tutorials on this (coupled field harmonic):

In the help manual for the: Mechanical Technology Showcase: Example Problems Chapter 39: Wire Bonding Ultrasonic Transducer 

Erik

 

 

 

 

[loant22]

Erik,

thank you for your quick reply. Your explanation is clear and I have attempted following the tutorial on Mechanical Technology Showcase. It was helpful in some aspects and I got its results without errors, however the tutorial wasn't clear at times if it was talking about modal analysis or more specifically about coupled field modal analysis, likewise with harmonic response analysis and coupled field harmonic response analysis, so I had to do some quesswork at times, making it hard to say whether the structure of my simulation is correct. Just an overall feedback on the style of writing of the tutorial. I will review the modal analysis course as well, but I doubt it will aid me with my aim to simulate piezoelectric energy harvester directly. Nonetheless I appreciate your reply.

[Erik Kostson]

Hi

Glad it helped.

I agree it has a lot of things in it (static, modal and harmonic), and is an advanced workflow, so it can get a bit confusing perhaps, so thank you for the feedback.

All the best

Erik