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Evalutaing piezoelectric performance of multi-layer PVDF wrapped around cylinder

Posted 2025/05/20 15:31 GMT-4 Structural & Acoustics, MEMS & Piezoelectric Devices, Modeling Workflow Version 6.2 0 Replies

Naveed Arang

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Hi all,

I am trying to create a simulation of a dumbbell-shaped piece of aluminum wrapped in multiple layers of piezoelectric PVDF, polyimide insulator, and a single layer of PDMS sealant, in that order. The goal is to see how much voltage the PVDF can generate given a uniform pressure around the outermost layer of PDMS, and in the future evaluate different results for different thicknesses of PVDF, numbers of layers, etc. In real life, this device would use a single sheet of PVDF wrapped around the dumbbell, hence the need for an electrical insulator.

In my first 3 screenshots I have a layer of each material, with each layer attached to the other using the flexible attachment module, to simulate the mechanical contact each film has with each other. I have a rigid attachment of the innermost layer to the dumbbell because, frankly, that is what seems to give me a realistic end result.

The inside layer of the PVDF is the ground, and the outside layer is the floating potential. I have a radial coordinate system defined for the piezoelectric that is in the d33 direction. The ends of the dumbell are fixed as well as the end faces of the film so it doesn't deform outwards, and a boundary load pressure of 5.3 kpa is applied on the outer film.

This single layer simulation gives me results that I feel are reasonable to expect, specifically an even peak to peak voltage. However, in the second simulation with two layers of PVDF and otherwise similar parameters, my peak to peak is uneven. This occurs for any even number of PVDF and insulator layers, but not for odd numbers of layers.

Can I please get a sanity check on my approach to this problem? Should I be using the contact module instead for the film to film interface? I would expect the bulk of the piezoelectric response to be where the bending stress is the most, but that is not happening.

Unfortunately my files are too large to upload so I provided screenshots of results. If google drive links are permissible I can provide that. Thank you very much!

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