Discussion Forum

Hi

I do not really understand which one, can you at least take a "snip/capture" of your creen and upload that so we can easier understand which "coupling" matrix you need.
I find it easier to understand if you add the physics tag name ie PZD, FSI or whatever you are using.

The best is anyhow to upload the model, but I understant too that not all models are to be publised like that on the net, then its often better to make the issue "generic" showing the problem on something simple, but that does not give enough info for us such to keep your model "confidential"

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Good luck
Ivar

Thank You very mUch Ivar for replying. I am sorry you are right- I should hve explained better.
I am using the PZD physics to analyse my system- which is one rectangular block of PZT5H and another block of water just adjacent to the PZT5H. Now when I select the materials- because it is PZD - the properties of water show a user input for "coupling matrix" (as you see in the attachment jpeg). So I dont know what the is the significance of the coupling matrix and i cannot find the specific values. If i put a {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} matrix - what will it mean.

I am not sure if I am clear now. but feel free to ask again...I will my best.

Thanks,
Megha

Hi

I am new to the COMSOL(4.4) and working in structural mechanics (Piezoelecctric Devices PZD).
I am trying to use the material Silicon Nitride (Si3N4) [ under -Add Materials -MEMS- Insulators- Si3N4].
I am having trouble with the values - Elasticity matrix, Coupling Matrix & relative Permittivity of Si3N4.
I am attaching the print screen of that window.

Please let me know the values or let me know the link where I can find them as I searched a lot but I am unable to find the values of these parameters.

Thanks

Anurag

it will be highly appreciated if anyone help to solve the marks point in the attach photo, I am looking for the 1. coupling matrix, elasticity matrix, relative permitivity for silicon
2.coupling matrix, elasticity matrix, relative permitivity for tungsten.

I am using COMSOL 5 using piezoelectric device.

Silicon and tungsten are pure metals (not compound ones) and hence not piezoelectric.

I am facing the same problem with Elasticity matrix, coupling Matrix and relative permittivity. Can you please hep me if you found any method to resolve the problem.

This issue seems to come up often. A piezoelectric material is one where the electrical and mechanical domains are coupled (through the coupling matrix!). Ordinary non-piezo materials do not have that coupling. You need to make these materials linear elastic materials.

If you look at the shear bender example you will see how these settings are done.

D.W. Greve
DWGreve Consulting