Discussion Forum

Hi Lucia,

We have a similar issue with the piezoelectric parameters (i.e. stiffness/coupling /permittivity matrices) required for the piezo-ceramic we are currently using, Pz26. Luckily the manufacturer (www.ferroperm.com) supplies a 'standard' set and an 'FEM' set of piezo parameters. In terms of matching a measured impedance curve with a COMSOL modelled curve, we have found that using the 'standard' set of parameters we can get COMSOL to accurately model the first lateral mode (say, 200 kHz), but no higher order modes. Using the 'FEM' set we can reasonably model the fundamental thickness mode (say, 1100 kHz). We have generated our own set of parameters to model a 4 MHz thickness mode.

What I am trying to say is that you may need to generate a set of piezoelectric parameters for the frequency range of interest for your particular PVDF application. A paper with a good 'recipe' for determining the piezoelectric parameters is Materials Letters 59(2005) 640-643., "Elastic, dielectric, and piezo characterization of..." by J. Peng et al.

Regards,
S Moss

Lucia Seminara,
I am doing modelling related with piezo polymer-ceramic composite , but i am unable to give the coupling and elastisity matrix for , polymer and composite , if you solved yur problem ,can you kindly help me

thanks in advance
harikrishnan c

Density 1780
Elastic Matrix (cE unit is Pa): {10^12/39.5, -10^12/10.2, 10^12/42, -10^12/25.4, -10^12/19.5, 10^12/99.9, 0, 0, 0, 10^12/1.82, 0, 0, 0, 0, 10^12/1.69, 0, 0, 0, 0, 0, 10^12/1.43}

Coupling Matrix (eES unit is C/m2): {0, 0, 23*3/1000, 0, 0, 23*3/1000, 0, 0, -33*3/1000, 0, -23*3/1000, 0, -27*3/1000, 0, 0, 0, 0, 0}

Relative Permittivity (no unit): 12

Can you please kindly mark all the individual components of the elastic matrix (cE unit is Pa) (6*6).

Hi

Please find the answer in attached file. To get more information, I recommend to visit this link as well:
www.comsol.com/community/forums/general/thread/27159/

Thanks a lot. I really appreciate your help to answer my queries.

When i am putting the matrix element of Elastic Matrix (cE unit is Pa) and Coupling Matrix (e unit C/m^2) in stress charge form in material contents section, it turns yellow color and showing "inconsistent unit". The used matrix elements are given below.

Elastic Matrix (cE unit is Pa): {10^12/39.5[Pa],-10^12/10.2[Pa],-10^12/25.4[Pa],0[Pa],0[Pa],0[Pa],-10^12/10.2[Pa],10^12/42[Pa],-10^12/19.5[Pa],0[Pa], 0[Pa],0[Pa],-10^12/25.4[Pa],-10^12/19.5[Pa],10^12/99.9[Pa],0[Pa],0[Pa],0[Pa],0[Pa], 0[Pa],0[Pa],10^12/1.82[Pa],0[Pa],0[Pa],0[Pa],0[Pa],0[Pa],0[Pa],10^12/1.69[Pa],0[Pa],0[Pa], 0[Pa],0[Pa],0[Pa],0[Pa],10^12/1.43[Pa]}

Coupling Matrix (e): {0[C/m^2], 0[C/m^2], 23*3/1000[C/m^2], 0[C/m^2], 0[C/m^2], 23*3/1000[C/m^2], 0[C/m^2], 0[C/m^2], -33*3/1000[C/m^2], 0[C/m^2], -23*3/1000[C/m^2], 0[C/m^2], -27*3/1000[C/m^2], 0[C/m^2], 0[C/m^2], 0[C/m^2], 0[C/m^2], 0[C/m^2]

It will be a pleasure if you kindly help me to overcome this difficulty.

There is no need to put units as mentioned in previous comments