Adding the Kanda factor for Piezoresistive pressure sensors

Hello,

I am working on a pressure sensor simulation.

How to define non-linearity of materials?

I noticed that checking the box of non linear geometry in the study step gives sort of non linearity on both deflection and output. Does anyone knows what does it add/edit in the material properties?


Can someone help how can I include the kanda factor in my Piezoressitivity matrix?

Thanks,
Mohamed