piezoelectric shell element

Hello Experts,

I am trying to do modal analysis on user-defined piezoelectric shell element. My eigen value probelm of free vibration is given in the attachment.

I am working on finite element formulation of thermopiezoelectric shell element. i want to incorporate it in Abaqus software as a project work. i would like to know how to add the new element in abaqus.how can i add? Pls do help