Hello, I am simulating piezoelectric stack of AlN that is sandwiched between two electrodes and the sandwich sits on a Si substrate. I remember doing this in version 4 and now I am using v5.5 but for some reason, when I select the solid model to be anisotropic uunder linear elastic material tab, Young's modulus (E) and Poisson's ratio (nu) seems like they are still required as well as relative permittivity. In isotropic material case these are already there and epsilon is not so I understand the requirement for the relative permittivity. However D matrix is there and the solver wats to know E. Why is that?
Thanks,
-Ozan