## E. Analysis of a Piezoelectric Structure Subjected to a Prescribed Displacement or a Prescribed Electrical Potential (STA4)

In this analysis, the matrix equation to solve is identicalto that of STA2:

The user must provide the prescribed displacements and/or the prescribed electrical potentials on given nodes. The code computes the displacement field U and the electrical potential F over the entire structure. It is essential that the boundary conditions eliminaterigid body modes and ensure the uniqueness of the electrical potential (atleast one potential degree-of-freedom must be set to zero). Only one loadingcase can be solved at a time. Taking internal losses into account does notmake physical sense in this analysis and thus is not possible. Magnetostrictivestructures may also be treated by this analysis.

Displacements are prescribed using the EXCITATIONS entry. The matrices are assembled and stored to file by columns. Gaussianalgorithms are used to solve the problem, in single or double precision. It isalso possible to apply forces (STA2) and prescribedisplacements and/or prescribe electrical potentials (STA4)at the same time.