Based on the mechanical and electrical equilibrium equations of piezoe
lectric materials, the minimum potential theory is presented by using
the virtual work principle in this paper. A finite element method (FEM
) formulation accounting for the electro-mechanical coupling effect of
piezoelectric materials is given. Some problems in the numerical simu
lation are discussed and the extreme illness of the stiffness matrix i
s overcome by the dimension changing method. As a simple application,
the response of an elliptical cavity in infinite media of piezoelectri
c materials is analyzed. Such a geometry leads to stress and electric
field concentrations. (C) 1997 Elsevier Science B.V.