Coupled variational principles of piezoelectricity

A family of generalized variational principles of piezoelectricity carl be obtained straightforwardly from the field equations and boundary conditions via the semi-inverse method of establishing variational principles propose d by He without using Lagrange multipliers. The present theory provides a q uite straightforward tool to search for various variational principles for physical problems. This paper aims at providing a more complete theoretical basis for the finite element applications and other direct variational met hods such as Ritz's, Trefftz's and Kantorovitch's methods. (C) 2001 Elsevie r Science Ltd. All rights reserved.