FINITE-ELEMENT FORMULATION BY PARAMETRIZED HYBRID VARIATIONAL-PRINCIPLES - VARIABLE STIFFNESS AND REMOVAL OF LOCKING

In this paper, a new one-parameter hybrid functional is obtained as a special case of Felippa and Militello's parametrized variational princ iples. The functional contains stress, strain and compatible displacem ent as the primary fields. It will be proved that some of the existing variable stiffness formulations fall into the framework of the new fu nctional. Novel applications of the functional are also suggested, mai nly for removal of locking. Solid element, destabilized 8-node and sta bilized 9-plate elements are designed. All of them can handle thin pla te/shell analysis. In particular, a prominent method is devised for co nstructing stabilization vectors. The vectors are explicit linear func tions of the nodal coordinates and can be implemented without resortin g to Gram Schmidt orthogonalization or numerical integration. Results of the new elements in popular benchmark tests are encouraging.