ISOPARAMETRIC MIXED FINITE-ELEMENT FORMULATION OF ORTHOTROPIC CYLINDRICAL-SHELLS

In this research, using the Gateaux differential, an efficient computa tional procedure is presented and a new functional with geometric and dynamic boundary conditions is obtained for orthotropic cylindrical sh ells. A mixed finite element (ORTHO36) is generated which is a conform ing, rectangular (four-noded), isoparametric ''serendipity'' family el ement and has 4 x 9 degrees of freedom. The existence of first order d erivatives in the functional provides the advantage of using linear sh ape functions. The formulation is applicable to orthotropic cylindrica l shells with all kinds of boundary and loading conditions. The accura cy of the ORTHO36 element is verified by applying the method to some t est problems which exist in the literature.