GEOMETRICALLY NONLINEAR-ANALYSIS OF SHELLS BY THE VARIATIONAL APPROACH AND AN EFFICIENT FINITE-ELEMENT FORMULATION

A family of variational principles and a quasi-conforming isoparametri c element model, based on the so-called polar decomposition theorem an d the dyadic notation, are derived for the nonlinear analysis of shell s with arbitrary geometry. The principles include three pairs of funct ionals with three, two or one field(s) of independent variables subjec ted to variation, and with the incremental form of functional Gamma(3) , an eight node shell element model is constructed and used in two num erical examples. Representative numerical results, based on this proce dure, are presented and compared with those found in published literat ure.