FINITE ELEMENT MODEL FOR NONLINEAR ANALYSIS OF FUNCTIONALLY GRADED PLATE/SHELL STRUCTURES
José Simões Moita1; Aurélio Lima Araújo1; Cristovão Mota Soares1; José Herskovits2
1 IDMEC- Instituto Superior Tecnico, Universidade de Lisboa; 2 COPPE-UFRJ, Universidade Federal do Rio de Janeiro
doi:10.20906/CPS/CILAMCE2015-0030
Resumo
A finite element model for linear buckling and geometric nonlinear analyses of general FGM plate-shell type structures is presented. Typical FGM plate-shell type structures are made of Functionally Graded Materials whose are characterized by a continuous variation of the material properties over the thickness direction by mixing two different materials, metal and ceramic, and are widely used in aircraft, space vehicles, reactor vessels, and other engineering applications. In FGM plate-shell structures the smooth and continuous variation of the properties from one surface to the other eliminates abrupt changes in the stress and displacement distributions, in contrast with the structures made of composite materials where may occur abrupt changes at the interface between two different materials. Geometric nonlinearity plays a significant role in the behavior of a plate or shell, especially when it undergoes large deformations. This is the main reason to the present work, which includes not only the analysis of the nonlinear behavior, but also the linear buckling responses of this type of structures. Using the Newton-Raphson incremental-iterative method in conjugation with the updated Lagrangian formulation, the incremental equilibrium path is obtained, and in case of snap-through occurrence the automatic arc-length method is considered. The finite element is a non-conforming triangular flat plate/shell element with 24 degrees of freedom for the generalized displacements. The solutions of some illustrative plate/shell examples are presented and compared with numerical alternative models.
Palavras-chave: Finite Element; Functionally Graded Materials; Non-Linear Analysis