Nonlinear finite element modeling and analysis of coupled multi-physics smart composite structures

In this dissertation descriptions and derivations of a thermodynamically consistent fully coupled thermopiezomechanical finite rotation shell element and a magnetoelectroelastic (MEE) shell element are presented. Full geometrically nonlinear strain-displacement relations and finite rotations are considered in the framework of FOSD hypothesis. The four node thermopiezomechanical shell element (FOSD FRT) has 5 mechanical DOFs, 3 electrical DOFs and 4 thermal DOFs per node. The thermopiezomechanical shell element is developed to deal with problems of isotropic, FGM and composite laminated structures. Various numerical examples are studied which range from simple single field mechanical problems to complex multi-field problems. For comparison purposes, numerical simulations are performed for certain examples with simplified nonlinear theories like refined von Kármán type (FOSD RVK), moderate rotation theory (MRT) models, and using the commercial FE software Abaqus. Additionally, the presented results are compared with those available in literature as far as possible. In the later part of this thesis, the magnetoelectroelastic shell finite element is developed to deal with static analysis of multilayered composite plates/shells integrated with fully coupled MEE layers. The electric and magnetic potentials have been assumed to vary quadratically over the crosssection of the MEE layer. It is noteworthy to mention that no literature is available concerned with the full geometrically nonlinear 2D-shell element to investigate laminated composite shells integrated with fully coupled MEE layers.