Static Behaviour of Functionally Graded Magneto-Electro-Elastic Plates and Beams in Thermal and Hygrothermal Environment

Abstract

This dissertation deals with the investigation of coupled multiphysics response of stepped functionally graded magneto-electro-elastic (SFGMEE) and multiphase MEE beams and plates in the thermal and hygrothermal environment. The influence of pyroeffects on the direct and derived quantities of MEE beams and plates has been investigated. An attempt has been made to evaluate the effect of external moisture and temperature on the static parameters of hygrothermo-magneto-electro-elastic (HTMEE) beams and plates made of adaptive wood encapsulated with piezoelectric material (Barium Titanate-BaTiO3) and magnetostrictive material (Cobalt FerriteCoFe2O4). To this end, three-dimensional finite element (FE) formulation has been derived with the aid of the total potential energy principle and constitutive equations of MEE material considering the temperature and moisture fields. The condensation technique is employed to obtain the nodal values of degrees of freedom such as displacement components, electric potential and magnetic potential. Further, the FE formulation is extended to study the individual and combined effects of thermal, magnetic and electric fields on the static behaviour of SFGMEE plates. The effect of volume fractions, boundary conditions, aspect ratio, stacking sequence and length-towidth ratio on the static response of SFGMEE and multiphase beams and plates has been studied. The numerical evaluation reveals that the different thermal loading profiles exhibit unique effect on the static behaviour of MEE beams and plates. In addition, the significant influence of pyroeffects is noticed for all the forms of thermal loads. The volume fractions of BaTiO3 and CoFe2O4 show a considerable influence on the variation of multiphase MEE beam. Furthermore, a novel FE approach presented to deal with the hygrothermal response of MEE beams and plates suggest that the moisture and temperature fields exhibit a predominant effect on the static parameters. The empirical constants associated with the temperature and moisture dependent elastic stiffness alter the hygrothermal response of MEE beams and plates.iv The comprehensive investigation on the effects of multi-field loads on the characteristic behaviour of SFGMEE plates is carried out using the first order shear deformation theory (FSDT). The results disclose that the predominant influence of the electric and magnetic loads along with the thermal load exhibit a predominant influence on the behaviour of the plates. Finally, the influence of BaTiO3 and CoFe2O4 particle arrangement on the static response of magneto-electro-thermo-elastic (METE) plates has been investigated. The significant forms of particles arrangement such as body-centered cubic, face-centered cubic and simple cube are considered for the analysis. The investigation reveals that the direct (displacements, electric potential and magnetic potential) and derived quantities (stresses, electric displacement, magnetic flux densities) of METE plate predominantly vary with respect to the particle arrangement.