Deflection and buckling of a sandwich curve beam with variable cross-section using fifth-order shear deformation theory with FEM: a piezoelectric layer, hierarchical and conventional honeycomb core

This work analyzes the deflection and buckling behavior of a sandwich curve beam with variable cross-section using the fifth-order shear deformation theory (FISDT) with finite element method (FEM). The beam comprises nanocomposite face sheets reinforced with carbon nanotubes (CNTs) and graphene platelets (GPLs), piezoelectric layers. Also, various porous patterns (three types) or two type honeycomb core (hierarchical and conventional) for a sandwich curve beam are investigated. The governing equations are derived from FISDT and converted into their weak form based on FEM application. The stiffness and buckling matrices are subsequently formulated to assess the beam’s deflection and critical buckling load. The normal and shear stresses for a sandwich curve beam along the thickness are obtained and plotted. A 1% augmentation in CNT content reduces the transverse deflection by 42.2% and increases the buckling load by 42.4%. A symmetric porosity distribution results in greater stiffness in comparison of other cases, also, a negative applied voltage enhances the critical buckling load. Increasing the honeycomb angle and aspect ratio enhances transverse displacement. The variation coefficient of the cross-section (α) positively affects buckling resistance, thus, the critical buckling load increases, and vice versa for deflection. Also, the parabolic cross section yielding the lowest critical buckling load. Conversely, augmenting the radius of curvature (R) diminishes the critical buckling load. In honeycomb cores, an increase in the internal hexagonal angle and the ratio of the hexagon’s diameters leads to reduce the stiffness and stability, thus the critical buckling load decreases, while it is vice versa for deflection of a sandwich curve beam. Clamped–clamped supports produce the minimum deflection and the maximum buckling load among boundary conditions. The present work demonstrates that the fifth-order shear deformation theory markedly enhances the precision of buckling predictions for a sandwich curve beam. The suggested model offers significant insights into the design of lightweight, high-stiffness, and multifunctional smart structures for the aerospace, automotive, and marine sectors.