Page 42 - E-Tez Bülteni Mart 2025, SAYI 1

Tez Özeti

This thesis presents a comprehensive study of static, dynamic, and stability analyses of functionally graded sandwich beams (FGSBs) with
porous core resting on a Winkler-Pasternak elastic foundation. The research focuses on the free vibration, buckling, and bending
characteristics of FGSBs with three different core configurations: porous ceramic core, metallic core, and functionally graded (FG) porous
core. A power-law distribution is used to model the gradual variation of material properties across the thickness, considering three distinct
porosity patterns: uniform, symmetric, and asymmetric. A general theoretical formulation is derived from a quasi-3D deformation theory.
The governing equations of motion are obtained using Hamilton’s principle and Lagrange's equations. Analytical models, formulated using
the Navier and Ritz methods, are complemented by a novel three-node higher-order finite element model. Additionally, a novel FGSB
modeling technique is presented using Ansys Mechanical APDL. The accuracy and efficiency of these quasi-3D models are demonstrated
and validated through comparisons with existing literature. The study explores the effects of material property homogenization schemes,
transverse normal deformation, boundary conditions, structural configurations, porosity characteristics, and foundation parameters on
natural frequency, critical buckling, bending, and stress responses. The findings reveal that the introduction of porosity into the core of
FGSBs significantly influences their mechanical behavior, with symmetric porosity configurations resulting in superior performance.
Keywords: FG sandwich beams; Quasi-3D theory; Porosity; Elastic foundation; Statics; Free vibration; Buckling; Navier’s
method; Ritz method; Finite element method; Ansys