OICC Press Journal of Solid Mechanics 2008-7683 18 1 2026 03 31 Vibration Analysis of a Sandwich Microbeam with Functionally Graded Porous Core and CNT Face Sheets, Considering Surface Effects 10.57647/jsm.2026.1801.03 EN Arezo Havazadeh Ali Ghorbanpour Arani https://orcid.org/0000-0001-5754-0786 Hamed Khani Arani K.N.Toosi University of Technology https://orcid.org/0000-0001-8169-0418 Journal Article 2026 03 31 In this research, the vibration behavior of a sandwich microbeam with a graded porous core and carbon nanotube (CNT)-reinforced surfaces resting on a Visco-Pasternak foundation and taking surface effects into account is investigated. Moreover, to achieve accurate results, surface phenomena such as surface elasticity and residual stresses are incorporated by using the Mori-Tanaka homogenization method and Gurtin-Murdoch model, while the porous core's properties are characterized by a symmetric porosity distribution model. The governing equations are derived based on the third-order shear deformation theory (Reddy beam theory) and Hamilton’s principle. These equations are solved using the generalized differential quadrature method, accompanied by a detailed numerical study employing the modified couple stress theory (MCST). A parametric study is presented to investigate the impact of various characteristics, including the geometric properties porosity and distribution pattern of pores, mass fraction, type and distribution pattern of CNTs, length scale parameter, foundation parameters, and boundary conditions. Results reveal that increasing both the core porosity ratio and mass fraction of CNTs leads to an increase in the microbeam's natural frequencies and damping. The presented results can be used in the optimal design and analysis of the lightweight and robust structures in aerospace and advanced engineering applications.