OICC Press Journal of Solid Mechanics 2008-7683 15 4 2023 09 01 Vibrations of Multi-Layer Beam with Nanocomposite Face Sheets Reinforced with Graphene Platelets and Porous Core 258 273 EN A Mihankhah Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran Zahra Khoddami Maraghi Faculty of Engineering, Mahallat Institute of Higher Education, Mahallat, Iran Ali Ghorbanpour Arani Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran-----Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, Iran Shahriar Niknejad Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran Journal Article 2023 09 01 The current article investigates the free vibrations of a three-layer beam. The middle layer of this structure is selected from porous material. For modeling the porous layer, linear pro-elasticity relationships are applied, while Young's modulus and its density vary along the thickness. The upper and lower layers of the structure are reinforced with graphene nanoplates and can take different configurations as Parabolic, linear, and uniform. In this study, with the help of Halpin-Tsai modified theory, equivalent composite coefficients will be extracted. The equations of motion in three layers are derived with the help of third order shear theory, energy method and Hamilton's Principle. Among the significant results of this article, we can mention the effect of amplifiers in improving the vibration behavior of the beam, the effect of pore pressure and volume fraction of reinforcement on the frequency of vibrations. The results of this research can be applied in marine, aerospace, and civil industries.