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In this article, theoretical modeling and vibration characteristics of a spinning double-blade beam assembly restricted by elastic supports are studied. Graphene nanoplatelet (GPL) reinforcement and porous foamed metal matrix are adopted to make up the assembly structure. Due to the nonuniformity of the porosity and graphene nanofillers, the material properties of the attached blades and beam are considered to change along the blade thickness and beam radius, respectively. They are obtained via the rule of mixture, the open-cell scheme and the Halpin-Tsai micromechanics model. These attached blades and beam are modeled in accordance with the Euler-Bernoulli beam theory and the Rayleigh beam theory, respectively. Via employing the Lagrange's equation, the equations of motion of the double-blade beam are derived. Then, the natural frequencies of the spinning nanocomposite double-blade beam are calculated by the substructure modal synthesis method and the assumed modes method. A detailed parameter analysis is performed to study the influences of dimension, distribution pattern and weight fraction of GPLs, distribution and coefficient of porosity, length and location of the blades, stiffness and location of supports, and spinning speed on the mechanical behaviors of the double-blade beam assembly. [ABSTRACT FROM AUTHOR]

• A coupled model for a rotating pre-twisted blade-shaft system is established for the first time. • Equations of motion governing the coupled vibration of FG-GPLRC blade-shaft system are derived. • Distribution pattern, weight fraction and geometry parameter of GPLs for improved free vibration behavior of the system are discussed and identified. • Parameters of GPLs for improved free vibration behavior are discussed and identified. • Effects of rotating speed and geometrical parameters of the shaft and blade on free vibration performance are investigated. The free vibration of a rotating functionally graded (FG) pre-twisted blade-shaft assembly reinforced with graphene nanoplatelets (GPLs) is analytically investigated based on the coupled model proposed in this paper. The effective material properties of the blade and shaft are assumed to vary continuously along their thickness and radius directions, respectively, and are determined by Halpin-Tsai micromechanics model and the rule of mixture. Within the framework of the Rayleigh beam theory and Euler-Bernoulli beam theory, the governing equations of motion are derived by using Lagrange's equation. The substructure synthesis method and assumed modes method are utilized to determine the natural frequencies of the system. A comprehensive parametric study is conducted to examine the effects of GPL weight fraction, distribution pattern, geometry and dimensions as well as the blade length, location and pre-twist angle, the shaft length and rotating speed on the natural frequencies. The research findings shed an important light on the design of novel graphene reinforced blade-shaft system for remarkably improved dynamic performance. [ABSTRACT FROM AUTHOR]