Techno Press

Steel and Composite Structures   Volume 25, Number 2, October10 2017, pages 141-155
Damping and vibration analysis of viscoelastic curved microbeam reinforced with FG-CNTs resting on viscoelastic medium using strain gradient theory and DQM
Farshid Allahkarami, Mansour Nikkhah-Bahrami and Maryam Ghassabzadeh Saryazdi

Abstract     [Full Text]
    This paper presents an investigation into the magneto-thermo-mechanical vibration and damping of a viscoelastic functionally graded-carbon nanotubes (FG-CNTs)-reinforced curved microbeam based on Timoshenko beam and strain gradient theories. The structure is surrounded by a viscoelastic medium which is simulated with spring, damper and shear elements. The effective temperature-dependent material properties of the CNTs-reinforced composite beam are obtained using the extended rule of mixture. The structure is assumed to be subjected to a longitudinal magnetic field. The governing equations of motion are derived using Hamilton's principle and solved by employing differential quadrature method (DQM). The effect of various parameter like volume percent and distribution type of CNTs, temperature change, magnetic field, boundary conditions, material length scale parameter, central angle, viscoelastic medium and structural damping on the vibration and damping behaviors of the nanocomposite curved microbeam is examined. The results show that with increasing volume percent of CNTs and considering magnetic field, material length scale parameter and viscoelastic medium, the frequency of the system increases and critically damped situation occurs at higher values of damper constant. In addition, the structure with FGX distribution type of CNTs has the highest stiffness. It is also observed that increasing temperature, structural damping and central angle of curved microbeam decreases the frequency of the system.
Key Words
    vibration analysis; FG-CNTs-reinforced composite; curved microbeam; Timoshenko beam; strain gradient theory; magnetic field; viscoelastic medium
(1) Farshid Allahkarami, Mansour Nikkhah-Bahrami:
Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran;
(2) Maryam Ghassabzadeh Saryazdi:
Vehicle Technology Research Institute, Amirkabir University of Technology, Tehran, Iran.

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