Nonlinear Vibration Analysis of Axially Functionally Graded Microbeams Based on Nonlinear Elastic Foundation Using Modified Couple Stress Theory

  • Mehdi Alimoradzadeh
    Affiliation

    Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran, P. O. B. 8514143131

  • Mehdi Salehi
    Affiliation

    Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran, P. O. B. 8514143131

  • Sattar Mohammadi Esfarjani
    Affiliation

    Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran, P. O. B. 8514143131

Abstract

In this study, a non-classical approach was developed to analyze nonlinear free and forced vibration of an Axially Functionally Graded (AFG) microbeam by means of modified couple stress theory. The beam is considered as Euler-Bernoulli type supported on a three-layered elastic foundation with Von-Karman geometric nonlinearity. Small size effects included in the analysis by considering the length scale parameter. It is assumed that the mass density and elasticity modulus varies continuously in the axial direction according to the power law form. Hamilton's principle was implemented to derive the nonlinear governing partial differential equation concerning associated boundary conditions. The nonlinear partial differential equation was reduced to some nonlinear ordinary differential equations via Galerkin's discretization technique. He's Variational iteration methods were implemented to obtain approximate analytical expressions for the frequency response as well as the forced vibration response of the microbeam with doubly-clamped end conditions. In this study, some factors influencing the forced vibration response were investigated. Specifically, the influence of the length scale parameter, the length of the microbeam, the power index, the Winkler parameter, the Pasternak parameter, and the nonlinear parameter on the nonlinear natural frequency as well as the amplitude of forced response have been investigated.

Keywords: nonlinear vibration, Functionally Graded Material (FGM), nonlinear elastic foundation, modified couple stress theory, He's variational method
Published online
2020-04-08
How to Cite
Alimoradzadeh, M., Salehi, M., Mohammadi Esfarjani, S. “Nonlinear Vibration Analysis of Axially Functionally Graded Microbeams Based on Nonlinear Elastic Foundation Using Modified Couple Stress Theory”, Periodica Polytechnica Mechanical Engineering, 64(2), pp. 97-108, 2020. https://doi.org/10.3311/PPme.11684
Section
Articles