Nonlinear Free Vibration Analysis of Functionally Graded Sandwich Beam with Magnetorheological Fluid Core Using Timoshenko Beam Theory

In this paper, the analysis of nonlinear free vibrations of beams made of functionally graded materials with magnetorheological fluid as core is investigated. It is assumed that the beam is made of three layers including constraining layer, magnetorheological fluid and base layer and is located on Simply-Simply, Clamped-Simply and Clamped–Clamped supports. The governing equations of the beam are derived using the Hamilton’s principle. To obtain the vibrational frequencies, the theory of Timoshenko beam is used by the Generalized Differential Quadrature method. The effects of magnetic field intensity, power law exponents, core thickness and constraining layer thickness and the length of the beam on natural frequency and modal loss factor related to different frequencies modes for the three boundary conditions have been investigated. The results show the effects of physical and geometrical parameters regarding the natural frequency and modal loss factor of the sandwich beam with different modes. Also, the frequency and loss factor values obtained from Generalized Differential Quadrature method are very close to the results obtained by the Finite Element method. This shows the accuracy and precision of this method.

کلیدواژه ها:

Nonlinear free vibration ، Functionally graded sandwich beam ، Magnetorheological fluid core ، Euler Bernoulli and Timoshenko beam theories