Free Vibration Analysis of Composite Beam Consisting Fibers with Variable Volume Fraction

In this paper, free vibration of fiber-reinforced composite beam in which volume fraction of its fibers varies longitudinally according to power law model is analyzed by using finite elementmethod. Advanced micromechanical model is employed to represent its mechanical properties including elastic and physical properties of this beam. Governing equations of motionderived based on Timoshenko beam theory are descritized by utilizing weak form formulationand spatial approximation of displacement variables into mass and stiffness matrices. Each array of matrices obtained in form of integral is computed numerically by Gauss-Legendre method and finite element codes according to stated method are written in MATLAB software. Under various boundary conditions, computed natural frequencies ofthis composite beam with variable volume fraction of fibers are compared with traditional composite ones in which volume fraction of fiber is constant. Numerical results show that depending on boundary conditions, using fibers with variable volume fraction in composite beam will result in increase of fundamental frequencies, albeit average volume fraction and fiber orientations are the same

کلیدواژه ها:

Free vibration ، Timoshenko beam ، Fiber reinforced composite ، Finite element