Free Vibration Analysis of Composite Laminated Beams.pdf

This study addresses the problem of free vibration of laminated composite beams. Six end boundary conditions forbeams are considered: clamped-clamped; hinged-hinged; free-free; clamped-hinged; clamped-free; and hinged-freebeams. The problem is analyzed and solved using the energy approach which is formulated by a finite element model.This method of analysis is verified by comparing the numerical results obtained for AS/3501-6 graphite/epoxycomposites with those found in literature. The effects of the aspect ratio, fiber orientation, and the beam endmovementson the non-dimensional natural frequencies of beams were included.The results of the non- dimensional frequencies for some special cases of lamination were included. The mode shapesof free vibration for all boundary conditions were plotted. It was found that symmetrically  / / /  and antisymmetrically / / /  laminated beams of similar dimensions and end conditions have equal naturalfrequencies. The longitudinal modes of free vibration are sensitive to axial motion of the ends, whereas the transversemodes depend solely on the condition of the lateral supports. It was also found that natural frequencies decrease asthe aspect ratio and/or the angle of orientation increase. The free-free and hinged-free beams are found to have thehighest frequencies of all beams although they look less constrained.