modified Free Vibration Analysis of Composite Laminated Beams

(osama mohammed elmardi suleiman khayal) #1

This study addresses the problem of free vibration of laminated composite beams. Six end boundary conditions for
beams are considered: clamped-clamped; hinged-hinged; free-free; clamped-hinged; clamped-free; and hinged-free
beams. 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/epoxy
composites with those found in literature. The effects of the aspect ratio, fiber orientation, and the beam endmovements
on 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 shapes
of 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 natural
frequencies. The longitudinal modes of free vibration are sensitive to axial motion of the ends, whereas the transverse
modes depend solely on the condition of the lateral supports. It was also found that natural frequencies decrease as
the aspect ratio and/or the angle of orientation increase. The free-free and hinged-free beams are found to have the
highest frequencies of all beams although they look less constrained.
Keywords:Laminated beam, finite element, shears deformation, natural frequencies, and free vibration.3453_pdf.pdf (1.1% u)