In this study, the effects of both lamination

scheme and boundary conditions on the natural

frequencies of free vibration of laminated composite decks

beams were investigated. The problem is analyzed and

solved using the energy approach which is formulated by a

finite element model. Lamination schemes for symmetric

and non-symmetric laminated beams were studied. Six

boundary conditions are considered; clamped-free (CF),

hinged-hinged (HH), clamped-clamped (CC), hingedclamped

(HC), hinged-free (HF), free-free (FF). Each

beam has either movable ends or immovable ends. It is

found that both symmetrically and anti-symmetrically

laminated beams of similar size and end conditions have

equal natural frequencies which, generally, decrease as the

angle of orientation increases. Also, It is found that the

more constrained beams have the higher values of natural

frequencies of transverse vibration. However, the free-free

and hinged-free beams are found to have the highest

frequencies of transverse vibration amongst all beams

although they look less constrained. This behavior is due to

the fact that the first mode of the two beams is equal zero

(rigid body motion), and replaced by the second mode to

be the fundamental mode. The values of the natural

frequencies of longitudinal modes are found to be the same

for all beams with movable ends since they are generated

by longitudinal movements only. But for immovable ends,

the clamped-free and hinged-free beams have equal

frequencies in longitudinal vibration, and those of the

other beams are also the same.61-66,Tesma301,IJEAST.pdf (349.0% u)

# VIBRATION OF LAMINATED COMPOSITE DECKS BEAMS

**osama64**(osama mohammed elmardi suleiman khayal) #1