Keywords
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Functionally graded materials, graphene platelets, polymer nanocomposites, third-order shear deformation theory,
rotating pre-twisted laminated blades/beams, free vibration
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Abstract
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This work presents an investigation on the free vibration behavior of rotating pre-twisted functionally graded graphene
platelets reinforced composite (FG-GPLRC) laminated blades/beams with an attached point mass. The considered
beams are constituted of NL layers which are bonded perfectly and made of a mixture of isotropic polymer matrix
and graphene platelets (GPLs). The weight fraction of GPLs changes in a layer-wise manner. The effective material
properties of FG-GPLRC layers are computed by using the modified Halpin-Tsai model together with rule of mixture.
The free vibration eigenvalue equations are developed based on the Reddy’s third-order shear deformation theory
(TSDT) using the Chebyshev–Ritz method under different boundary conditions. After validating the approach, the
influences of the GPLs distribution pattern, GPLs weight fraction, angular velocity, the variation of the angle of twist
along the beam axis, the ratio of attached mass to the beam mass, boundary conditions, position of attached mass, and
geometry on the vibration behavior are investigated. The findings demonstrate that the natural frequencies of the
rotating pre-twisted FG-GPLRC laminated beams significantly increases by adding a very small amount of GPLs into
polymer matrix. It is shown that placing more GPLs near the top and bottom surfaces of the pre-twisted beam is an
effective way to strengthen the pre-twisted beam stiffness and increase the natural frequencies.
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