Influence of envelope and core angles on natural frequency of a cantilever beam – A finite element approach

Abstract In the present work formulation of the stiffness matrix is carried out for laminated composites Envelope and core angles are taken with three plies with core thickness and envelope thickness varied for cantilever beam widely used in Aircraft structures. The natural frequency of the structure was found using the stiffness formulated for different orientations of core and envelope angles and its effect is investigated for glass epoxy and graphite-epoxy laminated composite beams keeping the density constant. Natural frequencies decrease when the orientation of laminae (either core or envelope) is increased from 00 to 900. But increasing the orientation of the envelope has a significant effect on natural frequencies when compared to that of the core angle.