Free Vibration Analysis Of Laminated Composite Beam With A Transverse Crack
In many structures like high speed machineries, aircrafts and light weight structures composite beams and beam
like structures are main constituent elements. Cracks induced in these structural elements cause serious failure and
monitoring of these cracks is essential. The presence of these cracks influences the dynamic characteristics of the structural
elements. The influence of cracks on dynamic characteristics like natural frequencies, modes of vibration of structures,
buckling loads has been the subject of many investigations. However studies related to behaviour of composite cracked
structures subject to in-plane loads are scarce in literature. Hence the changes in natural frequencies, mode shapes have been
the subject of interest of many investigations. Present work deals with the vibration analysis of a cantilever beam made from
graphite fiber reinforced polyimide with a transverse one-edge non-propagating open crack using ANSYS 14.5. The effects
of various parameters like crack location, crack depth, volume fraction of fibers and fibers orientations upon the changes of
the natural frequencies of the beam are studied. The results obtained are analyzed. It is found that, presence of crack in a
beam decreases the natural frequency which is more pronounced when the crack is near the fixed support and the crack
depth is more. The natural frequency of the cracked beam is found to be maximum at about nearly 1.0 volume fraction of
fibres and the frequency for any depth of crack increases with the increase of angle of fibres. At last frequencies of two
beams Graphite fiber reinforced polymide composite and E-Glass fiber polymer composite beams are compared.
Keywords: ANSYS, Crack, Fibre- Reinforced Composite beams, Modal Analysis, Natural frequency.