Investigating the effects of delamination location and size on the vibration behaviour of laminated composite beams

Composite structures are extensively used in various industries like aerospace, automotive and marine due to their excellent mechanical properties coupled with low density. However the composite structures are very sensitive to processing and working conditions. One of the most common defects that have driven attention of many researchers is the delamination. Present investigation is focussed on studying the effect of delamination location and estimating its effect on natural frequency of composite beams using commercial finite element software, ANSYS. Different ply lay ups are considered for study in both finite elements analysis and analytical formulations. The finite element results are compared with the analytical ones to validate the perfect beam design. The natural frequency is found to reduce with increase in delamination size for both cantilever and simply supported beam. Additionally, the natural frequency in simply supported composite beam is found to be higher than that in cantilever composite beam as expected due to the increased bending stiffness. Further, natural frequency of symmetric laminate is found to be higher than the cross ply laminate for both cantilever and simply supported composite beams.