An Experimental Investigation on Natural Frequencies of Delaminated Composite Beams

This paper deals with the effects of delamination size and its lengthwise location on the vibration characteristics of cross-ply laminated composite beams experimentally. The modal tests were carried out on the delaminated specimens. These experiments are focused on the effect of the axial location of delamination on the first three natural frequencies. Also, delamination size is relatively small (dimensionless length, alL is 0.20, 0.10 and 0.05) respect to the available experimental works in the literature. To verify the results, an analytical constrained mode models are introduced and compared for the first three modes. Experimental results for frequency reduction have good agreement with analytical ones in many cases. All results are considered under the both clamped-free and clamped-clamped boundary conditions.