Abstract— Composite materials are widely used in aeronautical, marine and automotive industries, because of their excellent mechanical properties, low density and ease of manufacture. However, composite laminates are susceptible to delaminations, which may not be visible externally, but can substantially affect the performance of the structure. Vibration test, in particular delamination detection, in the composite structures is an active research area. D’Alembert principle is used to determine the theoretical natural frequency of laminated orthotropic composite plate. The present free vibration experimental study of simply supported square laminated plates is based on the comparison between natural frequencies of healthy and delaminated composite plates. The test square plates made of hand lay up 8 layers Eglass woven fibre and epoxy resin are used. The present paper discusses the observations made on the measured natural frequencies of vibration testing from both the healthy and the delaminated square simply supported plates. The possibility of the delamination detection by vibration test is also introduced. The effects of delamination area on the natural frequencies of the plate are presented. The delamination in composite laminates has considerable effect on the natural frequencies of the plate.

Index Terms— Laminated composite material, Free vibration, Delamination

Cite: R Sultan, S Guirguis M Younes, and E El-Soaly, " Delamination Detection of Composite Laminates Using Natural Frequency Vibration Method," International Journal of Mechanical Engineering and Robotics Research, Vol. 1, No. 2, pp. 286-296, July 2012.