Experimental Investigation of the Influence of Stacking Sequence and Delamination Size on the Natural Frequencies of Delaminated Composite Plate

The vibration properties of the composite structures is critical to the reliability and durability of the structures. Vibration becomes worst in case the delamination is present within laminates. In this research work, experimental, finite element and analytical techniques have been applied in order to analyze the influence of stacking sequence and delamination sizes on the natural frequencies of carbon fiber reinforced polymer composite (CFRP) plate with and without delamination. The boundary conditions in this research work was (SSSS) (all sides simply supported. Experiments were performed to study the vibration characteristics of (CFRP) delaminated composite plate. Software package ABQUS was used to model and analyze the vibration response of carbon fiber reinforced polymer composite plate for (SSSS) boundary condition and the effect of stacking sequence and delamination size was calculated. Rayleigh- Ritz Method was used to find the natural frequencies for different delamination sizes and stacking sequences. The results was concluded that natural frequencies were significantly affected by the delamination sizes and stacking sequences. Stacking sequence of (0/90/45/90) showed higher values of natural frequencies in lower mode subjected to all-sides simply supported boundary conditions. It was interesting to see that there were small differences in values of natural frequencies among the stacking sequences for lower modes but the difference gradually increased in case of higher modes.