Experimental and numerical study on vibration and buckling characteristics of laminated composite plates

Abstract

Composite materials are being increasingly used in automotive, civil, marine, and especially weight sensitive aerospace application, primarily because of its specific strength and stiffness. The present research is mostly experimental study based on vibration measurement and buckling behavior of industry driven woven fiber composite panels. The effects of different geometry, boundary conditions, aspect ratio and type of fiber and hygrothermal conditions on the natural frequencies of vibration and buckling of woven fiber composite panels are studied in this investigation. Experiments have also been conducted to study the vibration and buckling characteristics of carbon/glass hybrid plates for different lamination sequence and percentage of carbon and glass fiber. The finite element package, ANSYS 13.0 was used to obtain numerical results and validate the experimental results obtained. The free vibration characteristics are studied with FFT analyzer. The critical buckling load is determined using INSTRON 1195. From the results obtained it was observed that, the frequencies of vibration as well as critical buckling load increased with increase in thickness. As the conditioning temperature deviates from the manufacturing temperature, the natural frequencies decrease gradually. The increase in moisture concentration of the laminate results in decrease in the modal frequencies. The studies on hybrid plates show that they possess the advantages of both their constituent fibres and have properties intermediate to the properties of individual fibres. The effect of percentage composition and sequence of lamination of the fibres on vibrational and buckling characteristics of the composite plates were observed. It was observed that the failure due to tensile load in hybrids is governed by delamination between layers. The buckling results show that stiffer materials on outermost layer give maximum buckling strength compared to those with carbon fibres in inner layers.