Free Vibration of Laminated Composite Plates with Cut-Out

Abstract

The laminated composite plate are basics components of structure used in various field of engineering such as turbine blades, airplane wing and helicopter blades as well as many others in civil, automotive and ship industries etc. due to their excellent high stiffness to weight ratio and strength to weight ratio. Cut-outs are provided in structure for venting, reducing weight and passage of electrical wires. Most of the structures are subjected to severe dynamic loading during their service life. This may lead to change the dynamics response of the structure. The presences of cut-outs not only reduce the strength of composite plate but also alter the dynamics characteristics of composite plate. Therefore, it necessitates predicting the dynamics responses of laminated composite plates with cut-outs with cost effective and good accuracy of these complex structures. This present paper deals with combined numerical and experimental approach on dynamics characteristics of laminated composite plate with square cut-outs. The laminated composite plates are made by using hand lay-up method. Bidirectional glass fibres are used as reinforcement and polyester resin as matrix for composite plate. The experimental dynamics test has been carried out by using different dimensions of plate with various design parameters such as cut out ratio (D/d ratio), position of cut out, aspect ratio (a/b ratio), no of layers, ply orientations under different boundary conditions. The natural frequencies of composite plate with cut-outs are determined numerically using ANSYS 14.5 software. The convergence study is done for numerically obtained results and compare with other existing literature. The experimental values are also compared with the result obtained from ANSYS 14.5 software. It was seen that the fundamental frequency decreases with increase the cut-out ratio (d/D ratio) under CFFF and SFSF boundary conditions. But fundamental frequency decreases with increase the cut-out ratio (d/D ratio) up to 0.2 under CFCF boundary condition. Further fundamental frequency increases on increase of cut-out ratio (d/D ratio).