Faculty Publications
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Item Effect of lamination schemes on natural frequency and modal damping of fiber reinforced laminated beam using Ritz method(EDP Sciences, 2021) Somi Naidu, S.N.; Jeyaraj, J.; Mailan Chinnapandi, L.B.; Reddi, C.V.S.N.The current study focussed on analysing natural frequency and damping of laminated composite beams (LCBs) by varying fiber angle, aspect ratio, material property and boundary conditions. Ritz method with displacement field based on the shear and normal deformable theory is used and the modal damping is calculated using modal strain energy method. Effects of symmetric angle-ply and cross-ply, anti symmetric cross-ply, balanced and quasi-isotropic lay up schemes on modal damping are presented for the first time. Results revealed that influence of lay-up scheme on natural frequencies is significant for the thin beams while the modal damping of the thin beams are not sensitive to lay-up scheme. However, the lay-up scheme influences the damping significantly for the thick beams. Similarly, high strength fiber reinforced LCBs have higher natural frequency while low strength fiber reinforced LCBs have higher damping due to the better fiber-matrix interaction. © S.N. Balireddy et al., Published by EDP Sciences, 2021.Item Vibration analysis of a tapered laminated thick composite plate with ply drop-offs(Springer Verlag service@springer.de, 2015) Edwin Sudhagar, P.; Arumugam, A.; Vasudevan, R.; Jeyaraj, J.In this study, vibration characteristics of a tapered laminated thick composite plate have been investigated using finite element method by including the shear deformation and rotary inertia effects. The governing differential equations of motion of a tapered laminated thick composite plate are presented in the finite element formulation based on first-order shear deformation theory for three types of taper configurations. The effectiveness of the developed finite element formulation in identifying the various dynamic properties of a tapered laminated thick composite plate is demonstrated by comparing natural frequencies evaluated using the present FEM with those obtained from the experimental measurements and presented in the available literature. Various parametric studies are also performed to investigate the effect of taper configurations, aspect ratio, taper angle, angle ply orientation and boundary conditions on free and forced vibration responses of the structures. The comparison of the transverse free vibration mode shapes of the uniform and tapered composite plates under various boundary conditions is also presented. The forced vibration response of a composite plate is investigated to study the dynamic response of tapered composite plate under the harmonic force excitation in various tapered configurations. It is concluded that the dynamic properties of laminated thick composite plates could be tailored by dropping off the plies to yield various tapered composite plate. © 2015, Springer-Verlag Berlin Heidelberg.Item Free vibration and inherent material damping characteristics of boron-FRP plate: Influence of non-uniform uniaxial edge loads(EDP Sciences, 2021) Gunasekaran, V.; Jeyaraj, J.; Mailan Chinnapandi, L.B.The current investigation presents the analytical investigation on free vibration and inherent material damping of boron-FRP plate, subjected to non-uniform uniaxial edge loads. Initially critical buckling load (Pcr) is obtained, then followed by free vibration response and inherent material damping values for corresponding modal indices of the FRP plate is calculated for different load fraction of non-uniform uniaxial edge loads. The buckling load and free vibration response are obtained by using strain energy method and Reddy's TSDT respectively. It is observed that the nature of load and aspect ratio influence the bucking, free vibration and inherent material damping behaviour of the fibre reinforced polymer plate significantly. © V. Gunasekaran et al., Published by EDP Sciences, 2021.Item Acoustic radiation and transmission loss of FG-Graphene composite plate under nonuniform edge loading(Elsevier Ltd, 2021) Gunasekaran, V.; Jeyaraj, J.; Mailan Chinnapandi, L.B.The influence of nonuniform edge loads on the acoustic response of a functionally graded graphene reinforced composite plate is investigated analytically. The energy method is implemented to calculate the buckling load (Pcr). An analytical method based on Reddy's third-order shear deformation theorem is used to obtain the vibration response, and acoustic response is obtained using Rayleigh Integral. The nature of edge load variation on buckling and vibro-acoustic response is significant. Free vibration mode shape changes with an increase in edge load and consequently affects the resonant amplitude of responses also especially for the plates with a higher aspect ratio. Volume fraction and dispersion pattern of graphene nano-platelets also influences the resonance amplitudes. Plate with FG?GRCC dispersion pattern has improved buckling and vibro-acoustic response behavior. Similarly, change in sound transmission loss level is significant in the stiffness region compared to the damping and mass dominated region. © 2021 Elsevier Masson SASItem Static stability and vibration behavior of graphene platelets reinforced porous sandwich cylindrical panel under non-uniform edge loads using semi-analytical approach(Elsevier Ltd, 2022) Twinkle, C.M.; Jeyaraj, J.Buckling and free vibration characteristics of sandwich cylindrical panel with porous functionally graded graphene platelets (FG-GPL) core are investigated using semi-analytical approach. The effective mechanical properties are obtained by using properties of open cell foams and Halpin–Tsai micro mechanical model. The governing equations are obtained using Hamilton's principle, considering a higher order theory to account the transverse shear and solved by Galerkin's method. Effects of nature of in-plane edge load, distribution of porosity and GPL, porosity coefficient, GPL loading, core to total thickness ratio are analyzed in detail. It is shown that for a FG-GPL core sandwich cylindrical panel with high core thickness, even at higher amount of porosity the buckling resistance and free vibration frequency can be improved by properly tailoring both the GPL and porosity distribution. Moreover, a much variation in buckling and free vibration response with the type of in plane loading is observed and evident mode shape changes are observed with increase in aspect ratio. The cylindrical sandwich panel having a core with D-PD porosity variation and I-GPL-P pattern of GPL distribution has the maximum buckling resistance and free vibration frequency value. © 2021 Elsevier LtdItem Stability and dynamic behaviour of bi-directional functionally graded beam subjected to variable axial load(Elsevier Ltd, 2022) Somi Naidu, S.N.; Jeyaraj, J.The current study emphasizes static stability and dynamic characteristics of bi-directional functionally graded beams subjected to variable axial loads using the Ritz method and Reddy's beam theory. The material property is varied as a function of the gradation pattern along with the length and thickness directions. The solutions procedures are tested against the results in the literature to show the accuracy of the present method. The influence of uniform, linear, and parabolic axial loads along the length of the beam on buckling and vibration responses are investigated. There is a remarkable variation observed in both the responses, by changing the material properties from isotropic to bi-direction functionally graded. Furthermore, the study reveals that higher stiffness is achieved by the material gradation index increment along the thickness direction compared to the lengthwise gradation index increment. Even the variations in the aspect ratios and end conditions are depicting significant variations in the buckling and vibration responses. Buckling and free vibration modes are also highly sensitive to the nature of variable axial loads and gradation index. © 2022 Elsevier Ltd