Faculty Publications
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Item Analytical investigation on free vibration frequencies of polymer nano composite plate: Effect of graphene grading and non-uniform edge loading(Elsevier Ltd, 2020) Gunasekaran, V.; Jeyaraj, J.; Mailan Chinnapandi, L.B.M.An analytical investigation carried out on free vibration characteristics of functionally graded graphene reinforced nanocomposite (FG-GRC) plate under different non-uniform edge loads is presented. Graphene nano-platelets (GPLs) are homogeneously dispersed and graded by varying weight fraction through the thickness. An analytical method based on strain energy approach is adopted to estimate the buckling load. Natural frequencies of the FG-GRC plate are attained using analytical solutions derived based on Reddy's third-order shear deformation theorem (TDST). Results revealed that buckling and free vibration behavior of the plate is influenced by the GPLs dispersion pattern and weight fraction under non-uniform edge loads. It is also observed that buckling mode and the fundamental vibration mode of the plate under combined tensile-compression load is entirely different from the other non-uniform edge load cases. © 2020 Elsevier LtdItem Acoustic response behavior of porous 3D graphene foam plate(Elsevier Ltd, 2020) Kumar, A.; Gunasekaran, V.; Mailan Chinnapandi, L.B.M.; Jeyaraj, J.Sound radiation and sound transmission loss (STL) behavior of porous 3D graphene (3D-GrF) foam plate are presented. Two variable refined plate theory which includes both transverse bending and shear stresses is used to model the plate and Navier's solution is used to calculate the vibration responses while Rayleigh integral is used to analyze the acoustic response. Variation in free vibration frequencies with the nature of porosity distribution is significant for the 3D-GrF plates having higher porosity co-efficient. The natural frequency of the 3D-GrF plate with more porosity around the center and less porosity at the outer surfaces is high. However, resonant amplitudes of the responses and STL of the plates are controlled by both the nature of the porosity distribution pattern and porosity co-efficient. In general, STL of the plate with less porosity around the center and high porosity at the extreme surfaces is high compared to the other cases. © 2020 Elsevier LtdItem Free vibration and stability of graphene platelet reinforced porous nano-composite cylindrical panel: Influence of grading, porosity and non-uniform edge loads(Elsevier Ltd, 2021) Twinkle, T.; Jeyaraj, J.Buckling and vibration characteristics of functionally graded(FG) porous(P), graphene platelet (GPL) reinforced cylindrical panel are presented. A multilayer model is considered for analysis with graphene and internal pores distribution varying in an uniformly or two different non-uniformly manner along the thickness. To evaluate the effective mechanical properties, extended rule of mixture together with modified Halpin-Tsai micromechanics model and mechanical properties of open-cell metal foams is used. Considering a higher order shear deformation theory, characteristics of the FG-P-GPL reinforced cylindrical panel under different edge loads such as uniform, triangular, trapezoidal and parabolic are investigated. The Hamilton's principle is used to formulate the governing partial differential equations and buckling and free vibration solutions are obtained by employing the Galerkins method. The influences of grading of GPL and internal pores, porosity coefficient on buckling and dynamic characteristics of functionally graded GPL reinforced porous cylindrical panel under uniform and non-uniform in-plane loads are presented. © 2020 Elsevier LtdItem Analytical Solution for Sound Radiation Characteristics of Graphene Nanocomposites Plate: Effect of Porosity and Variable Edge Load(World Scientific, 2021) Gunasekaran, V.; Jeyaraj, J.; Mailan Chinnapandi, L.B.; Kumar, A.The effects of graded dispersion of graphene platelets and porosity on vibro-acoustics of nanocomposite plate exposed to variable edge loads are analytically investigated. Voigt and Halpin-Tsai micromechanics model is used to obtain effective properties of the porous graphene nanocomposites. The strain energy technique is implemented to estimate the buckling load (Pcr). By means of Reddy's third-order shear deformation theorem and Rayleigh Integral, vibration and acoustic responses are obtained. After validating the present analysis with the published results, the nature of edge loads on buckling and vibro-acoustic response is significant. It is noted that an increase in the intensity of non-uniform in-plane loads leads to changes in free vibration modes and resonant amplitude of response. The weight percentage and grading pattern of graphene reinforcement cause the stiffness hardening effect, whereas porosity distribution and coefficients cause the stiffness softening effect on the nanocomposite plate. It is found that the plate with symmetric distribution of graphene platelets with more concentration at the surface and symmetric porosity variation with more porosity at the center radiates less sound power. © 2021 World Scientific Publishing Company.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 Acoustic fluid–structure study of 2D cavity with composite curved flexible walls using graphene platelets reinforcement by higher-order finite element approach(Elsevier Ltd, 2021) Jeyaraj, J.; Gupta, P.; Vasudevan, V.; Polit, O.; Manickam, G.In the present study, acousto-vibration analysis of 2D fluid-filled cavities/tanks having flat and curved flexible walls is made using a trigonometric function based shear deformable theory and the Helmholtz wave model for fluid domain. The governing equation formed here is solved through higher-order finite element approach. The walls are modeled by C1 continuous 3-noded beam element and the fluid is idealized using an eight-noded quadrilateral element. Structural and coupled frequencies are evaluated for fluid-filled cavities with rigid/flexible vertical walls along with flat/curved beam on top. The sound pressure level is also predicted in the fluid domain due to a steady-state mechanical harmonic load on the top of the cavity. This investigation is conducted for metallic cavities and then extended to graphene platelets reinforced cavity. The effect of degree of fluid–structure coupling is examined assuming different fluid domains. Considering a wide range of cavity geometry and material parameters such as thickness ratio, curved beam angle, graded porosity and graphene platelets, porosity coefficient, loading of GPL, fluid medium, a comprehensive investigation is depicted to highlight their impacts on vibro-acoustic nature of fluid-filled cavities. It is observed that the dynamic characteristics of rigid and flexible wall cavities are significantly different from each other. © 2021 Elsevier LtdItem 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 Thermal buckling and vibro-acoustic behaviour of functionally graded graphene polymer layered composites subjected to in-plane temperature variance(SAGE Publications Ltd, 2022) John, B.O.; Hassan, F.U.; George, N.; Chacko, T.; Bhagat, V.S.; Jeyaraj, J.; Kiran Kumar Reddy, R.The current study reports the thermal buckling, vibration and acoustic characteristics of functionally graded graphene polymer layer composite plates subjected to the in-plane temperature variance. The macroscopic properties of the composites are evaluated using the modified rule of mixtures to compute the layer-wise properties of an functionally graded graphene polymer layer composite plate. The critical buckling temperature is computed and compared for various functional gradings, boundary conditions and in-plane temperature variances. The in-plane temperature variance showed a major impact on the critical thermal buckling temperature and respective mode shapes. The vibro-acoustic behaviour of the functionally graded graphene polymer layer composite plate is investigated and documented keeping critical buckling temperature as a function. With an increase in thermal load and the nature of in-plane temperature variance, the vibro-acoustic results showed significant difference in velocity and acoustic response. For functionally graded graphene polymer layer composite plate with one free edge, the difference was statistically significant as indicated by an octave band plot. We conclude that the portion of the functionally graded graphene polymer layer composite plate that is subjected to the higher temperature in an in-plane temperature variance, as well as the nature of the boundary conditions may exacerbate the effect of in-plane temperature variance and are crucial in predicting vibro-acoustic characteristics. © IMechE 2022.Item Stability and dynamic behavior of porous FGM beam: influence of graded porosity, graphene platelets, and axially varying loads(Springer Science and Business Media Deutschland GmbH, 2022) Priyanka, R.; Twinkle, C.M.; Jeyaraj, J.This paper investigates the free vibration and buckling behaviors of functionally graded graphene platelets (FG-GPLs) reinforced porous beam under axially variable loads. The internal pores and GPLs are either uniformly or non-uniformly distributed along the thickness direction. Halpin–Tsai micromechanics model is used to calculate the effective elastic modulus. The variation of Poisson’s ratio along the thickness and the relation between mass density and porosity coefficients are determined using mechanical properties of closed-cell solid under the Gaussian random scheme. The equilibrium equations are derived by Hamilton’s principles, and critical buckling load and dimensionless natural frequency are determined by Ritz formulation. Results revealed that buckling and free vibration behavior of the porous FG-GPL beam are influenced by the GPLs grading pattern and the type of axially varying load. Furthermore, the grading pattern of porosity has more influence on the buckling behavior compared to the free vibration behavior. It is also observed that buckling mode and the fundamental vibration mode of the porous FG-GPL are influenced by the loading conditions and remain unaffected by the grading pattern of porosities and GPLs. © 2021, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.Item Buckling and vibration of beams using Ritz method: Effects of axial grading of GPL and axially varying load(Taylor and Francis Ltd., 2024) Patil, H.H.; Jeyaraj, J.; Eltaher, M.A.The present work discusses buckling and vibration characteristics of axially functionally graded (AFG) graphene platelet (GPL) composite beams exposed to axially varying loads (AVLs). Timoshenko beam composition with five different types of axial grading GPLs subjected to six different types of AVLs are studied. The effective elastic properties are obtained using Halpin-Tsai model and the equations of motion are obtained following the Hamilton’s principle. Then the equations are solved for buckling and vibration analysis using the Ritz method. Influences of nature of axial grading of GPLs and load, content of GPL, and structural boundary conditions are investigated through detailed parametric studies. It is found that the grading pattern of GPLs not only influences the buckling load, but also changes buckling mode shapes of the beam at specific type of AVL. Furthermore, results reveal that buckling and vibration characteristics of beam enhanced in case of AFGM-A type for most of the load cases studied. The proposed study will be helpful for the structural engineers to select the nature of graded distribution of GPLs for the given type of AVL and design the structural member. © 2023 Taylor & Francis Group, LLC.