Faculty Publications
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Item Effect of Porosity Distribution on Vibration and Stability Characteristics of FGM Plates Subjected to Nonlinearly Varying Edge Loads(Springer Science and Business Media Deutschland GmbH, 2023) Swaminathan, K.; Hirannaiah, S.; Rajanna, T.In this article, the consequences of porosity type of imperfection on vibration and stability characteristics of Functionally Graded Material (FGM) plate members are examined. Since it is challenging to predict the type of porosity distribution in the plate, four diverse varieties of porosity distributions varying through the thickness are considered during the modelling of FGM plates. The porosity effect is included in material modelling by means of modified rule of mixture. The in-plane edge loads acting on plates are seldom uniform in nature during the operational condition. And hence, vibration and stability characteristics of the FGM plates comprising porosity is analyzed considering nonlinearly varying in-plane edge load incorporating Finite element (FE) method. The numerical outcomes obtained are compared to those reported in the literature to help decide the formulation's correctness. The effect of geometric configuration, volume fraction exponent, porosity and loading on vibration and stability characteristics of FGM plate member with porosity is investigated. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Item Influence of Porosity and Temperature Load on Buckling Characteristics of Functionally Graded Material Plates(Springer, 2024) Swaminathan, K.; Hirannaiah, H.; Rajanna, T.Functionally graded material (FGM) plate is usually exposed to a thermal environment, and their mechanical behaviour under temperature loads is of great importance to the research community. Therefore, the objective of the current investigation is to study the impact of porosity and temperature loads on the buckling characteristics of FGM plates. The effective material properties of porous FGM plates are found using modified power law distributions, and the porosity defects are accounted for in this study as criteria of stiffness reduction. The buckling responses of porous FGM plates are investigated by incorporating four types of different porosity distributions. The analysis is carried out using the Finite Element (FE) technique. The accuracy of the current formulation is authenticated by comparing the present results obtained with analytical results existing in the literature. After the validation, the influence of several significant parameters such as the porosity, the volume fraction exponent, side-thickness ratio, support conditions and aspect ratio on buckling responses of the porous FGM plate under temperature loads is evaluated. Results showed that the buckling response of the FGM plate is substantially affected by porosity and temperature loads. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Transverse stresses in antisymmetric angle ply sandwich plates - Analytical evaluation of refined higher order shear deformation theories(2010) Swaminathan, K.; Sangwai, G.R.In the present work two higher order computational models with 9 and 12 DOF already available in the literature for which analytical formulations and solutions for the stress analysis not yet reported are considered. In addition to these models, few higher order models and the first order model developed by other investigators are also considered for the evaluation. A simply supported plate subjected to sinusoidal transverse load with SS-2 boundary conditions is considered for the analysis. Solutions are obtained using Navier's technique. Transverse stresses are computed by post processing technique and the accuracy of models in predicting the stresses is evaluated. © (2010) Trans Tech Publications.Item Experimental study on shear strengthening of RC beams using externally bonded carbon fiber reinforced polymer sheets(2011) Swaminathan, K.; Chethana, H.A.; Biradar, G.This paper presents the experimental results of the Reinforced Concrete (RC) beams strengthened in shear with externally bonded Carbon Fiber Reinforced Polymer (CFRP) strips. The investigation mainly focus on the shear strengthening effect of bonded CFRP strips on the ultimate shear strength and deformation behaviour of RC beams. In total eight beams were cast, seven without any internal shear reinforcement and the eighth with internal stirrups. Out of the seven beams without any shear reinforcement, one was used as control beam and the remaining beams were strengthened with CFRP strips with different wrapping schemes. All the beams were tested under simply supported condition with four point bending. The failure process of all the beams was carefully monitored and the results with regard to strain, deflection, first crack appearance, crack propagation and the shear carrying capacity are discussed. Results showed that the crack propagation can be better arrested in beams strengthened with CFRP strips. The shear enhancement of CFRP strengthened beams were in the range of 26 to 34 percent as compared to control beam. This study shows that the use of CFRP strips significantly increases the shear capacity of RC beams. © 2011, Advanced Engineering Solutions.Item Analytical solutions using a higher-order refined theory for the static analysis of functionally graded material plates(2013) Swaminathan, K.; Naveenkumar, D.T.Analytical formulations and solutions to the static analysis of simply supported Functionally Graded Material (FGM) plates hitherto not reported in the literature based on a higherorder refined shear deformation theory with nine degrees-of-freedom already reported in the literature are presented. This computational model incorporates the plate deformations which account for the effect of transverse shear deformation. The transverse displacement is assumed to be constant throughout the thickness. In addition, another higher order theory with five degrees-offreedom and the first order theory already reported in the literature are also considered for comparison. The governing equations of equilibrium using all the computational models are derived using the Principle of Minimum Potential Energy (PMPE) and the analytical solutions are obtained in closed-form using Navier's solution technique. A simply supported plate with SS-1 boundary conditions subjected to transverse loading is considered for all the problems under investigation. The varying parameters considered are the side-to-thickness ratio, power law function, edge ratio and the degree of anisotropy. Correctness of the formulation and the solution method is first established and then extensive numerical results using all the models are presented which will serve as a bench mark for future investigations. © (2013) Trans Tech Publications, Switzerland.Item Free vibration analysis of single and multilayered sandwich FGM plates-assessment of higher order refined theories(2014) Swaminathan, K.; Naveenkumar, D.T.Analytical formulations and solutions for natural frequency analysis of functionally graded material (FGM) plates based on two higher-order refined shear deformation theories with 9 and 12 degrees-of-freedom are presented. The displacement model with 12 degrees-of-freedom considers the effect of both transverse shear and normal strain/stress while the other considers only the effect of transverse shear deformation. In addition another higher-order model and the firstorder model developed by other investigators and available in the literature are also presented for the evaluation purpose. For mathematical modeling purposes, the Poisson's ratio of the material is considered as constant whereas Young's modulus is assumed to vary through the thickness according to the power law function. The equations of motion are derived using Hamilton's principle. Solutions are obtained in closed-form using Navier's technique and solving the eigenvalue equation. The accuracy of the theoretical formulations and the solution method using the present two higher-order refined models is first established by comparing the results generated in the present investigation with the 3D elasticity solutions already reported in the literature. After establishing the accuracy of predictions, benchmark results for the natural frequencies using all the four models are presented for single layer FGM plate and multi layered FGM sandwich plate with varying edge ratios and side-to-thickness ratios. © (2014) Trans Tech Publications, Switzerland.Item Higher order refined computational models for the thermo-elastic analysis of FGM plates(CRC Press/Balkema http://Pub.NL@taylorandfrancis.com, 2016) Swaminathan, K.; Sangeetha, D.M.Analytical formulations and solutions to the thermo-elastic analysis of Functionally Graded Material (FGM) plates hitherto not reported in the literature based on two higher-order refined computational models with 9 and 12 degrees-of-freedom already available in the literature are presented. The in-plane and the through the thickness variation of temperature is assumed to be sinusoidal and nonlinear respectively and is solved using one-dimensional steady state heat conduction equation. The accuracy of predictions of these two models is first established by comparing the results with the exact 3-D elasticity solutions already reported in the literature. Upon establishing the accuracy, numerical results are obtained for the simply supported FGM plates subjected to thermal loads with varying material and plate parameters. Studies are performed by varying the length to breadth ratio, side-to-thickness ratio and power law parameter. Bench mark results using the two models are presented for the displacements, in-plane and transverse stresses. © 2016 Taylor & Francis Group, London.Item Buckling analysis of functionally graded materials by dynamic approach(Elsevier Ltd, 2020) Swaminathan, K.; Hirannaiah, H.; Rajanna, T.Laminated composites exhibit difference in the mechanical properties at the interface between two materials resulting in stress concentration. This may lead to damages in the form of delamination, matrix cracking and adhesive bond separation. Functionally Graded Materials (FGM) are formed by gradual variation of two or more material over a particular volume, thereby overcomes these issues. Buckling problems of FGM plates are usually solved by static approach. In some cases, particularly non-uniform loading and geometric discontinuity, the stress concentration usually occurs. In such cases, the solution to the buckling problem by dynamic approach is most suitable. In the dynamic approach, the natural frequencies are calculated by applying in-plane loads. As the intensity of the in-plane load increases, the frequency of the material decreases and finally becomes zero at the onset of buckling. The load at which the natural frequency becomes zero that load is called a buckling load. In this investigation, the vibration and buckling characteristics of FGM panels subjected to uniaxial and biaxial loading conditions have been studied by using the finite element method (F.E.M). In the Finite element (FE) formulation, the effective material properties of FGM plates are assumed to vary in the thickness direction according to the power-law distribution of volume fraction of the constituents. The plate is modelled by using 8-noded serendipity element by incorporating the effect of transverse shear deformation and rotary inertia. The effect of different parameters such as volume fraction index (n), the thickness of the panel (h) and boundary condition of the plate are considered to study the buckling behaviour of the FGM plate under uniaxial loading conditions. © 2020 Elsevier Ltd. All rights reserved.Item Effect of initial stresses on vibration behavior of functionally graded materials(Elsevier Ltd, 2020) Swaminathan, K.; Hirannaiah, H.; Rajanna, T.Functionally Graded Materials (FGM) is the result of continuous gradation of two or more constituent materials over a certain volume. This type of material overcomes many problems, particularly delamination, cracking and damages which are very frequently found in laminated composite materials. The FGMs are commonly found in space structures, and these structural elements are subjected to various kinds of loadings during its service period, in which in-plane loading is the one which significantly affects the vibration characteristics of the structural elements. In this investigation, the effect of tensile and compressive stresses on vibration characteristics of FG panels has been studied by using finite element technique (FE). For mathematical modelling Poisson's ratio is assumed constant and Young's modulus of elasticity is assumed to vary according to the power-law distribution of volume fraction of the constituents. The plate is modelled by using 8-noded isoparametric element by considering the effect of transverse shear deformation and rotary inertia. The effect of different factors such as volume fraction index, the thickness of the panel, boundary condition and tensile as well as compressive edge loads are considered to study the vibration behaviour of the FGM plate under tensile and compressive uniaxial edge loads. © 2020 Elsevier Ltd. All rights reserved.Item Buckling Response of Functionally Graded Material Plates with Cutouts Subjected to Linearly Varying Loads(Springer Science and Business Media Deutschland GmbH, 2022) Swaminathan, K.; Hirannaiah, H.; Rajanna, T.In most of the studies, the buckling problems are solved analytically based on the assumption that the plates are subjected to only uniform in-plane edge loads without any damages, in spite of the fact that, the real structural components are subjected to various kinds of non-uniform edge loads along with geometrical discontinuous. The current study provides numerical solutions for buckling problems of functionally graded material plates with and without circular cutouts subjected to linearly varying edge loads by using the finite element package (ABAQUS). The effective material properties are found along the thickness using the homogenization technique involving power law function. In the FE modelling, the plate is modelled by using eight noded elements (S8R5) with five degrees of freedom at each node. The influence of various parameters such as size of the cutout and its position, volume fraction index and type of loads are considered to investigate the effect of each parameter on the buckling phenomenon. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.