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 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 Vibration and stability characteristics of functionally graded sandwich plates with/without porosity subjected to localized edge loadings(Taylor and Francis Ltd., 2023) Swaminathan, K.; Hirannaiah, S.; Rajanna, T.This article investigates the influence of porosity and localized edge loads on the vibration and buckling characteristics of functionally graded material (FGM) plates using the finite element (FE) method. The analysis is carried out by choosing a single-layer FGM and two different types of FGM sandwich plates in such a way that there is no material discontinuity along the thickness direction. The porosity imperfections are accounted for in this study as criteria of stiffness reduction and are incorporated using modified power law distribution. The vibration and buckling responses are studied by considering four types of localized edge loads on plates with different porosity distributions. The application of different types of localized edge loads on the plate leads to the development of nonuniform in-plane stresses. Hence, they are computed first by using a dynamic approach before obtaining the buckling loads. The accuracy of the FE formulation is first validated for FGM plates by comparing the natural frequencies and the critical buckling loads obtained in the present investigation with the solutions already available in the literature. After validating the accuracy, detailed parametric studies have been performed on plates with varying volume fraction exponent, porosity distribution, porosity index, side-to-thickness ratio, load width ratio, aspect ratio, and support condition, and the results are presented with appropriate conclusions. A probabilistic sensitivity analysis is carried out to identify the significant parameter affecting the buckling load and natural frequency of porous FGM plates subjected to localized edge loads, which considerably aids in the design of the FGM plates. © 2022 Taylor & Francis Group, LLC.