Browsing by Author "Hirannaiah, H."

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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. Â© 2020 Elsevier Ltd. All rights reserved.
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. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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. Â© 2020 Elsevier Ltd. All rights reserved.
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.
Thermo-mechanical vibration and buckling analysis of porous FG sandwich plates with geometric discontinuity based on physical neutral surface
(Taylor and Francis Ltd., 2024) Hirannaiah, H.; Swaminathan, K.; Rajanna, T.
The effect of thermo-mechanical load coupling and porosity distributions on vibration and buckling characteristics of Functionally Graded Sandwich Plates (FGSPs) with cutouts is investigated by Finite Element (FE) formulation. Two sandwich configurations are considered and physical neutral surface is incorporated due to material asymmetry. Novel dynamic approach is proposed to evaluate buckling loads. Results obtained are compared with experimental, numerical solutions in literature and revealed that the FGSP buckling capacity under thermomechanical loads improves on using ceramic with lower thermal expansion coefficient. Also, at higher temperature rises, buckling capacity increases due to increasing porosity content, whereas capacity reduces at lower temperature rises. © 2023 Taylor & Francis Group, LLC.