Faculty Publications

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    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.
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    Buckling and Free Vibration Behavior of a Temperature Dependent FG-CNTRC Cylindrical Panel under Thermal Load
    (Elsevier Ltd, 2018) Bhagat, V.; Jeyaraj, P.; Murigendrappa, S.M.
    Present study deals with the buckling and free vibration behavior of functionally graded carbon-nanotubes reinforced composite (FG-CNTRC) cylindrical panel exposed to uniform thermal load. Stresses setup due to thermal load and temperature dependent properties influences the buckling and free vibration behavior of the heated structures. Approach employed in the present study consists of static analysis to compute thermal stresses, eigen-value buckling analysis to compute critical buckling temperature and finally modal analysis, taking thermal stresses into account. Influence of different CNTs grading pattern, CNTs volume fraction, geometric parameters, boundary constraints and temperature dependent properties on the buckling strength are investigated. It is observed that hybrid CNTs distribution pattern gives comparatively higher buckling strength and free vibration frequencies. Investigation on free vibration characteristics of the FG-CNTRC panel at elevated temperature signifies that the decline in free vibration frequencies is very drastic at a temperature close to buckling temperature along with temperature dependent properties. c 2017 Elsevier Ltd. All rights reserved. © 2018 Elsevier Ltd.
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    The Sector Finite Element for Thermal Buckling Analysis of Isotropic Annular Disc
    (Springer Science and Business Media Deutschland GmbH, 2024) Kumar, A.; Kadoli, R.; Joladarashi, S.
    Annular disc-type structural elements may be subjected to thermal loads other than mechanical loads. Buckling of annular disc due to thermal load could lead to non-operationality of the machineries. The present study illustrates a step-by-step procedure for setting up the finite element equations for solving the thermal buckling problem of the annular disc. Sector finite elements with four nodes and five degrees of freedom at each node are used to discretize the computational domain of an annular disc. Using the nodal coordinates, the nodal degree of freedom based on the thin plate theory of elasticity is assessed at each node of the sector finite element. The two-dimensional plane stress–strain relationship is invoked, as well as temperature effects. The work done by the external load owing to temperature effects is expressed using nonlinear strains. The first potential energy minimization produces the equation for pre-buckling analysis, whereas the second time minimization yields the eigenvalue problem for obtaining post-buckling findings. To solve for buckling factors, a FORTRAN code is constructed, and the results for an isotropic circular thin plate with varying isothermal conditions are compared to an analytical solution published in the literature. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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    Linear thermal buckling and free vibration analysis are presented for functionally graded cylindrical shells with clamped-clamped boundary condition based on temperature-dependent material properties. The material properties of functionally graded materials (FGM) shell are assumed to vary smoothly and continuously across the thickness. With high-temperature specified on the inner surface of the FGM shell and outer surface at ambient temperature, 1D heat conduction equation along the thickness of the shell is applied to determine the temperature distribution; thereby, the material properties based on temperature distribution are made available for thermal buckling and free vibration analysis. First-order shear deformation theory along with Fourier series expansion of the displacement variables in the circumferential direction are used to model the FGM shell. Numerical studies involved the understanding of the influence of the power-law index, r/h and l/r ratios on the critical buckling temperature. Free vibration studies of FGM shells under elevated temperature show that the fall in natural frequency is very drastic for the mode corresponding to the lowest natural frequency when compared to the lowest buckling temperature mode. © 2005 Elsevier Ltd. All rights reserved.
    (Academic Press, Buckling and free vibration analysis of functionally graded cylindrical shells subjected to a temperature-specified boundary condition) Kadoli, R.; Ganesan, N.
    2006
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    Buckling of non-uniformly heated isotropic beam: Experimental and theoretical investigations
    (Elsevier Ltd, 2016) George, N.; Jeyaraj, P.; Murigendrappa, S.M.
    Influence of non-uniform heating on critical buckling temperature of an aluminium beam has been investigated experimentally with the help of a novel experimental set-up developed in-house. Non-linear finite element analysis, considering the initial geometric imperfection, has been carried out to compare the experimentally obtained typical load-deflection curve. The linear critical buckling temperature predicted numerically are validated with analytical solutions. Experimental results revealed that critical buckling temperature of the non-uniformly heated beam greatly differs from the uniformly heated beam. It is also observed that the location of heat source and resulting non-uniform temperature variation influences the critical buckling temperature significantly. © 2016 Elsevier Ltd
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    Buckling and dynamic characteristics of a laminated cylindrical panel under non-uniform thermal load
    (Techno Press technop2@chollian.net, 2016) Bhagat, V.; Jeyaraj, J.; Murigendrappa, S.M.
    Buckling and free vibration behavior of a laminated cylindrical panel exposed to non-uniform thermal load is addressed in the present study. The approach comprises of three portions, in the first portion, heat transfer analysis is carried out to compute the non-uniform temperature fields, whereas second portion consists of static analysis wherein stress fields due to thermal load is obtained, and the last portion consists of buckling and prestressed modal analyzes to capture the critical buckling temperature as well as first five natural frequencies and associated mode shapes. Finite element is used to perform the numerical investigation. The detailed parametric study is carried out to analyze the effect of nature of temperature variation across the panel, laminate sequence and structural boundary constraints on the buckling and free vibration behavior. The relation between the buckling temperature of the panel under uniform temperature field and non-uniform temperature field is established using magnification factor. Among four cases considered in this study for position of heat sources, highest magnification factor is observed at the forefront curved edge of the panel where heat source is placed. It is also observed that thermal buckling strength and buckling mode shapes are highly sensitive to nature of temperature field and the effect is significant for the above-mentioned temperature field. Furthermore, it is also observed that the panel with antisymmetric laminate has better buckling strength. Free vibration frequencies and the associated mode shapes are significantly influenced by the non-uniform temperature variations. © 2016 Techno-Press, Ltd.
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    Buckling and free vibration of nonuniformly heated functionally graded carbon nanotube reinforced polymer composite plate
    (World Scientific Publishing Co. Pte Ltd wspc@wspc.com.sg, 2017) George, N.; Jeyaraj, P.; Murigendrappa, S.M.
    Buckling and free vibration behavior of functionally graded carbon nanotube reinforced polymer composite plate subjected to nonuniform temperature fields have been investigated using finite element approach. The effective material constants of the plate are obtained using the extended rule of mixture along with efficiency parameters of the carbon nanotube (to include geometry-dependent material properties). Influence of boundary conditions, aspect ratio, functional grading of the carbon nanotube, nonuniform thermal loading on thermal buckling and free vibration behavior of the heated plate are analyzed. It is observed that temperature fields and functional grading are influenced on the critical buckling temperature of the plates. Further, nature of functional grading showed significant change in buckling mode shapes irrespective of the boundary conditions. The first few natural frequencies of the plate under thermal load decreases as the temperature increases and they are influenced significantly by the nature of temperature field. Variations in free vibration mode shapes of the square plates found with not significant change as temperature increases. However, free vibration modes of the rectangular plates are sensitive to the nature of temperature field whenever there is a free edge associated with the boundary condition. Influence of functional grading on the free vibration mode shapes is not significant in contrast with the free vibration natural frequencies. The magnitude of free vibration natural frequencies of functional grade-X type carbon nanotube reinforcement showed higher in comparison with other two types of reinforcements considered here. © 2017 World Scientific Publishing Company.
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    Experimental investigation on buckling strength of cylindrical panel: Effect of non-uniform temperature field
    (Elsevier Ltd, 2018) Bhagat, V.; Jeyaraj, P.
    Experimental investigation performed to evaluate buckling strength of a cylindrical panel exposed to non-uniform temperature field is presented. A novel experimental set-up developed in-house is used to evaluate buckling strength of a cylindrical panel made of Aluminum. Influence of nature of non-uniform temperature variation, structural boundary conditions and panel aspect ratio on buckling strength is investigated experimentally. Experimental results reveals that effect of nature of temperature field, resulting from the location of heat source, on buckling strength is significant. It is also observed that buckling strength is less when the least stiffness area of the panel is exposed to peak temperature of a particular temperature field. Similarly, CCCC boundary constraints results in high thermal stress which lowers the buckling strength of the panel as compared to CCFC boundary constraints. Temperature-deflection plot and corresponding buckling strength evaluated experimentally are compared with those obtained using non-linear finite element analysis, taking into account the initial geometric imperfection. © 2017 Elsevier Ltd
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    Nonuniform Heat Effects on Buckling of Laminated Composite Beam: Experimental Investigations
    (World Scientific Publishing Co. Pte Ltd wspc@wspc.com.sg, 2018) George, N.; Jeyaraj, P.
    The influence of nonuniform heating on the critical buckling temperature of laminated glass-epoxy composite beam has been investigated experimentally with the help of a novel experimental setup. The beam is numerically investigated using nonlinear finite element analysis. An initial geometric imperfection is introduced to the modeled geometry in numerical technique to have an experimental-numerical comparison of temperature-deflection plot. The results indicate that the critical buckling temperature of a uniformly heated beam has a significant difference in comparison to the nonuniformly heated beam and it depends on the heating source location and the resulting temperature distribution along the length direction of the beam. © 2018 World Scientific Publishing Company.
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    Thermal buckling of sisal and glass hybrid woven composites: Experimental investigation
    (Elsevier B.V., 2020) Gilorkar, A.; RAJESH, R.; Jeyaraj, J.
    The influence of hybridization of sisal woven fabric with glass fabric on thermal buckling behaviour of composite beam has been analysed experimentally. Initially, non-uniform heating (upward-downward, downward and downward-upward) has been achieved by positioning infrared (IR) heaters at the chosen locations along the longitudinal direction of the composite beam and deflection of the composite beam in the lateral direction measured through LabVIEW program and linear variable displacement transducer. Experiment results indicate that deflection behaviour of the beams under thermal load is entirely different from the deflection under mechanical load. The beams exhibited snap-through deflection behaviour with multiple inflection points due to the thermal load. Results revealed that the sisal woven fabric reinforced composite has high deflection under thermal load than hybrid composites. High elastic modulus and sandwiching effect as a result of hybridization provides more resistance against thermal deflection of the hybrid composites. Furthermore, the layering sequence and type of heating also influences the performance of the composites under thermal load. Results revealed that compared to cross ply sisal composite, an angle ply composite enhanced the resistance against deflection. Synergy effect of sandwiching and ply lay-up enhances resistance against deflection of the composite beams under non-uniform thermal load. © 2020