Faculty Publications

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Subject: search.filters.subject.Nonuniform temperature

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    Buckling and vibration behavior of a non-uniformly heated isotropic cylindrical panel
    (Techno-Press, 2016) Bhagat, V.S.; Jeyaraj, P.; Murigendrappa, S.M.
    This study attempts to address the buckling and free vibration characteristics of an isotropic cylindrical panel subjected to non-uniform temperature rise using numerical approach. Finite element analysis has been used in the present study. The approach involves three parts, in the first part non-uniform temperature field is obtained using heat transfer analysis, in the second part, the stress field is computed under the thermal load using static condition and, the last part, the buckling and pre-stressed modal analysis are carried out to compute critical buckling temperature as well as natural frequencies and associated mode shapes. In the present study, the effect of non-uniform temperature field, heat sink temperatures and in-plane boundary constraints are considered. The relation between buckling temperature under uniform and non-uniform temperature fields has been established. Results revealed that decrease (Case (ii)) type temperature variation field influences the fundamental buckling mode shape significantly. Further, it is observed that natural frequencies under free vibration state, decreases as temperature increases. However, the reduction is significantly higher for the lowest natural frequency. It is also found that, with an increase in temperature, nodal and anti-nodal positions of free vibration mode shapes is shifting towards the location where the intensity of the heat source is high and structural stiffness is low. © © 2016 Techno-Press, Ltd.
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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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    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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    Structural behavior of fg-cnt cylindrical panel: Influence of non-uniform temperature field
    (Institute for Problems in Mechanical Engineering, Russian Academy of Sciences, 2020) Bhagat, V.; Jeyaraj, J.
    In this study, the influence of non-uniform temperature field and temperature-dependent properties on buckling and free vibration behavior of functionally graded carbon nanotube (FG-CNT) reinforced composite cylindrical panel is investigated. For the structural analysis, the finite element method and modal assurance criterion (MAC) analysis are performed. It is found that the temperature-dependent properties and nature of temperature variation fields affect the thermal buckling strength of the panel greatly. The results from MAC analysis reveals that the influence of temperature and nature of temperature variation on buckling and free vibration modes are significant. Further, it is also found that variations in frequencies and associated modes are significant at a temperature closer to buckling temperature. © 2020, Peter the Great St. Petersburg Polytechnic University
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    Sound radiation characteristics of a beam under supersonic airflow and non-uniform temperature field
    (Elsevier Masson s.r.l., 2024) Patil, H.H.; Pitchaimani, J.
    This paper investigates vibro-acoustic behaviour of an isotropic beam subjected to in-plane varying temperature field and supersonic flow. For a given elevated temperature and non-uniform temperature (NUFT) field, the aerodynamic pressure (ADP) is varied in fraction of its critical value, and the consequent effect on sound radiation characteristics is investigated. Shear and normal deformable beam theory (SNDBT) based kinematics is used, and equations of motion are obtained using Hamilton's principle. Following that, the Ritz method is used to solve the equations. To start with, aeroelastic flutter and vibro-acoustic response characteristics (as a function of critical aerodynamic pressure (λcr)) are analyzed without considering any thermal stress effect. Following that, for a given temperature field, the critical buckling temperature (ΔTcr) of the beam is obtained. Then, the impact of thermal stress caused by the NUFT field on the flutter and sound radiation characteristics is studied. The study observed that the combined effects of the NUFT field and variable ADP significantly impacted the beam's flutter and vibro-acoustic responses. © 2024 Elsevier Masson SAS
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    Nonlinear buckling and free vibration analysis of auxetic graphene origami composite beams under nonuniform thermal environment
    (Taylor and Francis Ltd., 2025) Shashiraj; Pitchaimani, J.; Kattimani, S.
    This study examines the thermo-mechanical behavior of auxetic metamaterial beams enhanced by graphene origami (GOri) under spatially varying nonuniform temperature distributions (SVTD). Utilizing Timoshenko beam theory considering von-Kármánn type nonlinear strain–displacement relationship, GOri beams are modeled as layered structures. The Ritz method is employed to solve equilibrium equations, analyzing the impact of GOri distribution patterns, content, and folding degree on post-buckling and vibration paths. The effects of five SVTDs, three end conditions, and three GOri distribution patterns on buckling, post-buckling behavior, and nonlinear free vibration characteristics are explored. Findings reveal that the parabolic temperature distribution with peak temperatures at beam ends (P-MAE) results in higher critical temperatures and nonlinear free vibration frequencies. This research provides crucial insights into the design and optimization of GOri-enabled metamaterial structures in complex thermal environments, highlighting the significant influence of nonuniform temperature distributions along the beam’s length. © 2024 Taylor & Francis Group, LLC.
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    Thermoelastic buckling and vibration analysis of shear and normal deformable three-phase bio-inspired composite beams under axially varying temperature fields
    (Springer, 2025) Patil, H.H.; Pitchaimani, J.
    The thermoelastic buckling and free vibration behaviors of a Three-Phase Composite (TPC) beam subjected to axially varying Non-Uniform Temperature (NUFT) fields is investigated by incorporating Temperature-Dependent (TD) elastic properties of both Carbon Nanotubes (CNTs) and the matrix. The Shear and Normal Deformable Beam Theory (SNDBT) is used to model the kinematics, and the governing equations are formulated through Hamilton’s principle and solved using the Ritz method. TD elastic properties of CNTs are accounted in terms of TD Hill’s constants. Dispersion issue of CNT is accounted in terms of partial and complete agglomeration effects for more realistic material modeling. The results indicate that the area beneath the NUFT distribution profiles serves as a meaningful parameter for interpreting both the critical buckling temperature (?Tcr) and the induced axial membrane force (N). NUFT-induced differential thermal expansion generates localized thermal strain variations, and the strain reverses its sign whenever the temperature at a point exceeds the spatially averaged temperature for the given NUFT. Consideration of thickness-stretching deformation (Wz) produces noticeable changes in ?Tcr and the fundamental frequency (?1), particularly for the beams with lower aspect-ratio, emphasizing its necessity in thick-beam modeling. The findings provide practical guidance for the design of lightweight, thermally stable composite structures deployed in aerospace and other thermal-environment-critical engineering systems. © The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2025.