Faculty Publications
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Item 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.Item 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. © 2020Item Free vibration modes of rectangular plate under non-uniform heating: An experimental investigation(Elsevier Ltd, 2020) Twinkle, C.M.; Jeyaraj, J.; Vasudevan, V.Experimental studies carried out to investigate the influence of local heating on vibration mode shapes of an isotropic plate are presented. Different types of temperature fields were created by keeping the heating source at different locations. The deflection vs temperature curve is used to estimate the critical buckling temperature of the plate using inflection point method. The plate was exposed to different levels of elevated temperature as a function of buckling temperature and natural frequencies and mode shapes of the plate are estimated experimentally. Experimental investigation revealed that the effect of heating on vibration modes of the plate is significant. With the increase in elevated temperature, decrease in free vibration frequencies, shifting of nodal and anti-nodal positions and jumping of the modes are observed clearly. Experimental results associated with temperature vs deflection curve, natural frequencies and mode shapes at elevated temperature are compared with numerical results based on finite element method and found that the results are in good agreement. © 2020 Institution of Structural EngineersItem Thermal buckling and vibro-acoustic behaviour of functionally graded graphene polymer layered composites subjected to in-plane temperature variance(SAGE Publications Ltd, 2022) John, B.O.; Hassan, F.U.; George, N.; Chacko, T.; Bhagat, V.S.; Jeyaraj, J.; Kiran Kumar Reddy, R.The current study reports the thermal buckling, vibration and acoustic characteristics of functionally graded graphene polymer layer composite plates subjected to the in-plane temperature variance. The macroscopic properties of the composites are evaluated using the modified rule of mixtures to compute the layer-wise properties of an functionally graded graphene polymer layer composite plate. The critical buckling temperature is computed and compared for various functional gradings, boundary conditions and in-plane temperature variances. The in-plane temperature variance showed a major impact on the critical thermal buckling temperature and respective mode shapes. The vibro-acoustic behaviour of the functionally graded graphene polymer layer composite plate is investigated and documented keeping critical buckling temperature as a function. With an increase in thermal load and the nature of in-plane temperature variance, the vibro-acoustic results showed significant difference in velocity and acoustic response. For functionally graded graphene polymer layer composite plate with one free edge, the difference was statistically significant as indicated by an octave band plot. We conclude that the portion of the functionally graded graphene polymer layer composite plate that is subjected to the higher temperature in an in-plane temperature variance, as well as the nature of the boundary conditions may exacerbate the effect of in-plane temperature variance and are crucial in predicting vibro-acoustic characteristics. © IMechE 2022.Item Buckling behavior of non-uniformly heated 3D printed plain and functionally graded nanocomposites(John Wiley and Sons Inc, 2023) Kumar, S.; Ramesh, M.R.; Jeyaraj, J.; Powar, S.; Doddamani, M.The functionalized multi-walled carbon nanotubes (MWCNTs) (0.5–5 wt.%) are compounded with high density polyethylene (HDPE), and, subsequently, used for extruding nanocomposite filaments to fabricate nanocomposites (NCs) and functionally graded nanocomposites (FGNCs) through 3D printing. The 3D printed NCs are investigated for coefficient of thermal expansion (CTE), and buckling under different non-uniform temperature distributions (case-1: left edge heating, case-2: centre heating, and case-3: left and right edge heating). A significant reduction in CTE is observed with MWCNT addition and gradation. The highest reduction in CTE is observed for H5 (5 wt.% of MWCNT in HDPE) NC and H1 ⟶ H3 ⟶ H5 (FGNC-2) among the NCs and the FGNCs. It is noted that Tcr (critical buckling temperature) is highest for case-3 and lowest for case-2. The highest deflection is noticed in case-2, while no significant difference is observed in case-1 and case-3 heating conditions. It is also observed that Tcr increases with gradation and MWCNTs addition. The H5 NC and FGNC-2 exhibited the highest Tcr among the NCs and FGNCs, respectively. The maximum deflection is noticed for HDPE, whereas the minimum deflection is noticed for FGNC-2 and H-5 NC among the tested samples. The results also revealed that Tcr is very sensitive to type of heating. © 2023 Society of Plastics Engineers.