Faculty Publications
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Item Structural Analysis of Non-prismatic Column Using Finite Element Approach(Springer, 2024) Kumar, G.; Kaliveeran, V.Offshore pipelines are subjected to various types of loading, depending upon the sub-sea conditions during their design life. Buckling is a major structural instability problem in the offshore pipelines operating at high pressure and high temperature, along with other causes. Various kinds of non-prismatic sections are generally used in special areas of the pipeline system. The present research work focuses on estimating the structural response (bucking strength, in particular) of the non-prismatic offshore pipelines. Eigenvalue buckling analysis using the Finite Element (FE) method was conducted to find the buckling strength and mode shape of the pipeline model. The non-prismatic pipeline was modeled as 1-D and 3-D FE models; the 1-D model was analyzed using the MATLAB program, and the complete 3-D model was analyzed using the ANSYS workbench. Both the 1-D and 3-D numerical analysis results were compared and verified experimentally. The results of the analysis and their convergence pattern were also discussed. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Stress Analysis of a Member of Jacket Structure with Different Types of Stiffeners(Springer, 2024) Sreejith, T.S.; Kaliveeran, V.Jacket structures are subjected to very challenging environmental conditions and thus require certain reinforcements to ensure the resistance against the challenging conditions. The present study deals with the stress analysis of a member of a jacket structure with triangular type stiffener and another with second order curved stiffener. The specimen considered is of steel with dimensions 800 mm × 100 mm × 10 mm. The member is considered as a fixed bar subjected to a concentrated load of 500 N at the mid-span. The idea is to reinforce the member to strengthen up which in turn increases the life of the structure. The configuration of the stiffeners is such that the stress concentration is avoided. The triangular stiffener has a length of 200 mm and height of 20 mm and thickness of 10 mm. The second order curved stiffener has the same length, height and thickness and follows the variation y=20-x5+x22000. Four stiffeners are provided, one at the top and one at the bottom of each end. The structure is simulated and analyzed in a Finite Element Modelling (FEM) software and the necessary results are obtained. The results from this analysis are validated using the experimental results. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Stress Analysis of Thin Rectangular Sections Subjected to Twisting Moment(Springer, 2024) Joshi, S.V.; Kaliveeran, V.The major issue in the stress analysis of thin sections is the stress concentration on the edges, especially the sharp edges. Whilst analysing thin sections for any analysis, be it flexural, torsional, axial etc., the phenomenon of sharp edge stress concentration reduces the quality of results of the analysis. Thus, it becomes necessary to determine the particular loading orientations in order to study the analysis in its purest form without the interventions of other unnecessary behaviours. The present study is about the stress analysis of thin rectangular section, when it is subjected to a twisting moment. A thin rectangular member of dimensions, length = 100 mm, depth = 40 mm, and width = 1 mm is considered with one end of the length as fixed and the other end as free. A torque of magnitude 0.1 Nmm is applied at the free end. Initially, a theoretical analysis is done and the point of maximum shear stress is determined. Then numerical analysis of the same is done on an FEM modelling software with different combinations of loadings in the form of a twisting moment. The determination of the exact load orientation which simulates the pure torsional moment behaviour for a thin rectangular section is the main objective of this study. The results obtained by FEM modelling on the software are validated theoretically and experimentally. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Experimental Investigation of the Behavior of Tubular T-Joint of Jacket Structures(Springer, 2024) Murugan, N.; Kaliveeran, V.; Kundapura, S.This study deals with a preliminary experimental study to examine the behavior of tubular T-joint of Jacket structures under compressive load, which is helpful for further study of reinforcement in T-joints for strengthening. A specimen of T-joint with geometric dimensions of chord length = 494 mm, chord diameter = 141 mm, chord thickness = 5 mm, and brace length = 237 mm, brace diameter = 90 mm, brace thickness = 4.5 mm was considered for this study. The specimen is subjected to axial compressive load which is applied from the top end of the brace member. The ends of the chord member are in simply supported condition. The experiment is conducted in a 40 T UTM machine. The loads are applied with an interval of 50 kgf starting from zero to the yield load of 9,600 kgf. The experimental setup, specimen details, and the relevant results (load-deformation relationship and failure mechanism) are presented. The findings of the study, i.e., local joint deformation behavior under compressive load, are presented graphically. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Finite Element Modelling and Experimental Validation of Strain Gauge Pasted Over the Surface of a Substrate Subjected to a Transverse Load(Springer, 2024) Raveesh, R.M.; Kaliveeran, V.; Kundapura, S.The strain measurement is important as it directly involves with the deformation of a structure in the field of engineering. Strain is a measure of change in shape that occurs when an external load is applied to an engineering assembly. The evaluation of the strain is used to determine the amount of extension or deformation a structure experiences under different loading conditions. Strain gauges are electrical resistance sensors bonded at critical locations on the surface of structural components to detect surface deformation. Strain gauges are frequently used to continuously check for deformations to avoid accidents that can occur in nuclear power plants, aerospace vehicles, mechanical components, and structures. Strain gauges applied directly to the specimen are partially affected by the bonding material and thickness when tested. Present work intends to study the effect of adhesive thickness on strain values. Adhesives are used to paste strain gauges over the surface of the specimen. Three-Dimensional analysis of the strain gauge model has been carried out with the aid of the Finite element software. Experiments were conducted to study the effect of adhesive thickness by varying the thickness of the adhesive from 0.1 to 1 mm by pasting strain gauge over the surface of the Aluminium specimen of length 230 mm, width of 30 mm, and thickness of 6 mm. The strain values obtained from the finite element analysis were compared with the strain values obtained from the experiments. Finite element analysis results were found to be in good correlation with the experimental results. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Dry sliding friction and wear of Al 6061 and Al 6082 alloys under different normal loads(Elsevier Ltd, 2019) Srinivasula Reddy, I.; Kaliveeran, V.The current research work addresses evolution of coefficient of friction over sliding distance. Friction and wear tests were conducted using pin on disk type tribometer. The stabilized friction coefficient values under normal load of 10 N and 15 N for Al 6061 were noted as 0.5 and 0.58 respectively. Corresponding friction coefficient values for Al 6082 were noted as 0.6 and 0.45 respectively. Equation to calculate wear volume was derived for cylinder on flat contact. The dominant wear mechanisms were justified with the images of the disk specimens captured using optical microscope. Increase in wear volume resulting from increase in normal load was observed for Al 6061 and Al 6082 alloys. © 2019 Elsevier Ltd. All rights reserved.Item Flexural modulus of epoxy composite reinforced with Arecanut husk fibre (AHF): A mechanics approach(Elsevier Ltd, 2019) Muralidhar, N.; Kaliveeran, V.; Arumugam, V.; Srinivasula Reddy, I.Arecanut Husk Fibre (AHF) is an agricultural waste material. Polymer composites prepared with AHF as reinforcing material avoids dumping of arecanut husk onto bare land. AHF contributes to the development of innovative products having low environmental impact. These polymer composites are cost-effective and have low-density. Composites manufactured using polymers and natural fibre are widely used in aerospace, automobile, construction and marine structural applications. AHF was extracted by chemical retting process using 6% sodium hydroxide solution. The present research focuses on composite panel preparation using epoxy reinforced with treated AHF (15% by weight of composite) and flexural characterization of the composite. Composites were made with three-layered arrangement of AHF threads. In the current study, flexural modulus of AHF composite panels is determined by conducting dynamic flexural tests with fixed-fixed support condition and at different loading frequencies. The flexural modulus of the composite material is calculated using Euler-Bernoulli bending theory and results are compared with existing literature. © 2019 Elsevier Ltd. All rights reserved.Item Finite element analysis of rig used for fretting experiments(Elsevier Ltd, 2019) Raja Pandi, R.; Kaliveeran, V.Fretting is a damage mechanism which occurs between two tightly clamped components when these two components are subjected to very small amplitude of relative motion. Design and fabrication of fretting rig is essential to conduct fretting tests. The fretting rig has been used to clamp the pads onto the specimen. While conducting the fretting experiments, the normal load was applied through the pads and frictional force was generated at the contact interface between the pad and the specimen. Fretting experiments were conducted with a cyclic load which involves a stress ratio ('R' ratio). To decide 'R' ratio, we need to understand the load transfer ratio (LTR). LTR is the ratio between the load transferred to the top of the specimen and the load applied to the bottom of the specimen. LTR value should be optimum to conduct fretting experiments. So, the fretting rig which produces least LTR value (close to 50%) can be used as rig in fretting experiments. To ensure this condition, initially eleven cases of simple one-dimensional (1-D) fretting rig models have been designed and Finite Element (FE) analysis of these models was carried out. Afterwards four more different fretting rig models have been designed and analyzed with the inclusion of machine constraints and its results are also presented here. Among these models, the finite element model with optimum LTR was selected to conduct fretting experiments and the detailed three-dimensional (3-D) finite element study of the selected model has been performed and its results were validated with one-dimensional finite element analysis results. © 2019 Elsevier Ltd. All rights reserved.Item Effect of sliding speed and rise in temperature at the contact interface on coefficient of friction during full sliding of SS304(Elsevier Ltd, 2019) Palanikumar, P.; Gnanasekaran, N.; Subrahmanya, K.; Kaliveeran, V.The present study focuses on the effect of sliding speed and rise in temperature on the coefficient of friction at the contact interface of SS304 alloys subjected to full sliding. Dry sliding experiments were conducted on Rotatory Type Pin on Disk Tribometer. Pins of 3 mm radius and 165 mm diameter circular disk having flat surface were fabricated to simulate Hertzian contact configuration. Experiments were conducted at three different sliding speeds of 1 m/s, 2 m/s and 3 m/s under constant normal load of 1 kg. All the experiments were conducted up to sliding distance of 100 m. From the full sliding experiments, the coefficient of friction decreased with increase in sliding speed and the stabilized coefficient of friction for SS304 alloy was in the range of 0.15-0.28. The temperatures due to friction were measured using K-type thermocouples and they were located to the pins at 4 mm and 7 mm distance from the contact surface. The temperature at the contact surface during dry sliding experiment was obtained from the acquired data using inverse heat transfer method. Temperature measured at different locations along the longitudinal axis of the pin increased with increase in sliding speed and sliding distance. The increase in temperature at the contact interface was observed due to increase in friction at the contact interface during sliding. The temperature had shown stabilized trend, when the coefficient of friction curve got stabilized during sliding process. © 2019 Elsevier Ltd.Item Finite element modeling and experimental validation of rectangular pin buckle arrestors for offshore pipelines(Elsevier Ltd, 2019) Ramachandra Rao, N.; Kaliveeran, V.Offshore pipelines used for transportation of hydrocarbons in the oil industry are subjected to external pressure, internal pressure to ensure flow, temperature and axial compression which causes buckling. Finite element modeling was performed, and experiments were conducted on pipeline models made of stainless steel of grade SS304. Present research work focuses on the improvement in buckling strength of offshore pipelines stiffened with rectangular pin buckle arrestor along the length of a pipeline using finite element analysis and their experimental validation. The results of finite element analysis showed that an offshore pipeline model without buckle arrestors has a buckling load of 4.69 kN whereas offshore pipeline stiffened with buckle arrestors of length 1000 mm along the length of a pipeline resulted in maximum buckling load of 14.075 kN. Accordingly, pipeline models were fabricated for conducting experiments. Comparison of finite element analysis results and experimental outcomes showed that the efficiency of buckle arrestor increased significantly by incorporating buckle arrestor along the length of a pipeline. © 2019 Elsevier Ltd. All rights reserved.