Conference Papers
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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.Item Effect of grooves on the static strength of tubular T joints of offshore jacket structures(Elsevier Ltd, 2019) Murugan, N.; Kaliveeran, V.; Nagaraj, M.K.The present research work deals with effect of grooves on static strength and stiffness of tubular T joints of offshore jacket structures. Tubular structures are commonly employed in offshore jacket platforms due to better mechanical properties and economic advantages. The tubular T model considered for this study has chord dimensions of 1000 mm length, diameter 102 mm and thickness 5 mm and brace dimensions of 388 mm length, diameter 55 mm and thickness 4 mm. Material used for present analysis is Steel with Young's modulus of 210 GPa and the Poisson ratio of 0.3. Three-dimensional finite element analysis has been carried out to investigate the effect of grooves placed over thickened chord section on the static strength of tubular T joints subjected to axial compressive load. In the present study, unstiffened tubular T joint is analysed and compared with stiffened tubular T joints to observe the improvement in the static strength of the tubular T joints. The groove configurations considered are: 5 circumferential grooves at 16.5 mm spacing, 3 circumferential grooves at 16.5 mm spacing and 3 circumferential grooves at 33 mm spacing. The grooves were having the dimension of 1 × 1 mm, 2 × 2 mm were used for the analysis. The joint local stiffness of ungrooved tubular T joint is 116.43 N/mm. The grooved configuration increases the joint local stiffness by more than 250 percent. © 2019 Elsevier Ltd. All rights reserved.Item Effective buckle arrestors for offshore pipelines(Elsevier Ltd, 2019) Ramachandra Rao, N.; Kaliveeran, V.Offshore pipelines are subjected to various forces, depending on the subsea conditions such as temperature, axial forces, pressure (internal and external), bending, and earthquake forces. The response of offshore pipelines in with-standing these forces involves elastic response as well as inelastic response. Buckle arrestors are installed at regular intervals along the length of the pipeline to prevent buckling occurring due to a combination of forces. Present research work focuses on the improvement in buckling strength of offshore pipelines which are stiffened with 3 different types of buckle arrestors. Buckling experiments were conducted on pipeline models fabricated from seamless stainless steel pipes of grade SS304. The pipeline models stiffened with three different buckle arrestors configurations; longitudinal continuous stiffener, sinusoidal stiffener, and angular stiffener. The purpose of our research is to study the effectiveness of buckle arrestor configuration in improving resistance to buckling and to identify optimum buckle arrestor configurations and their applicability to offshore pipelines. The study was conducted by finite element simulation of buckle arrestors using ANSYS. The stainless steel pipe models of 1 m length, 16 mm outer diameter, 11.8 mm inner diameter, 2.1 mm thickness are considered for finite element analysis and for conducting experiments. The results obtained from finite element analysis and experiment results show that the efficiency of buckle arrestor found to be more in case of pipeline stiffened with longitudinal continuous buckle arrestors. © 2019 Elsevier Ltd. All rights reserved.Item Analysis and design of inclined buckle arrestors for offshore pipeline(Elsevier Ltd, 2019) Ramachandra Rao, N.; Kaliveeran, V.Present research work focuses on improving buckling strength of offshore pipelines by strengthening them with inclined stiffeners and inclined stiffeners with connecting rods. Eigenvalue buckling analysis was carried out using Finite Element Methods to find the buckling strength of the considered pipeline models. Seamless stainless steel pipe models of SS304 grade were considered for finite element analysis. The pipeline models were provided with inclined stiffeners whose angle of inclination varies from 100° to 176°. Connecting rods of different lengths is used to improve capacity of inclined stiffeners. In this paper, the effect of inclined stiffener configurations in improving the strength of offshore pipelines against buckling is presented. The finite element analysis results show that a pipeline strengthened with inclined stiffeners and inclined stiffeners with connecting rod showed improved buckling load carrying capacity. © 2019 Elsevier Ltd. All rights reserved.Item Identification of effective location of thermocouples from the contact interface(Elsevier Ltd, 2019) Palanikumar, P.; Gnanasekaran, N.; Subrahmanya, K.; Kaliveeran, V.This paper describes an experimental and analytical investigation of the temperature rise at the contact interface which occurs during dry sliding of SS304 alloy. Experiments were conducted on rotatory type pin on disk tribometer. Cylindrical pin of 3 mm radius of contact and 165 mm diameter circular disk having flat surface were utilized to simulate Hertzian contact configuration. Rise in contact interface temperature due to sliding was measured using K-type thermocouples which are attached to the pin at 4 mm and 7 mm distance from the contact surface. The temperature at the contact surface during dry sliding experiment was calculated from the measured temperature data obtained from thermocouple pasted at 4 mm and 7 mm locations using inverse heat transfer method. Heat measured at different locations along the longitudinal axis of the pin increased with sliding distance. The temperature data obtained from finite element analysis is verified by comparing it with experimental results to identify effective location of thermocouples to measure the contact interface temperature. © 2019 Elsevier Ltd.Item Sliding of various ductile materials (Al 6061, Al 6082) using pin on disc setup(Elsevier Ltd, 2019) Srinivasula Reddy, I.; Kaliveeran, V.The present study focuses on understanding the variation of coefficient of friction over a period of time. At various sliding cycles, the coefficient of friction was noted from the well-controlled sliding experiments. Friction tests were conducted using Aluminium alloys (Al 6061 and Al 6082) with 10 N constant normal load and at sliding speed of 1.5 m/s. The detailed friction results have been presented and discussed to understand the influence of coefficient of friction on the contact tractions at the interface. The obtained friction results are compared with the results mentioned in literature, where reciprocating sliding experiments were conducted. From this comparison, it is concluded that the formation of oxide and nitride layers are dominant, when the friction tests are conducted using pin on disc setup. © 2019 Elsevier Ltd. All rights reserved.