Browsing by Author "Subrahmanya, K."

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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. Â© 2019 Elsevier Ltd.
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. Â© 2019 Elsevier Ltd.
Stability aspects of nonreshaped berm breakwaters with reduced armor weight
(2008) Rao, S.; Subrahmanya, K.; Rao, B.K.; Chandramohan, V.R.
The present work involves the investigation of the influence of wave height, wave period, water depth, and sea-ward slope on the stability, wave runup, and wave rundown of statically stable rubble-mound berm breakwater. The weight of armor stones used in the present study is 20% lighter than the weight that is required for a conventional breakwater, designed using Hudson formula for a wave height of 0.1 m in the model. In the present work models with a berm width of 0.6 m, at constant depth of 0.32 m from the seabed were tested. The damage to the breakwater model with the berm was compared with the results on a model without the berm using different armor weights. The variation of relative runup and rundown was found for different values of wave steepness and water depths in front of the structure. The damage to the breakwater, wave runup, and rundown for the structure with seaward slope 1:2 and 1:1.5 were compared. The investigation was carried out in the Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, Surathkal. 2008 ASCE.
Stability aspects of nonreshaped berm breakwaters with reduced armor weight
(2008) Rao, S.; Subrahmanya, K.; Balakrishna Rao, B.K.; Chandramohan, V.R.
The present work involves the investigation of the influence of wave height, wave period, water depth, and sea-ward slope on the stability, wave runup, and wave rundown of statically stable rubble-mound berm breakwater. The weight of armor stones used in the present study is 20% lighter than the weight that is required for a conventional breakwater, designed using Hudson formula for a wave height of 0.1 m in the model. In the present work models with a berm width of 0.6 m, at constant depth of 0.32 m from the seabed were tested. The damage to the breakwater model with the berm was compared with the results on a model without the berm using different armor weights. The variation of relative runup and rundown was found for different values of wave steepness and water depths in front of the structure. The damage to the breakwater, wave runup, and rundown for the structure with seaward slope 1:2 and 1:1.5 were compared. The investigation was carried out in the Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, National Institute of Technology Karnataka, Surathkal. © 2008 ASCE.
This paper presents the results of the experimental investigation of the stability, wave runup and rundown characteristics of the statically stable berm breakwater with a wide berm. Armour weight calculated using Hudson's formula for design wave height has been reduced to an extent of 20% in the present study. The variations of non-dimensional runup values (Rd/Ho) and the rundown values (Rd/Ho) with deep- water wave steepness (Ho/gT2), damage level (S) with stability number (Ns) are investigated for different depths of still water level (SWL). A decrease in runup and rundown with wave steepness has been observed. Location of berm near SWL has been found to be more effective in reducing the wave runup. Damage level increases with decrease in wave period within the limits of experimental variables studied. © 2005 Taylor & Francis Group, LLC.
(Wave runup, rundown and stability analysis on berm breakwater with 20% reduced armour weight) Rao, S.; Subrahmanya, K.; Balakrishna Rao, K.B.; Chandramohan, V.R.
2005
Wave runup, rundown and stability analysis on berm breakwater with 20% reduced armour weight
(2005) Rao, S.; Subrahmanya, K.; Rao, K.B.; Chandramohan, V.R.
This paper presents the results of the experimental investigation of the stability, wave runup and rundown characteristics of the statically stable berm breakwater with a wide berm. Armour weight calculated using Hudson's formula for design wave height has been reduced to an extent of 20% in the present study. The variations of non-dimensional runup values (Rd/Ho) and the rundown values (Rd/Ho) with deep- water wave steepness (Ho/gT2), damage level (S) with stability number (Ns) are investigated for different depths of still water level (SWL). A decrease in runup and rundown with wave steepness has been observed. Location of berm near SWL has been found to be more effective in reducing the wave runup. Damage level increases with decrease in wave period within the limits of experimental variables studied. � 2005 Taylor & Francis Group, LLC.