The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Manish Verma - One of the best experts on this subject based on the ideXlab platform.
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tribological study of elastomeric bearings for marine Propeller Shaft system
Tribology International, 2009Co-Authors: Harish Hirani, Manish VermaAbstract:Abstract Elastomeric compounds, due to their favourable properties like sufficient hardness, toughness and natural resistance to abrasion and corrosion, are commonly used as bearing material for Propeller Shaft system of Indian Coast Guard Ships. Recently unequal and non-uniform wear of these bearings has resulted in unscheduled lay off of the Coast Guard Ships. To solve this problem of bearing wear, a mixed lubrication analysis of sea-water lubricated journal bearing has been attempted in the present study. A computer code was written to estimate lubricating film thickness for a given set of load and speed condition, and to predict the lubrication regime for the specified surface roughness parameters. To validate the theoretical analysis performed in the present study, the results obtained from the computer simulation have been compared with the established studies on the water lubricated bearing. To understand the uneven wear of marine bearings, actual geometric clearances of new and worn out bearings recorded by the ship maintenance team, and the operational data (load, speed and operating hours), obtained from the log books of ICGS Sangram (AOPV) of Indian Coast Guard, are listed in the present paper. The dynamic viscosity of sea water, surface roughness of Propeller Shaft and bearings, and particulate contamination has been measured. Finally, the suggestions have been enlisted for proper operation of Shaft-bearing system so as to maintain the wear within the permissible limits during ship's operational cycle.
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Tribological study of elastomeric bearings for marine Propeller Shaft system
Tribology International, 2009Co-Authors: Harish Hirani, Manish VermaAbstract:Elastomeric compounds, due to their favourable properties like sufficient hardness, toughness and natural resistance to abrasion and corrosion, are commonly used as bearing material for Propeller Shaft system of Indian Coast Guard Ships. Recently unequal and non-uniform wear of these bearings has resulted in unscheduled lay off of the Coast Guard Ships. To solve this problem of bearing wear, a mixed lubrication analysis of sea-water lubricated journal bearing has been attempted in the present study. A computer code was written to estimate lubricating film thickness for a given set of load and speed condition, and to predict the lubrication regime for the specified surface roughness parameters. To validate the theoretical analysis performed in the present study, the results obtained from the computer simulation have been compared with the established studies on the water lubricated bearing. To understand the uneven wear of marine bearings, actual geometric clearances of new and worn out bearings recorded by the ship maintenance team, and the operational data (load, speed and operating hours), obtained from the log books of ICGS Sangram (AOPV) of Indian Coast Guard, are listed in the present paper. The dynamic viscosity of sea water, surface roughness of Propeller Shaft and bearings, and particulate contamination has been measured. Finally, the suggestions have been enlisted for proper operation of Shaft-bearing system so as to maintain the wear within the permissible limits during ship's operational cycle. © 2008 Elsevier Ltd. All rights reserved.
Alfayo A Alugongo - One of the best experts on this subject based on the ideXlab platform.
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parametric excitation and wavelet transform analysis of a ground vehicle Propeller Shaft
Journal of Vibration and Control, 2014Co-Authors: Alfayo A AlugongoAbstract:This paper proposes a numerical model for analyzing torsional vibration of a ground vehicle Propeller Shaft system. By considering the elasticity and energy of the Propeller system, a Lagrangian ap...
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A nonlinear torsional vibration model of a Propeller Shaft with a crack-induced parametric excitation and a hookes joint type of kinematic constraint
IEEE Africon '11, 2011Co-Authors: Alfayo A AlugongoAbstract:In this paper, a model for analyzing torsional vibration of a ground vehicle Propeller Shaft system has been proposed. The model takes into account dynamics of a Hooke's joint and a crack-induced parametric excitation. By considering torsional vibration and Energy of the Propeller, a Lagrangian approach has been used to derive the equation of motion yielding a highly nonlinear 3-DOF system with four coupled inertias. Subsequently, nonstationary response of the system has been characterized by a wavelet technique. The system vibration response in various scenarios has been evaluated and reported. Obtained results concur with existing literature. By analysis it is demonstrated that, the model is good for investigating nonlinear vibration of a typical Propeller Shaft system used in light ground vehicles.
Harish Hirani - One of the best experts on this subject based on the ideXlab platform.
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tribological study of elastomeric bearings for marine Propeller Shaft system
Tribology International, 2009Co-Authors: Harish Hirani, Manish VermaAbstract:Abstract Elastomeric compounds, due to their favourable properties like sufficient hardness, toughness and natural resistance to abrasion and corrosion, are commonly used as bearing material for Propeller Shaft system of Indian Coast Guard Ships. Recently unequal and non-uniform wear of these bearings has resulted in unscheduled lay off of the Coast Guard Ships. To solve this problem of bearing wear, a mixed lubrication analysis of sea-water lubricated journal bearing has been attempted in the present study. A computer code was written to estimate lubricating film thickness for a given set of load and speed condition, and to predict the lubrication regime for the specified surface roughness parameters. To validate the theoretical analysis performed in the present study, the results obtained from the computer simulation have been compared with the established studies on the water lubricated bearing. To understand the uneven wear of marine bearings, actual geometric clearances of new and worn out bearings recorded by the ship maintenance team, and the operational data (load, speed and operating hours), obtained from the log books of ICGS Sangram (AOPV) of Indian Coast Guard, are listed in the present paper. The dynamic viscosity of sea water, surface roughness of Propeller Shaft and bearings, and particulate contamination has been measured. Finally, the suggestions have been enlisted for proper operation of Shaft-bearing system so as to maintain the wear within the permissible limits during ship's operational cycle.
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Tribological study of elastomeric bearings for marine Propeller Shaft system
Tribology International, 2009Co-Authors: Harish Hirani, Manish VermaAbstract:Elastomeric compounds, due to their favourable properties like sufficient hardness, toughness and natural resistance to abrasion and corrosion, are commonly used as bearing material for Propeller Shaft system of Indian Coast Guard Ships. Recently unequal and non-uniform wear of these bearings has resulted in unscheduled lay off of the Coast Guard Ships. To solve this problem of bearing wear, a mixed lubrication analysis of sea-water lubricated journal bearing has been attempted in the present study. A computer code was written to estimate lubricating film thickness for a given set of load and speed condition, and to predict the lubrication regime for the specified surface roughness parameters. To validate the theoretical analysis performed in the present study, the results obtained from the computer simulation have been compared with the established studies on the water lubricated bearing. To understand the uneven wear of marine bearings, actual geometric clearances of new and worn out bearings recorded by the ship maintenance team, and the operational data (load, speed and operating hours), obtained from the log books of ICGS Sangram (AOPV) of Indian Coast Guard, are listed in the present paper. The dynamic viscosity of sea water, surface roughness of Propeller Shaft and bearings, and particulate contamination has been measured. Finally, the suggestions have been enlisted for proper operation of Shaft-bearing system so as to maintain the wear within the permissible limits during ship's operational cycle. © 2008 Elsevier Ltd. All rights reserved.
W. Litwin - One of the best experts on this subject based on the ideXlab platform.
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influence of main design parameters of ship Propeller Shaft water lubricated bearings on their properties
Polish Maritime Research, 2010Co-Authors: W. LitwinAbstract:In recent years more and more frequently can be met ships in which Propeller Shaft water-lubricated polymer bearings have been applied. It results from their simplicity and associated relatively low initial and operational cost as compared with the complex classical sealed system based on oil-lubricated bearings. It is worth mentioning that the water-lubricated bearings are also environmentally friendly as no risk of pollution with lubricating oil used in classical systems, is involved. Design procedure of bearings in question based on materials made available by producers is relatively simple. However it turns out that choice of an appropriate sliding material, clearance value and optimum arrangement of lubricating grooves may greatly influence bearing’s properties. As results from the performed research investigations, bearing of the kind is a highly sensitive unit. Problems of choosing a suitable bearing clearance, designing an optimum bush geometry, selecting a proper bush material are crucial for life time of the bearing. In particular the problem is in forming hydrodynamical properties of bearing as owing to its operation in the fluid friction regime durability of bearings, the very responsible units of propulsion transmission system, can be greatly extended.
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Water lubricated hybrid Propeller Shaft with polymer bearing bush
Proceedings of the World Tribology Congress III - 2005, 2005Co-Authors: W. LitwinAbstract:The article deals with water lubricated hybrid marine Propeller Shaft bearing which was designed and built at the Faculty of Ocean Engineering and Ship Technology of the Gdansk (Poland) University of Technology. The article contains the following parts: Description of the test stand, the simulated working conditions, and tested bearings' specifications. Results of the conducted measurements. The results of the experimental work include: graphs of friction coefficient, pressures in the water hydrodynamic film and Shaft trajectory. Comparison of hybrid bearing with two others bearings. Typical main Shaft bearing with grooved bearing bush working in a semi fluid friction conditions and hydrodynamic bearing with cull bearing bush (without any grooves). The work's essential conclusion is that fluid film lubrication is possible also in hybrid bearings with grooves. As it was proven under simulated working conditions hydrodynamic lubrication does not take place in typical bearing with grooved bearing bush. Copyright © 2005 by ASME.
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water lubricated hybrid Propeller Shaft bearings with polymer bearing bush
World Tribology Congress III Volume 2, 2005Co-Authors: W. LitwinAbstract:The article deals with water lubricated hybrid marine Propeller Shaft bearing which was designed and built at the Faculty of Ocean Engineering and Ship Technology of the Gdansk (Poland) University of Technology. The article contains the following parts: • Description of the test stand, the simulated working conditions, and tested bearings’ specifications. • Results of the conducted measurements. The results of the experimental work include: graphs of friction coefficient, pressures in the water hydrodynamic film and Shaft trajectory. • Comparison of hybrid bearing with two others bearings. Typical main Shaft bearing with grooved bearing bush working in a semi fluid friction conditions and hydrodynamic bearing with cull bearing bush (without any grooves). The work’s essential conclusion is that fluid film lubrication is possible also in hybrid bearings with grooves. As it was proven under simulated working conditions hydrodynamic lubrication does not take place in typical bearing with grooved bearing bush.Copyright © 2005 by ASME
M X Shen - One of the best experts on this subject based on the ideXlab platform.
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acoustic and vibrational characteristics of a Propeller Shaft hull coupled system based on sono elasticity theory
Journal of Vibration and Control, 2018Co-Authors: L B Qi, Y S Wu, Yong Duan, M X ShenAbstract:The three-dimensional sono-elasticity method recently developed by Zou ((2014) Three-dimensional sono-elasticity of ships. PhD Dissertation, China Ship Scientific Research Center, China) and Wu ((1984) Hydroelasticity of floating bodies. PhD Dissertation, Brunel University, UK) is employed to explore the acoustic and vibrational characteristics of a Propeller–Shaft–hull coupled system. The acoustic field can be solved by introducing Green’s function for the ideal compressible fluid together with the Price–Wu generalized fluid–structure interface boundary conditions. The vibration of a ship structure is governed by the generalized equations, including added mass, damping and restoring coefficients. In order to discover the mechanisms underlying the acoustic and vibrational characteristics of the Propeller–Shaft–hull coupled system, numerical models for hull structures with a Shaft and without a Shaft are designated. Through modal analysis, the correlations of the line spectra of acoustic radiation and the ...
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Acoustic and vibrational characteristics of a Propeller–Shaft–hull coupled system based on sono-elasticity theory
Journal of Vibration and Control, 2016Co-Authors: L B Qi, Y S Wu, Yong Duan, M X ShenAbstract:The three-dimensional sono-elasticity method recently developed by Zou ((2014) Three-dimensional sono-elasticity of ships. PhD Dissertation, China Ship Scientific Research Center, China) and Wu ((1984) Hydroelasticity of floating bodies. PhD Dissertation, Brunel University, UK) is employed to explore the acoustic and vibrational characteristics of a Propeller–Shaft–hull coupled system. The acoustic field can be solved by introducing Green’s function for the ideal compressible fluid together with the Price–Wu generalized fluid–structure interface boundary conditions. The vibration of a ship structure is governed by the generalized equations, including added mass, damping and restoring coefficients. In order to discover the mechanisms underlying the acoustic and vibrational characteristics of the Propeller–Shaft–hull coupled system, numerical models for hull structures with a Shaft and without a Shaft are designated. Through modal analysis, the correlations of the line spectra of acoustic radiation and the ...
