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  • 1.
    Chattopadhyay, G.
    et al.
    Queensland University of Technology.
    Kumar, Saurabh
    Larsson-Kråik, Per-Olof
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Estimation of parameter for rail degradation2006In: Condition Monitoring and Diagnostic Engineering Management: COMADEM 2006 ; proceedings of the 19th international congress, Luleºa, Sweden, 12 - 15 June 2006 / [ed] Uday Kumar, Luleå: Luleå tekniska universitet, 2006, p. 605-612Conference paper (Refereed)
    Abstract [en]

    Rail degradation is a significant problem for rail industries. Wear and fatigue comprises major component of rail degradation. It depends on operational conditions such as train speed, axle load, rail-wheel material type, size and profile, track construction, characteristics of bogie type, Million Gross Tonnes (MGT), curvature, traffic type, weather and environmental conditions. Development of prediction model related to those defects leading to rail breaks and/or rail replacements is vital for economic and safe operation of rail services. Estimation of parameter for failure models is necessary for accurate prediction of expected number of rail defects over a period of time based on Million Gross Tonnes (MGT) traffic, operating conditions and maintenance strategies. This paper focuses on collection and analysis of field data for various defects developed in rail track over a period of time for estimation of parameter for models predicting degradation of rails.

  • 2.
    Chattopadhyay, Gopi
    et al.
    Central Queensland University.
    Kumar, Saurabh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Parameter estimation for rail degradation model2009In: International Journal of Pedagogy, Innovation and New Technologies, ISSN 0973-1318, E-ISSN 2392-0092, Vol. 5, no 2, p. 119-130Article in journal (Refereed)
    Abstract [en]

    Wear and fatigue in rails are major contributors of rail degradation depending on operational conditions, track, characteristics of bogie type, Million Gross Tonnes (MGT), curvature, traffic type and environmental conditions. Estimation of parameter for failure models is necessary for accurate prediction of expected number of rail defects over a period of time based on MGT of traffic and operating conditions for developing cost effective maintenance strategies. This paper focuses on collection and analysis of field data over a period of time for estimation of parameter for modelling rail life.

  • 3.
    Kumar, Saurabh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A study of the rail degradation process to predict rail breaks2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Rail infrastructure is a large and costly investment, and has a long life. To realize the benefits from this investment, effective maintenance is required. Railways are one of the prime modes of transportation in many countries and as they are closely associated with passenger and cargo transportation, they own high risk in terms of potential loss of human life and damage/destruction of assets. New technologies and stringent safety standards are constantly being introduced, but accidents still occur. There will always be some risk associated with derailments and collisions, but it can be reduced by elimination of the root causes by means of an effective maintenance strategy to govern optimization of inspection, lubrication and grinding frequency and/or improvement in skill and efficiency. A detailed study of the defects which emerge both in the rolling stock and the rail infrastructure is essential to identify the correct maintenance strategy. Detection and rectification of rail defects/degradations are major issues for all rail players around the world. Some of the rail degradations include worn out rails, weld problems, internal defects, corrugations and rolling contact fatigue (RCF) initiated problems such as surface cracks, head checks, squats, spalling and shelling. If undetected and/or untreated, these defects can lead to rail breaks and derailments. Efficient maintenance strategies can reduce potential risk of rail breaks and derailments. A potential risk is the risk which accumulates in the form of rail degradation over a period of time. In spite of continuous efforts made by all rail infrastructure operators around the world to reduce costs, a substantial proportion of railway budget is spent on rail maintenance. It is understood that the consequential costs due to derailment reduces with increase in inspection, lubrication, grinding and replacement costs. The challenge is to find a balance between the maintenance costs which consists of inspection, lubrication and grinding costs, and consequential costs due to derailments. The consequences of derailment in terms of loss of human life, damage/destruction of assets and loss of company trust and reputation justify maintaining stringent safety standards, which require massive rail maintenance investments in order to be met. Reduction in maintenance investments may increase the rate of rail degradation, which may increase the risk of derailments. The aim is to develop an approach to predict rail failures, which will help to optimize maintenance activities (inspection, grinding, rectification/replacement and/or welding). Generally, there is a trade-off between maintenance investment and the risk involved in rail degradation in order to develop a rail maintenance procedure. Failure prediction of rail sections undergoing degradation will help to estimate the risk of derailment. Thus, prediction of the rail failure rate is a requirement for the development of an effective rail maintenance procedure. Different types of rail degradation processes leading to various rail defects have been studied. The performed literature studies indicate a need for better prediction of rail failure over a period of time based on the factors influencing rail degradation. The maintenance strategy followed by the Swedish National Rail Administration (Banverket), Sweden's rail infrastructure operator, is described and the issues related to rail degradation and maintenance are outlined for further research in this area. Rail failure data has been extracted from different Banverket's databases, classified according to a classification framework developed and analyzed over a period of time based on Million Gross Tonnes (MGT) of traffic using Weibull distribution. During the process of data evaluation and analysis, a method of extracting useful information from incomplete data has been identified.

  • 4.
    Kumar, Saurabh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Reliability analysis and cost modeling of degrading systems2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Degradation is an on-going process in systems, equipments and components subjected to various stresses and adverse operating conditions. The factors influencing the degradation process may adversely affect the system or component performance. A study of these factors will provide a basis for making correct decisions concerning corrective and preventive measures. Such a study is also useful for reliability analysis of the degrading systems/components for making maintenance decisions or for initiating measures for changes in the design. Many times it is not possible to implement design changes due to complexities and cost considerations, as in the case of railway infrastructures, etc. In such situations operational reliability is assured through effective maintenance actions. Knowledge of the technical condition of components is important to achieve the optimal maintenance policy in order to minimize the total system risk. A methodology for rail defect prioritization and risk assessment is developed to support the decision- making process during the effective scheduling of the inspection frequency based on the type of defect and its risk of developing into a rail break. The present research work also demonstrates an application of reliability analysis to improve system reliability based on design changes. This has been illustrated with an example from a manufacturing industry. The objective is achieved using cost-benefit analysis in combination with failure data and root cause analysis. The analysis of failure data with the different cost elements involved in the operation and maintenance of the complex systems is presented as a basis for choosing between alternative designs. Furthermore, an optimization model has been developed to estimate the optimum inspection frequency required at the minimum maintenance cost based on the technical condition of the component. The model has been validated by a case study of an offshore oil and gas platform. The consequences of not choosing the right distribution have also been discussed in the thesis. The concept of the virtual failure state has been introduced to estimate the failure distribution of highly critical components. The factors influencing the degradation process have been identified and studied in detail. A framework for classification of rail failure data has also been developed for rail life estimation using reliability analysis. In short, the thesis discusses the application of reliability analysis and cost modeling techniques to support the decision-making process in operation and maintenance activities and demonstrates its usefulness in real life.

  • 5.
    Kumar, Saurabh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Study of rail breaks: associated risks and maintenance strategies2006Report (Other academic)
    Abstract [en]

    Railways are large infrastructures and are the prime mode of transportation in many countries. As it is closely associated with passenger and cargo transportation, it owns high risk in terms of human lives and cost of assets. New technologies and better safety standards are constantly introduced but still accidents do occur. There will always be some risk associated with derailments and collisions but it can be reduced by elimination of the root causes. These causes necessitate an effective maintenance strategy to govern optimization of inspection frequency and/or improvement in skill and efficiency. A detailed study of the defects which emerge both on the rolling stock and rail infrastructure is essential to frame out the correct maintenance strategy. Detection and rectification of rail defects are major issues for all rail players around the world. Some of the defects include worn out rails, weld problems, internal defects, corrugations and rolling contact fatigue (RCF) initiated problems such as surface cracks, head checks, squats, spalling and shelling. If undetected and/or untreated these defects can lead to rail breaks and derailments. There are challenges to the infrastructure maintenance people to perform effective inspection and cost effective rectification decisions. If these issues are addressed properly, inspection and rectification decisions can reduce potential risk of rail breaks and derailments. In-spite of continuous efforts made by all rail operators around the world to reduce costs, a substantial amount of railway budget is spent on inspection and maintenance of rails. It is understood that the consequential cost due to derailment reduces with increase in inspection, lubrication and grinding costs. The challenge is to reduce the maintenance cost which consists of inspection, lubrication and grinding costs and at the same time prevent a rise in consequential cost due to derailment. Risk evaluation has become an important parameter for the management to decide a better and cost effective solution that could meet the budgetary constraints regarding renewal, replacement and inspection frequency of rails and wheels. Thus, before development of any model or any empirical relationship associated with risk, familiarity with risk management tools is required. This study focuses on building up a basic knowledge required for establishing such a relationship. The aim is to reduce costs and risks related to rail operation by effective decisions related to rail inspection, grinding, lubrications, rectifications and rail replacements. Different types of rail defects and degradation processes have been studied. From the literature survey and studies done by the author, it is interpreted that there is a need for better prediction of rail defects over a period of time based on operating conditions and maintenance strategies. The issues and challenges related to rail maintenance are outlined for further research in this area. The maintenance strategy followed by Banverket is also described.

  • 6. Kumar, Saurabh
    et al.
    Chattopadhyay, G.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, K.
    Application of design changes for improvement of system reliability: a case study2005In: Proceedings of 18th International Congress on Condition Monitoring and Diagnostic Engineering Management: Comadem - 2005, Cranfield: Cranfield University Press , 2005, p. 83-92Conference paper (Refereed)
  • 7. Kumar, Saurabh
    et al.
    Chattopadhyay, Gopi
    Queensland University of Technology School of Engineering Systems.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Reliability improvement through alternative designs: a case study2007In: Reliability Engineering & System Safety, ISSN 0951-8320, E-ISSN 1879-0836, Vol. 92, no 7, p. 983-991Article in journal (Refereed)
    Abstract [en]

    In today's competitive world, reliability of equipment is extremely important to maintain quality and delivery deadlines. This is achieved by using proper maintenance and design changes for unreliable subsystems and components of a complex system. It is significant to develop a strategy for maintenance, replacement and design changes related to those subsystems and components. An analysis of down time along with causes is essential to identify the unreliable components and subsystems. This paper presents an analysis of failure data of solenoid coils of automatic internal grinding machine used in a bearing manufacturing plant. It analyses various replacement and change of design options such as introduction of pneumatic system in place of electromagnetic solenoids for improvement of reliability of the plunger movement mechanism.

  • 8. Kumar, Saurabh
    et al.
    Dandotiya, Rajiv
    Kumar, Rajesh
    Aker Kvaerner, Stavanger.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Inspection frequency optimization model for degrading flowlines on an offshore platform2008In: International Journal of Reliability, Quality and Safety Engineering (IJRQSE), ISSN 0218-5393, Vol. 15, no 2, p. 167-180Article in journal (Refereed)
    Abstract [en]

    Many offshore oil and gas installations in the North Sea are approaching the end of their designed lifetimes. Technological improvements and higher oil prices have developed favorable conditions for more oil recovery from these existing installations. However, in most cases, an extended oil production period does not justify investment in new installations. Therefore cost-effective maintenance of the existing platform infrastructure is becoming very important. In this paper, an inspection frequency optimization model has been developed which can be used effectively by the inspection and maintenance personnel in the industry to estimate the number of inspections/optimum preventive maintenance time required for a degrading component at any age or interval in its lifecycle at a minimum total maintenance cost. The model can help in planning inspections and maintenance intervals for different components of the platform infrastructure. The model has been validated by a case study performed on flowlines installed on the top side of an offshore oil and gas platform in the North Sea. Reliability analysis has been carried out to arrive at the best inspection frequency for the flowline segments under study

  • 9. Kumar, Saurabh
    et al.
    Espling, Ulla
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A holistic procedure for rail maintenance in Sweden2008In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 222, no 4, p. 331-344Article in journal (Refereed)
    Abstract [en]

    The paper discusses a procedure for systematic and holistic (considering most of the factors influencing the rail degradation process) analysis and prediction of rail failures so that rail maintenance can be performed effectively. The current rail maintenance and reporting procedure followed by Banverket (Swedish National Rail Administration) for the Swedish Iron Ore Line is also described. The paper will also discuss on the improvement areas in Banverket's database management system highlighting what to measure and record and the reason behind it.This paper will help the infrastructure managers to better understand the existing rail maintenance procedure, and the improvements which can be incorporated in the existing procedure to make it more effective.

  • 10. Kumar, Saurabh
    et al.
    Gupta, Suprakash
    Ghodrati, Behzad
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    An approach for risk assessment of rail defects2010In: International Journal of Reliability, Quality and Safety Engineering (IJRQSE), ISSN 0218-5393, Vol. 17, no 4, p. 291-311Article in journal (Refereed)
    Abstract [en]

    Rail defects appear in a greater variety and frequency due to higher axle loads and increasing traffic density in passenger and freight trains. Many of these rail defects, if left undetected, can develop into rail breaks, which may lead to train derailments. Reduction in the number of such catastrophic events requires huge investments on inspection and maintenance activities. Therefore proper maintenance planning and risk assessment is required to reduce the rail maintenance cost without compromising safety. In this paper, an approach has been developed for risk assessment of rail defects to support the decision-making process during scheduling of rail inspection and grinding frequency, based on the type of defect and its risk of occurring and developing into a rail break. The approach will help in increasing the safety of passengers and rolling stock as well as reducing the overall rail maintenance cost, as it helps in making effective decisions related to inspection frequency (i.e. resource allocation according to the need). The approach is presented with the aid of a case study from the Swedish National Rail Administration (Banverket). Both, quantitative and qualitative analysis technique has been used in this paper to assess the risk of occurrence of a rail defect and its development into a rail break.

  • 11. Kumar, Saurabh
    et al.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Chattopadhyay, G.
    Queensland University.
    Reddy, V.
    Queensland University.
    Issues and challenges with logistics of rail maintenance2006In: Proceedings of Abstracts and Papers of The Second International Intelligent Logistics Systems Conference 2006 / [ed] Erhan Kozan, Australian Society for Operations Research , 2006, p. 16.1-16.9Conference paper (Refereed)
  • 12. Kumar, Saurabh
    et al.
    Mishra, N.M.
    Department of Applied Chemistry, Indian School of Mines, Dhanbad.
    Mukherjee, P.S.
    Department of Mechanical Engineering and Mining Machinery Engineering, Indian School of Mines, Dhanbad, Jharkhand.
    Additives depletion and engine oil condition: a case study2005In: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 57, no 2, p. 69-72Article in journal (Refereed)
  • 13. Kumar, Saurabh
    et al.
    Mukherjee, M.S.
    Department of Mechanical Engineering and Mining Machinery Engineering, Indian School of Mines, Dhanbad, Jharkhand.
    Mishra, N.M.
    Department of Applied Chemistry, Indian School of Mines, Dhanbad.
    Online condition monitoring of engine oil2005In: Industrial Lubrication and Tribology, ISSN 0036-8792, E-ISSN 1758-5775, Vol. 57, no 6, p. 260-267Article in journal (Refereed)
    Abstract [en]

    Purpose – Engine oil degrades in quality during its use and after certain period of time the oil needs to be changed depending upon its condition. The purpose of this paper is to design and develop an online condition monitoring device for engine oil. Design/methodology/approach – Based on the previous works in this line and some testing of used oils in the laboratory, the correlation of change in colour with other properties were identified. An optical colour sensor was then designed and developed which can transform the darkness of oil colour into electrical resistance. A series of tests were undertaken to calibrate the system for its correctness. Findings – This type of sensor provides the information about the condition of the oil and also can inform about the probable time for drain-off of the oil. Practical implications – Engine oil changes are normally done by schedules which are highly conservative and cost the user as the oil is changed when it could be still used for some time. Use of an online sensor will minimize the cost on lubricants to some extent. Originality/value – The device is of great value to the users of IC engines as it not only reduces the cost on lubricants but also informs the user about the present condition of the oil.

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