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  • 1.
    Ahmadi, Alireza
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Franson, Torbjörn
    Saab Aerosystems, Linköping.
    Crona, Anneli
    Saab Aerosystems, Linköping.
    Klein, Markus
    Saab Aerosystems, Linköping.
    Söderholm, Peter
    Integration of RCM and PHM for the next generation of aircraft2009In: 2009 IEEE Aerospace Conference: Big Sky, Montana, USA, 7 - 14 March 2009, Piscataway, NJ: IEEE Communications Society, 2009Conference paper (Refereed)
    Abstract [en]

    With global cuts in defense budgets, air forces have to sustain the same level of readiness with a reduced number of aircraft. To succeed with this challenge, it is not sufficient to improve current maintenance concepts, but new ones also have to be introduced.Traditionally, the development of on-board functions and maintenance concepts has been performed rather independently. The new approach is to focus on an integration of these two developments and to adapt a life cycle view together with a disregard of organizational boundaries.To facilitate the necessary change, a study is performed by Saab and Luleå University of Technology. The study focuses on the possibilities to integrate RCM and PHM in a cost-effective way. The aim is to reduce the workload of maintenance development and to find out how to combine RCM and PHM to achieve a joint development of the aircraft and its maintenance program throughout the aircraft's whole life cycle.The paper describes some similarities and differences between RCM and PHM. Furthermore, the paper describes some aspects of how RCM and PHM are complementing each other and what kind of adaptations that has to be done to achieve a successful integration. For example, a good application of RCM early in system design might generate a pull for PHM-technology integration and motivate design changes of the aircraft. Simultaneously, available PHM-technologies might strongly affect the selection of applicable and effective maintenance tasks in the development of the initial maintenance program. PHM might also support a surveillance of the maintenance program's performance. The description is highlighted with examples and experiences from the Swedish Gripen fighter aircraft. Finally, the paper also outlines some suggestions for further research.

  • 2.
    Ahmadi, Alireza
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    On aircraft scheduled maintenance program development2010In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 16, no 3, 229-255 p.Article in journal (Refereed)
    Abstract [en]

    Purpose – The purpose of this paper is to present issues and challenges of scheduled maintenance task development within the maintenance review board (MRB) process, and to find potential areas of improvement in the application of the MSG-3 methodology for aircraft systems. Design/methodology/approach – The issues and challenges as well as potential areas of improvement have been identified through a constructive review that consists of two parts. The first part is a benchmarking between the Maintenance Steering Group (MSG-3) methodology and other established and documented versions of reliability-centred maintenance (RCM). This benchmarking focuses on the MSG-3 methodology and compares it with some RCM standards to identify differences and thereby find ways to facilitate the application of MSG-3. The second part includes a discussion about methodologies and tools that can support different steps of the MSG-3 methodology within the framework of the MRB process. Findings – The MSG-3 methodology is closely related to the RCM methodology, in which the anticipated consequences of failure are considered for risk evaluation. However, MSG-3 considers neither environmental effects of failures nor operational consequences of hidden failures. Furthermore, in MSG-3, the operational check (failure-finding inspection) is given priority before all other tasks, whereas in RCM it is considered as a default action, where there is no other applicable and effective option. While RCM allows cost-effectiveness analysis for all failures that have no safety consequences, MSG-3 just allows it for failures with economic consequences. A maintenance program that is established through the MRB process fulfils the requirements of continuous airworthiness, but there is no foundation to claim that it is the optimal or the most effective program from an operator’s point-of-view. The major challenge when striving to achieve a more effective maintenance program within the MRB process is to acquire supporting methodologies and tools for adequate risk analysis, for optimal interval assignments, and for selection of the most effective maintenance task. Originality/value – The paper presents a critical review of existing aircraft scheduled maintenance program development methodologies, and demonstrates the differences between MSG-3 and other RCM methodologies.

  • 3. Ahmadi, Alireza
    et al.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Risk of operational consequences of aircraft system failure2010In: International Journal of Pedagogy, Innovation and New Technologies, ISSN 0973-1318, E-ISSN 2392-0092, Vol. 6, no 2, 149-158 p.Article in journal (Refereed)
    Abstract [en]

    The purpose of this paper is to describe a methodology for identifying different operational consequences and associated costs caused by aircraft system failure, in order to facilitate and enhance the capability of taking correct and efficient decisions when analyzing the cost-effectiveness of maintenance tasks. The paper focuses on the operational consequences of failures that lead to delay. To identify the operational consequences of aircraft system failures, Empirical studies of possible scenarios involving aircraft failures and their operational consequences for a commercial airline have been performed. Empirical data were extracted through document studies and interviews, guided by the application of an Event Tree Analysis (ETA). In order to effectively utilize the knowledge of field experts in the assessment process, a pairwise comparison technique was adopted for quantifying the contribution of different factors to the operational. The work was performed together with experienced practitioners from both an aircraft manufacturer and commercial airlines, which contributed to a continuous verification of the outcome of the study.The study shows that the proposed methodology based on ETA and pairwise comparison can be used to identify and quantify the cost of operational consequences of failures in aircraft operation, when there is no sufficient and reliable data.

  • 4. Ahmadi, Alireza
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Assessment of the operational consequences of aircraft failures: using event tree analysis2008In: 2008 IEEE Aerospace Conference: 1-8 March 2008 : [Big Sky, Montana]., Piscataway, NJ: IEEE Communications Society, 2008, 1-14 p.Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is to describe a methodology that supports an assessment of the operational consequences of failures in aircraft systems and its associated costs, in order to facilitate a correct and efficient decision-making during cost-effectiveness analysis of maintenance tasks within scheduled aircraft maintenance program development. The paper is based on empirical studies of possible scenarios from aircraft failure to operational consequences in commercial airlines. Empirical data was extracted through document studies and interviews, guided by the application of an Event Tree Analysis (ETA). The analysis was performed together with experienced practitioners from both an aircraft manufacturer and commercial airlines, which contributed to a continuous verification of the outcomes of the study. The proposed methodology, which is based on ETA, is considered as a valuable support in the assessment of the operational consequences of failures within a MSG-3 framework. The proposed methodology focuses on assessing the operational consequences of failures and associated economical losses. Hence, in order to enable an estimation of the maintenance tasks' cost-effectiveness, the methodology should be further developed to include a cost assessment of the applicable maintenance tasks. The proposed methodology could be adapted as a support to those involved in the development of aircraft maintenance program. The operational consequences and the probabilities of the proposed event tree can be quantified by the aid of historical data or expert judgment.

  • 5.
    Ahmadi, Alireza
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Kumar, Uday
    An overview of trends in aircraft maintenance program development: past, present, and future2007In: Risk, Reliability and Societal Safety: Pproceedings of the European Safety and Reliability Conference 2007 (ESREL 2007), Stavanger, Norway, 25 - 27 June 2007 / [ed] Terje Aven; Jan Erik Vinnem, London: Taylor and Francis Group , 2007, 2067-2076 p.Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is to describe the trends in aircraft maintenance program development during the last 50 years, including the reasons for the aircraft industry to change its view of maintenance. The major milestones and fundamental reasons for such development are also discussed and illustrated in relation to a flow diagram, which shows the logical and chronological order of the trends. Finally, the paper describes some possibilities and challenges as regards applying Information & Communication Technology (ICT) within the emerging approach of e-Maintenance in order to enhance the surveillance of aircraft maintenance program performance.

  • 6.
    Backlund, Fredrik
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Holmberg, Rikard
    Vattenfall Vattenkraft.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A 10 years journey introducing RCM within hydropower: a case study at Vattenfall Vattenkraft2008In: EuroMaintenance Papers: Conference and Trade Show on Asset Management & Production Reliability ; Brussels Expo, 8 - 10 April 2008, Belgian Maintenance Association , 2008, 21:1-21:10 p.Conference paper (Refereed)
  • 7.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Trafikverket.
    Control charts for assessment of linear asset condition using both temporal and spatial information2012In: Proceedings of the 2nd International Workshop & Congress on eMaintenance: Dec 12-14 Luleå, Sweden : eMaintenace: trends in technologies and methodologies, challenges, possibilities and applications / [ed] Ramin Karim; Aditya Parida; Uday Kumar, Luleå: Luleå tekniska universitet, 2012, 145-152 p.Conference paper (Refereed)
  • 8.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Trafikverket.
    Control Charts supporting Condition-Based Maintenance of Linear Railway Infrastructure Assets2014In: Proceedings of the 3rd international workshop and congress on eMaintenance: June 17-18 Luleå, Sweden : eMaintenance, Trends in technologies & methodologies, challenges, possibilites and applications / [ed] Uday Kumar; Ramin Karim; Aditya Parida; Philip Tretten, Luleå: Luleå tekniska universitet, 2014, 101-107 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a control chart approach for monitoring,diagnostics and prognostics to support condition-basedmaintenance (CBM) using condition data of linear railwayinfrastructure assets. The condition data were obtained fromregular inspections done by a railway track measurement wagon.The condition data were statistically analysed by using twodifferent control charts to evaluate the possibility for earlierdetection of derailment hazardous faults using both temporal andspatial information. The study indicates that that the proposedcontrol chart approach can be used for condition assessment oftrack and thereby provide valuable decision support for CBM. Thecontrol chart for condition information in the temporal domainsupports diagnostics, while the control chart for conditioninformation in the spatiotemporal domain also supportsprognostics. The two proposed control charts give earlier faultwarnings compared to the traditional approach. This facilitatesdecisions regarding CBM actions with an extended planninghorizon and gives the possibility to increase the operationalavailability of track.

  • 9.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Control Charts supporting Condition-Based Maintenance of Linear Railway Infrastructure Assets2015In: International Journal of COMADEM, ISSN 1363-7681, Vol. 18, no 2, 7-16 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a control chart approach for monitoring, diagnostics and prognostics to support condition-based maintenance (CBM) using condition data of linear railway infrastructure assets. The condition data were obtained from regular inspections done by a railway track measurement wagon. The condition data were statistically analysed by using two different control charts to evaluate the possibility for earlier detection of derailment hazardous faults using both temporal and spatial information.The study indicates that that the proposed control chart approach can be used for condition assessment of track and thereby provides valuable decision support for CBM. The control chart for condition information in the temporal domain supports diagnostics, while the control chart for condition information in the spatiotemporal domain also supports prognostics. The two proposed control charts give earlier fault warnings compared to the traditional approach. This facilitates decisions regarding CBM actions with an extended planning horizon and gives the possibility to increase the operational availability of track.

  • 10.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Data Analysis for Condition-Based Railway Infrastructure Maintenance2015In: Quality and Reliability Engineering International, ISSN 0748-8017, E-ISSN 1099-1638, Vol. 31, no 5, 773-781 p.Article in journal (Refereed)
    Abstract [en]

    Condition assessment is crucial to optimize condition-based maintenance actions of assets such as railway infrastructure, where a faulty state might have severe consequences. Hence, railways are regularly inspected to detect failure events and prevent the inspected item (e.g. rail) to reach a faulty state with potentially safety critical consequences (e.g. derailment). However, the preventive measures (e.g. condition-based maintenance) initiated by the inspection results may cause traffic disturbances, especially if the expected time to a faulty state is short. The alarm limits are traditionally safety related and often based on geometrical properties of the inspected item. Maintenance limits would reduce the level of emergency, producing earlier alarms and increasing possibilities of planned preventive rather than acute maintenance. However, selecting these earlier maintenance limits in a systematic way while balancing the risk of undetected safety-critical faults and false alarms is challenging. Here, we propose a statistically based approach using condition data of linear railway infrastructure assets. The data were obtained from regular inspections done by a railway track measurement wagon. The condition data were analysed by a control chart approach to evaluate the possibility for earlier detection of derailment hazardous faults using both temporal and spatial information. The study indicates that that the proposed approach could be used for condition assessment of tracks. Control charts led to earlier fault warnings compared to the traditional approach, facilitating planned condition-based maintenance actions and thereby a reduction of track downtime

  • 11.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Improved Condition Assessment through Statistical Analyses: Case Study of Railway Track2017Report (Other academic)
    Abstract [en]

    Traditional practice within railway maintenance is based on engineering knowledge and practical experience, which are documented in regulations. This practice is often time-based, but can also be condition-based by combining time-based inspections with condition-based actions depending on the inspection results. However, the logic behind the resulting regulation is seldom well documented, which makes it challenging to optimise maintenance based on factors such as operational conditions or new technologies, methodologies and best practices. One way to deal with this challenge is to use statistical analysis and build models that support fault diagnostics and failure prognostics. This analysis approach will increase in importance as automated inspections replace manual inspections. Specific measurement equipment and trains are not the only ones producing automated measurements; regular traffic is increasingly often producing measurements. Hence, there will not be any lack of condition data, but the challenge will be to use this data in a correct way and to extract reliable information as decision support. In this context, it is crucial to balance the risks of false alarms and unrecognised faults, but also to estimate the quality of both data and information. The purpose of this work is to use statistics in order to support improved asset management, by building statistical models as a complement to physical models and engineering knowledge. The resulting models combine theories from the field of time-series analysis, statistical process control (SPC) and measurement system analysis. Charts and plots present results and have prognostic capabilities that allow necessary track possession times to be included in the timetable. 

  • 12.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Measurement System Analysis of Railway Track Geometry Data using Secondary Data2016Conference paper (Refereed)
    Abstract [en]

    In this paper, we use secondary data to make a partial measurement system analysis of railway measurement cars and their obtained track geometry data. When a measurement car passes the same track section shortly after the previous passage, such as returning in the other direction after reaching a railway endpoint, the repeated measurements hold information of the measurement uncertainty of that car. Reasons for the measurement uncertainty can be sought in other variables that also are stored in the database, such as the individual car identity, the type of car, the speed of the car during measurement, and the travelled direction of the car. By also considering other known factors during the time of measurement as regressors, such as ground frost periods, enhanced modelling may be achieved and also indicate if such periods should be avoided to improve the measurement data quality.The results of this study suggest that the type of car had the largest influence on measurement variation out of the studied regressors. If the variation of a track geometry property on a track section is studied, the variation component belonging to the type of car can be deducted, improving data quality. We suggest that the method could also be used to find track sections that are prone to large seasonal variation, such as due to ground frost.

  • 13.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Measurement Systems Analysis of Railway Measurement Cars2016Conference paper (Refereed)
    Abstract [en]

    Purpose: The presentation proposes ways to understand and quantify the variation component due to the measurement system of railway track properties using subsequent runs from measurement cars.Background: Railway infrastructure conditions are commonly inspected by using measurement cars. The measurements are performed with some regularity, and the inspection frequencies could for instance be set taking into account the common train axle loads, railway speed or load bearing classification, number of trains passing, the known railway condition, or the availability of the measurement cars. By combining different inspections of the same track section, it is also possible to monitor the degradation of the infrastructure over time. Often, the railway system is inspected by many measurement cars, and for single tracks, measurements can be obtained from the car travelling in different directions. The measurements are performed at different speeds, related to random variation, but also to the maximum speeds at which the measurement cars operate. The measurements are also afflicted by external variation sources, some of which are acting with a known direction, such as the wear of the track which increases property variation. Maintenance usually (but not always) result in reduced property variation, whereas other sources such as climate related properties such as spring thaw may induce variation over time, but also induce variation that show a periodic behavior with periods with increasing as well as decreasing property variation. This presentation aims to devise a model for how these variation sources may be separated, with the main aim to classify measurement error, but also to estimate the magnitude of other variation sources.Method: No statistically significant differences were found between repeated measurements of cars travelling back and forth on the single track found at the Swedish Iron ore line. These measurements contain measurement error as well as error due to short term degradation and variation due to measurement. As measurement variance is added, it was concluded that the measurement variation could not be larger than the variation shown by repeat measurements. By comparing repeated measurements over time and subtracting variation due to wear, measurement variation for different cars, measurement speeds and measurement directions was estimated using Generalized Linear Models regression analysis. Co-variation between measurement cars and measurement speeds were accounted for using Ridge regression and Elastic Net regression.Results: The regression analysis shows that whereas both measurement speed and the measurement car individuals correlate with the measurement variation obtained, regularized regression points to the measurement cars as the major variation factor and that different measurement cars have different measurement precisionDiscussion and conclusion: The study demonstrates how repeated measurements from regular process data and thus not obtained using the regular and systematic experimental procedures of measurement system analysis can be used for estimation of the variation components of the measurement system. As a side effect, the sizes of other variation sources, external to the measurement system, can be estimated.

  • 14.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Predictive Modelling for Estimation of Railway Track Degradation2016In: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadu; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, 331-347 p.Conference paper (Refereed)
    Abstract [en]

    The degradation processes affecting railway track condition depends both on the resistance of the track and on the stresses subjected to it. Regarding the stresses, both their magnitudes and cycles are of importance when considering the degradation. Furthermore, the stresses have some regularity and variability in the time domain, while the degradation resistance of a track has some spatial regularity as well as variability. In addition, the condition measurements of track may be both irregular and contain measurement errors. Hence, it is challenging to model the condition of track to enable predictions and condition-based maintenance. However, wear prediction models could help to change large parts of the maintenance practice from predominantly corrective to preventive if both the deterministic and the stochastic components of the wear process can be estimated with sufficient accuracy. In this study, one-step-ahead predictions have been used for establishing prognostic models based on repeated measurements of railway track geometry to estimate track wear properties, degradation rates and stochastic behaviour including measurement errors. The prognostic models have then been used for condition assessment and state predictions. Repeated sampling allows for estimations of measurement errors, but the irregular sampling need to be accounted for by interpolation in the time series modelling approach

  • 15.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Projekt: Förbättrad tillståndsbedömning genom statistisk analys2015Other (Other (popular science, discussion, etc.))
  • 16.
    Bergquist, Bjarne
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Eriksson, Per-Erik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Karrbom Gustavsson, Tina
    Arkitektur och samhällsbyggnad, KTH, Sverige.
    Projekt: Offentlig upphandling av järnvägsunderhåll2015Other (Other (popular science, discussion, etc.))
  • 17.
    Block, J.
    et al.
    Saab Aerotech, Linköping.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Tyrberg, T.
    Saab Aerotech, Linköping.
    Evaluation of preventive maintenance task intervals using field data from a complete life cycle2008In: IEEE Aerospace Conference Proceedings: -8 March 2008 : [Big Sky, Montana]., Piscataway, N.J: IEEE Communications Society, 2008, Vol. Article number 4526635, 1-11 p.Conference paper (Refereed)
    Abstract [en]

    In this paper the appropriateness of initial preventive maintenance task intervals and the improvement of changed intervals are evaluated. The evaluation criteria are partly derived from logic found in the RCM (Reliability-Centered Maintenance) methodology. Empirical data is related to the whole life cycle of the Swedish military aircraft system FPL 37 Viggen, from 1977 to 2006. The analysis shows that the maintenance intervals are partly appropriate and that some performed changes are improvements. These conclusions are strengthened if the phase-out of the aircraft system is considered, where the preventive maintenance strategy has been replaced with a corrective one, in order to achieve cost-effectiveness. Considering the perfect repair assumption, it seems that the overhaul tasks essentially bring the items back to a state as good as new. The performed evaluation mostly considers when the failures are recognized, i.e. during operation or during maintenance. Hence, aspects such as item accessibility, personnel skill levels, and maintenance task intervals for other items are not included in the evaluation.

  • 18.
    Block, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ahmadi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Tyrberg, Tommy
    Logistics Analysis and Fleet Monitoring, Saab Support and Services, Linköping.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Part-out-based spares provisioning management: A military aviation maintenance case study2014In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 20, no 1, 76-95 p.Article in journal (Refereed)
    Abstract [en]

    Purpose – The purpose of this paper is to present the prerequisites for a part-out-based spares provisioning (PBSP) programme during the phase-out of an aircraft fleet. Furthermore, associated key decision criteria are identified and a framework for the phase-out management process is presented. Design/methodology/approach – Once a decision has been taken to phase-out an aircraft fleet, a number of routines for operations, maintenance and storage are affected and new tasks and functions must be introduced before initiating the actual parting-out process. A decision-making system and a management framework is needed to manage spares planning during the end-of-life phase to ensure availability at minimum cost and to ensure a manageable risk of backorders. Findings – For PBSP programme during the phase-out of an aircraft fleet to succeed and be cost-effective, a number of linked processes, tasks and decisions are required, e.g., those included in the framework proposed in this paper (see Figure 3). A successful implementation of PBSP also requires that these processes and tasks are carried out in a timely manner and that the communications between the concerned parties are prompt, clear and direct. One experience from the studied case is that close and trustful contacts and cooperation between the operator and maintenance provider(s) will greatly facilitate the process. Originality/value – Although the PBSP method is fairly commonly applied within both the military and the civilian sector, somewhat surprisingly very literature has been published on the subject. Indeed, remarkably little has been published on any aspects of maintenance during the end-of-life period.

  • 19. Block, Jan
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Tyrberg, Tommy
    Saab Aerotech.
    Changes in items' failure pattern during maintenance: an investigation of the perfect repair assumption2008In: Annual Reliability and Maintainability Symposium, 2008: RAMS 2008 ; Las Vegas, Nevada, USA, 2008, 28 - 31 Jan, Piscataway, NJ: IEEE Communications Society, 2008, 117-122 p.Conference paper (Refereed)
    Abstract [en]

    It is clear that the simple ‘perfect repair' assumption is not immediately applicable to any of the studied types of hardware, i.e. Cooling Turbine, High-Voltage Generator, Hydraulic Accumulator, and Radar Transmitter. Hence, the assumption of ‘perfect repair' needs to be validated for each specific type of item. Assumptions based on the type of physical hardware (e.g. mechanical item or avionics item) are not always trustworthy.Strangely enough the ‘perfect repair' assumption fits best for the Cooling Turbine, which is a highly stressed mechanical item, while the fit is much poorer for the Radar Transmitter, which is an avionics item and for the Hydraulic Accumulator.For the Radar Transmitter the trend seems to be very scattered. For items with a large number of failures early in their life-cycle, repair is ‘better than perfect', i.e. the items become more reliable after repair, presumably by elimination of less reliable subcomponents. However, this effect is not seen for items with few failures early in their life-cycle. For these items ‘perfect repair' initially seems to be a valid model. However, in many cases repair becomes ‘less than perfect' later in the life-cycle. For the Hydraulic Accumulator this trend is even more accentuated and individual items seem to fall into two distinct subpopulations with opposite reliability trends.

  • 20.
    Block, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Tyrberg, T.
    Saab Aerotech.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    No Fault Found events during the operational life of military aircraft items2009In: 8th International Conference on Reliability, Maintainability and Safety, 2009: ICRMS 2009 ; 20 - 24 July 2009, Chengdu, China / [ed] Rui Kang, Piscataway, NJ: IEEE Communications Society, 2009, 920-924 p.Conference paper (Refereed)
    Abstract [en]

    No fault found (NFF) events are critical and well-known problems for certain aircraft items. This paper presents a study of these events for repairable items with on-condition maintenance, based on operational data from a military aircraft. Some findings are that: the number of NFF events is influenced by item type and number of repairs; most NFF events are initiated by faults recognized during operation; and different inspections contribute to NFF events. Hence, item design and tests at different operational modes and maintenance echelons should be better aligned to reduce the number of NFF events

  • 21.
    Candell, Olov
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Karim, Ramin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    eMaintenance - information logistics for maintenance support2009In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 25, no 6, 937-944 p.Article in journal (Refereed)
    Abstract [en]

    Today‟s providers of maintenance and in-service support related to modern aircraft are facing major challenges. A central problem with Maintenance, Repair and Overhaul (MRO) as well as support of aircraft and other complex technical systems, is to manage the ever-increasing information flow and system complexity. Both military and commercial operators need to reduce aircraft downtime and maintenance man hours. Increased manual information management has the opposite effect, inducing unnecessary cost and affect efficiency negatively. Organisations developing and providing maintenance support products and in-service support does also need to improve the capability to efficiently exploit the increasing amount of digital product information and design data provided together with hardware (HW) and software (SW) products from aircraft manufacturers, sub-system suppliers and Original Equipment Manufacturers (OEM). One way to increase aircraft availability and improve maintenance and support efficiency, is to speed up the turnaround time for scheduled and unscheduled maintenance. The ultimate goal is risk-based utilisation and support, where true Condition-Based Maintenance (CBM) is integrated with current operational requirements and available resources in real-time. This aims at the elimination of all preventive scheduled maintenance based on fixed time intervals and execution of only corrective maintenance that has been predicted and turned into scheduled maintenance facilitated by proper support. To address the challenge of information logistics of digital product data and information within maintenance in-service support, providers need to adapt new methodologies and tools that enable full utilisation of the advantages of digital product data and information in processes and business models, e.g. Service-Oriented Architecture (SOA). In order to implement such improved support solutions in a global support environment, eMaintenance is seen as one important building block. eMaintenance includes monitoring, collection, recording and distribution of real-time system health data, maintenance generated data as well as other decision and performance support information to different stakeholders independent of organization or geographical location, 24 hours a day, 7 days a week (24/7). eMaintenance has the potential to improve the management and performance of activities related to the whole maintenance process, and thereby improve the dependability, safety and Life Cycle Cost (LCC) of critical systems. This can be realized through a coordinated application of Information & Communication Technology (ICT) throughout the maintenance and support processes, thus integrating Built-in Test (BIT) systems, external tests at different maintenance echelons, technical information, diagnostics, prognostics and other sources of support information. The purpose of this paper is to present some results from a joint academic and aerospace industry research project, describing requirements and expectations that are important in a global support environment, and also to propose some central components in an eMaintenance framework that integrates maintenance and ICT perspectives.

  • 22. Candell, Olov
    et al.
    Karim, Ramin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Kumar, Uday
    Server-oriented information logistics as support to intelligent transport services2010In: 16th World Congress and Exhibition on Intelligent Transport Systems 2009: 16th ITS World Congress ; Stockholm, Sweden, 21 - 25 September 2009, Curran Associates, Inc., 2010Conference paper (Refereed)
    Abstract [en]

    Today‟s society is dependent on an increasing volume of transportation services, which contributes to escalating requirements on economy, dependability, safety, and sustainability of applied transportation systems. When dealing with complex transportation systems with long life cycles, maintenance is fundamental to ensure these critical requirements. The increasing requirements and the technological development have also lead to the emerging approach of eMaintenance, which applies innovative Information & Communication Technology (ICT) to achieve effective information logistics for maintenance purposes. This paper describes the role and development of service-oriented eMaintenance solutions to enable intelligent transportation services and some related research efforts within railway and aviation.

  • 23.
    Candell, Olov
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A customer and product support perspective of e-maintenance2006In: Condition Monitoring and Diagnostic Engineering Management: COMADEM 2006 ; proceedings of the 19th international congress, Luleå, Sweden, 12 - 15 June 2006 / [ed] Uday Kumar, Luleå: Luleå tekniska universitet, 2006, 243-252 p.Conference paper (Refereed)
    Abstract [en]

    Today the providers of customer and product support related to military aircraft are facing major challenges. Traditionally, aircraft systems have stringent requirements on safety. In addition to this, the requirements on dependability, costs, and security have increased in importance. These changes, together with an increased diversity of customer requirements in a global utilization environment, add to the complexity of providing appropriate support solutions. The increased customer requirements have also lead to concepts such as total solution selling, or functional products, where the customers are offered availability performance to a fixed price. In order to enable efficient support solutions in a global support environment, e-Maintenance is seen as one important building block. e-Maintenance includes monitoring, collection, and distribution of realtime system health data and information to all stakeholders independent of organizational belonging or geographical location, 24 hours a day, 7 days a week (24-7). The concept of e-Maintenance is realized through the application of Information & Communication Technology (ICT), which integrates built-in tests, external tests at different maintenance echelons, and other sources of support information. The purpose of this paper is to describe important requirements and expectations that a provider of customer and product support related to military aircraft systems has on e-Maintenance in a global support environment.

  • 24. Granström, Rikard
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Condition monitoring of railway wheels and no fault found problems2009In: International Journal of COMADEM, ISSN 1363-7681, Vol. 12, no 2, 46-53 p.Article in journal (Refereed)
    Abstract [en]

    Defective railway wheels can cause severe damages to both track and vehicle items, which in worst case can lead to derailments with extensive losses. Wheel impact detection systems are intended to support prevention of railway damages and its related losses, through recognition of wheel defects and generation of alarms. While commissioning of a wheel impact detection system in Sweden, it was revealed that the detection system was reliable as they were not generating any false alarms. However, during operation some of the system's alarms resulted in No Fault Found (NFF) events. Hence an investigation was launched to determine if the cause of the NFF events were false alarms generated by the detection system, or the inability of subsequent manual inspection to replicate the detection system's test result. This paper presents experiences from the verification study and links these to international experiences illustrating how wheel impact detection systems can support continuous assessment of wheel condition and related condition based maintenance efforts.

  • 25. Granström, Rikard
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Punctuality measurements effect on the maintenance process: a study of train delay statistics for the Swedish railway2005In: Abstracts of the Eighth International Conference "Maintenance & Renewal of Permanent Way; Power & Signalling; Structures & Earthworks": Railway Engineering 2005 / [ed] M.C. Forde, Engineering Technics Press , 2005, 22- p.Conference paper (Other academic)
    Abstract [en]

    Governmental regulations state that the Swedish national railway administrator Banverket has an overall responsibility for train punctuality, independent of whether train delays are caused by Banverket or the train operating companies. Banverket is responsible for the functioning of the railway system as a whole, but can with own maintenance and reinvestment activities only affect the infrastructure. Conflicts derive from the two stakeholders' different roles and interests. In order to effectively forecast maintenance needs and costs of the infrastructure, Banverket want that the infrastructure's deterioration caused by the rolling stock should be both as small and as predictable as possible. However, the train operating companies look at the same situation from the other point of view, with a focus on their rolling stock. The interrelationship between the two stakeholder roles and their combined maintenance process is complex, since it is difficult to pinpoint the responsibility for the whole transport system and separate assets. One essential approach, in order to monitor low performance linked to responsible stakeholder roles and causes is to follow up the two measures punctuality and train delays. This paper explores the characteristics of existing train delay statistics and describes risks when maintenance efforts and design of incentives for improved railway operation is based on statistics that does not reflect the true root-causes of problems.

  • 26. Granström, Rikard
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Verification and utilization of wheel impact detection systems2006In: 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, 667-676 p.Conference paper (Refereed)
    Abstract [en]

    Defective rail wheels can cause severe damages to both track and vehicle components, which in worst case can lead to derailments with extensive losses. Wheel impact detection systems are intended to prevent railway damages and its related losses, through recognition of wheel defects and generation of alarms. At commissioning of a wheel impact detection system in Sweden, the commissioning study showed that the system was reliable, without generating any false alarms. However, during operation some of the system's alarms resulted in No Fault Found (NFF) events at subsequent manual inspections. Hence, a verification study was launched in order to determine if the cause of the NFF events were false alarms generated by the system, or the inability of subsequent manual inspection to replicate the system's test result. The verification study was expected to support an exclusion of the manual inspection, which was perceived to be the cause of the NFF events. However, an exclusion of the manual inspection would require the wheel impact detection system to be highly reliable, since it would be the primary foundation for decisions about both operation and maintenance. This study reports on vital experiences from the verification study and links these to experiences from other countries. The experiences highlight the importance of data accuracy and appropriate information management, in order to achieve the potential benefits and avoid the drawbacks of condition monitoring.

  • 27.
    Holmgren, Mattias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A process approach to maintenance-related hazard identification2008In: International Journal of COMADEM, ISSN 1363-7681, Vol. 11, no 1, 36-46 p.Article in journal (Refereed)
    Abstract [en]

    History has shown that maintenance contributes to incidents and accidents with extensive losses. The purpose of this paper is to describe a process approach for maintenance-related hazard identification, in order to support continuous risk reduction in maintenance activities. The proposed maintenance process model has been applied within a study of maintenance execution of DC-motors in paper-mills. However, both the model and the findings from its application are believed to be transferable to the maintenance of other critical technical systems. A recurring hazard is insufficient feedback. Hence, proper feedback may help to reduce risk. Further findings indicate that incidents manifested during execution may be due to hazards in other process phases. The maintenance of complex and critical systems is also affected by the work environment and knowledge of technicians, whose requirements should be fulfilled through appropriate organisational and technical support.

  • 28.
    Karim, Ramin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Candell, Olov
    Söderholm, Peter
    Development of ICT-based maintenance support services2009In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 15, no 2, 127-150 p.Article in journal (Refereed)
    Abstract [en]

    Purpose - The purpose of this paper is to describe a taxonomy for an eMaintenance management framework (eMMF) based on a service-oriented approach, in order to facilitate the development of information and communication technology (ICT)-based maintenance support services aimed at actors within the maintenance process related to complex technical industrial systems. Design/methodology/approach - To fulfil this purpose, a case study of a modern multi-role combat aircraft is selected as an appropriate research strategy and supported by a literature study. Empirical data are collected through interviews, workshops, document studies, and observations. A framework is developed and evaluated using a prototype within the studied case. The study is performed in close cooperation with the aircraft's type certificate holder and the customer representative and operator in one country. Findings - The proposed eMMF aids in the identification and development of ICT-based maintenance support services tailored for specific maintenance actors and their activities. Research limitations/implications - To further test the usefulness of the proposed framework, a larger scale application must be performed. This can involve additional stakeholders or a larger part of the technical system in the selected case, or another case dealing with complex technical industrial systems. Practical implications - The proposed framework supports the identification of required information services that support the maintenance process, which in turn supports the development of a service-oriented architecture (SOA) aimed at proper maintenance information logistics. Hence, people working with information logistics for maintenance purposes can use the framework as a support tool. Originality/value - The proposed framework combines a process and service-oriented approach, which facilitates the development of SOA-based information services by giving valuable input to more traditional system-oriented approaches

  • 29.
    Karim, Ramin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Candell, Olov
    Söderholm, Peter
    E-maintenance and information logistics: aspects of content format2009In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 15, no 3, 308-324 p.Article in journal (Refereed)
    Abstract [en]

    PurposeThe purpose of this paper is to describe aspects of content sharing within eMaintenance, with a view to merging the two areas of maintenance and ICT in a content management perspective. The purpose of this paper is to describe aspects of content sharing within eMaintenance, with a view to merging the two areas of maintenance and ICT in a content management perspective. Design/methodology/approachThe approach is an explorative literature study covering aspects of ICT. The analysis was founded on theories related to maintenance and maintenance support. The conclusions of the study are corroborated by experiences from earlier software development and testing. The approach is an explorative literature study covering aspects of ICT. The analysis was founded on theories related to maintenance and maintenance support. The conclusions of the study are corroborated by experiences from earlier software development and testing. FindingsMost existing contributions to the eMaintenance debate seem to suffer from too wide a gap between data processing and knowledge management. This tendency can be due to too great a focus on data collection, without any clear identification of the stakeholders‟ requirements. Hence, a mature eMaintenance solution should focus on the enhancement of service-oriented information logistics based on content sharing for an output-based information strategy. Most existing contributions to the eMaintenance debate seem to suffer from too wide a gap between data processing and knowledge management. This tendency can be due to too great a focus on data collection, without any clear identification of the stakeholders‟ requirements. Hence, a mature eMaintenance solution should focus on the enhancement of service-oriented information logistics based on content sharing for an output-based information strategy. Research limitations/implicationsThis study focuses on the needs of content format and transformation content, which includes data format, data structures and data type for objects that are relevant for the maintenance process. Hence, further research could include aspects of infrastructure and service architecture, which are on a higher level of an eMaintenance solution. This study focuses on the needs of content format and transformation content, which includes data format, data structures and data type for objects that are relevant for the maintenance process. Hence, further research could include aspects of infrastructure and service architecture, which are on a higher level of an eMaintenance solution. Practical implicationsThe paper contributes with knowledge that supports decisions about content format in the development of an eMaintenance solution. This can in turn support a reduction of maintenance-related hazards through improved use of ICT. The paper contributes with knowledge that supports decisions about content format in the development of an eMaintenance solution. This can in turn support a reduction of maintenance-related hazards through improved use of ICT. What is original/value of paperThis paper describes the importance of content management within the eMaintenance approach. Hence, the paper has implications for both practitioners and researchers as described above. This paper describes the importance of content management within the eMaintenance approach. Hence, the paper has implications for both practitioners and researchers as described above.

  • 30. Karim, Ramin
    et al.
    Kajko-Mattsson, Mira
    Department of Computer and Systems Sciences, Stockholm University, Royal Institute of Technology.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Exploiting SOA within emaintenance2008In: Proceedings of the 2nd international workshop on Systems development in SOA environments: International Conference on Software Engineering. Session: SOA supporting business process management (BPM), Piscataway, NJ: IEEE Communications Society, 2008, 75-80 p.Conference paper (Refereed)
    Abstract [en]

    SOA is being exploited in many various business domains. One of them is industrial maintenance. In this paper, we outline an eMaintenance Platform (eMP) for maintaining complex technical systems. This platform is part of the eMaintenance Management Framework (eMMF). Our primary goal is to explore how SOA can be exploited within industrial maintenance. Our secondary goal is to provide eMP as an effective tool for organizations to conduct their maintenance and support.

  • 31.
    Karim, Ramin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kajko-Mattsson, Mira
    Stockholm University and KTH.
    Söderholm, Peter
    Candell, Olov
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Tyrbern, Tommy
    Saab Aerotech.
    Öhlund, Hans
    Swedish Air Force Wing F21.
    Johansson, Jan
    Swedish Defence Materiel Administration.
    Positioning embedded software maintenance within industrial maintenance2008In: 2008 IEEE International Conference on Software Maintenance: [ICSM 2008] ; Beijing, China, 28 September - 4 October 2008, Piscataway, NJ: IEEE Communications Society, 2008, 440-443 p.Conference paper (Refereed)
    Abstract [en]

    Little is known about of how software embedded in complex industrial technical systems is maintained. In this paper, we identify industrial maintenance process steps and position software maintenance activities within them. We do this in the context of JAS 39 Gripen, a multi-role combat aircraft developed by Saab.

  • 32.
    Karim, Ramin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    An enterprise risk management framework for evaluation of eMaintenance2010In: International Journal of Systems Assurance Engineering and Management, Vol. 1, no 3, 219-228 p.Article in journal (Refereed)
    Abstract [en]

    Maintenance is one approach to managing risk by a reduction of the probability of failure of technical systems and/or the consequences of their failure. However, history has shown that erroneous maintenance also can lead to reduced quality, incidents and accidents with extensive losses. Today, eMaintenance promises great opportunities for a paradigm shift from a rather narrow, condition-based maintenance approach with focus on a technical system’s health to a true risk-based maintenance approach that also considers organizational excellence. This is achieved by proper information logistic solutions that address the needs of all stakeholders of the maintenance process, which are possible due to new and innovative information and com- munication technology (ICT). However, all opportunities are also linked with some threats, which are seldom high- lighted in the case of eMaintenance. In this article, a risk management framework for evaluation of eMaintenance solutions is proposed. The framework is based on a combi- nation of international standards (e.g. ISO 31000, ISO/IEC 27000, and IEC (2004) 60300-3-14) to achieve integrated Enterprise Risk Management (ERM) and enable a linkage of eMaintenance to the strategic goals of an organization. Theframework is illustrated in the railway context of Trafik- 30verket (2010b) (the Swedish Transport Administration).

  • 33.
    Karim, Ramin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Application of information and communication technology for maintenance support information services: transferring experiences from an eHealth solution in Sweden2009In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 15, no 1, 78-91 p.Article in journal (Refereed)
    Abstract [en]

    Purpose - The purpose of this paper is to explore the transferability of ICT-solutions for providing support information services from eHealth to eMaintenance. Design/methodology/approach - The applied research approach takes the form of a single-case study supported by a literature study. Empirical data were collected through documents, observations and interviews. The conclusions of the study were verified by key informants. Findings - The study indicates some major problems that have to be overcome when implementing support information services using an ICT-solution (e.g. to manage heterogeneous organizations; manage heterogeneous eService-environments; and enable context and situation awareness in eServices). Further, the study has identified and graded some solutions, which address these problems and are transferable from eHealth to eMaintenance. Practical implications - The studied case is in the forefront of eHealth solutions and can therefore act as a guidance for those involved at different stages of eHealth implementation. At the same time, eHealth is an application domain with stringent safety and security requirements, which makes the findings valuable for persons involved in support information services related to complex and critical technical systems, e.g. aircraft systems. Originality/value - The paper reports on experiences from an actual eHealth solution and not just about the concept of eHealth. Hence, it has implications for both practitioners and researchers.

  • 34.
    Karim, Ramin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Kumar, Uday
    Service-oriented condition monitoring and information logistics2009In: Proceedings of CM/MFPT 2009 - (CM2009): CD Proceedings of The Sixth International Conference on Condition Monitoring and Machinery Failure Prevention Technologies - CM/MFPT 2009, held 23-25 June 2009 at the Stillorgan Park Hotel, Dublin, Ireland, Longborough, Glos.: British Institute of Non-Destructive Testing and Coxmoor Publishing , 2009, Vol. 1, 257-267 p.Conference paper (Refereed)
    Abstract [en]

    Today the requirements on availability performance and Life Support Cost (LSC) over the system life cycle has increased and the reduction of maintenance and support cost has become more essential. To meet these requirements Condition Monitoring (CM) and Condition-Based Maintenance (CBM) can be employed. These approaches can significantly reduce Life Cycle Cost (LCC) by eliminating unnecessary inspections, minimizing inspection time and effort, and extending the useful life of new and aging components. Two important activities related to CM, that facilitates CBM, and other product support approaches, are diagnostics and its extension towards prognostics. This extension is possible thanks to new technological advances in sensors and failure analysis and is a revolution in the way complex systems can be supported. It is a breakthrough that promises not only more efficient operations and reduced maintenance cost, but also the saving of lives. However, it is not sufficient to limit the CM, diagnostic and prognostic activities to the technical systems, but the support and business systems should also be monitored and analysed to enable condition-based utilization and support of available assets and resources and fulfil ultimate performance requirements. Hence, this paper describes a service-oriented approach to CM and necessary information logistics.

  • 35.
    Klefsjö, Bengt
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    TTT-plotting: an efficient way to analyse reliability data2006In: Proceedings of the First International Conference on Maintenance Engineering, 2006, 846-854 p.Conference paper (Refereed)
    Abstract [en]

    The TTT-plot based on failure times from non-repairable units and its theoretical counterpart, the scaled TTT-transform, based on the corresponding life distribution, was presented thirty years ago as a tool for model identification purposes. Since then a number of different applications of TTT-plotting have been presented. Among these are analysis of different aging properties, optimization of age replacement problems and TTT-plotting as a source for creating and studying test statistics. Furthermore, different generalizations have been presented. Among these are applications to repairable units and use of censored failure times. This paper gives an overview of TTT-plotting and a number of practical and theoretical applications with a wide range of references for further reading.

  • 36. Lundberg, Jan
    et al.
    Parida, Aditya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Running temperature and mechanical stability of grease as maintenance parameters of railway bearings2010In: International Journal of Automation and Computing, ISSN 1476-8186, E-ISSN 1751-8520, Vol. 7, no 2, 160-166 p.Article in journal (Refereed)
    Abstract [en]

    Spherical roller bearings in railway car wheels are critical components whose failure may have catastrophic consequences. The present study aims to analyse the mechanical stability of greases and temperature of bearings as indicators for condition-based bearing maintenance. The performed case study includes nine fully-formulated commercial greases examined in the wheel bearings of five ore cars operated in northern Scandinavia. The studied ore cars travelled a distance of about 300 000 km during a period of three years. Small samples of the greases were taken on eight occasions to test their mechanical stability. In addition, the temperatures of the bearings were continuously recorded. After the test period, the wear, electrical damage, and corrosion of the bearings were examined. One of the findings is that the shear stress of the grease at a certain shear velocity (the certain yieldstress (CEY) value) is a good maintenance indicator and is highly dependent on the grease type. The bearing's wear, electrical damage and corrosion also depend on the grease type. However, no oxidation of the greases was identified. The paper also outlines a systematic methodology to determine an overall maintenance indicator for railway roller bearings which is based on the field measurements

  • 37.
    Lundberg, Jan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Mechanical stability of grease and running temperature as indicators of railway roller bearing temperature2008In: ICOMS Conference Proceedings, Surrey Hills, VIC: Asset Management Council , 2008Conference paper (Refereed)
    Abstract [sv]

    En systematisk metod för pediktering av underhållsbehov av hjullager till malmvagnar har utvecklats. Metoden bygger på merittalsberäkning och fältprov.

  • 38.
    Morant, Amparo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Gustafson, Anna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    Safety and Availability Evaluation of Railway Signalling Systems2016In: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadi; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, 303-316 p.Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is to evaluate the safety and availability of railway signalling systems using Markov models. Since a failure of the signalling systems still allows operation of the railway, it is not sufficient to study their safety and availability by considering only the failures and delays. The safety and availability are evaluated, handling both repairs and replacements by using a Markov model. The model is validated with a case study of Swedish railway signalling systems with different scenarios. The results obtained show that the probability of being in a state where operation is possible in a degraded mode is greater than the probability of not being operative at all, which reduces delays but requires other risk mitigation measures to ensure safe operation.

  • 39.
    Morant, Amparo
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Gustafson, Anna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Söderholm, Peter
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Business Administration and Industrial Engineering.
    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.
    Safety and availability evaluation of railway operation based on the state of signalling systems2017In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 231, no 2, 226-238 p.Article in journal (Refereed)
    Abstract [en]

    A framework is presented to evaluate the safety and availability of the railway operation, and quantifying the probability of the signalling system not to supervise the railway traffic. Since a failure of the signalling systems still allows operation of the railway, it is not sufficient to study their effect on the railway operation by considering only the failures and delays. The safety and availability are evaluated, handling both repairs and replacements by using a Markov model. The model is verified with a case study of Swedish railway signalling systems with different scenarios. The results show that the probability of being in a state where operation is possible in a degraded mode is greater than the probability of not being operative at all, which reduces delays but requires other risk mitigation measures to ensure safe operation. The effects that different improvements can have on the safety and availability of the railway operation are simulated. The results show that combining maintenance improvements to reduce the failure rate and increase the repair rate is more efficient at increasing the probability of being in an operative state and reducing the probability of operating in a degraded state.

  • 40. Nyström, Birre
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Improved railway punctuality by effective maintenance: a case study2005In: Advances in Safety and Reliability: proceedings of the European Safety and Reliability Conference (ESREL 2005), Tri City (Gdynia - Sopot - Gdansk), Poland, 27 - 30 June, 2005 / [ed] Krzysztof Kolowrocki, Leiden: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 2005, 1487-1491 p.Conference paper (Refereed)
    Abstract [en]

    A railway has many different requirements, such as safety and punctuality. The purpose of this studywas to explore and describe howmaintenance can contribute to improved punctuality. In an industry branch that is becoming more open, as is the case in Norway where this study was undertaken, it is important to have clear requirements and performance measures. This study has focused on railway stakeholders and their requirements regarding punctuality, the measures employed, and the traceability between requirements, goals, and measurements. Linking the end customer's punctuality requirements to reliability of the track is illustrated. The requirements flow is presented as well as a discussion about its pros and cons. The results of the study can be applied in order to compare different designs of maintenance to fulfil punctuality requirements. The information flow and the measures currently used are not entirely suitable concerning feedback and usefulness for managing availability and thus maintenance

  • 41. Nyström, Birre
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Improving railway punctuality by maintenance: a case study2005Report (Other academic)
    Abstract [en]

    A railway has many different requirements, such as safety and punctuality. The purpose of this study was to explore and describe how maintenance can contribute to improved punctuality. In an industry branch that is becoming more open, as is the case in Norway where this study was undertaken, it is important to have clear requirements and performance measures. This study has focused on railway stakeholders and their requirements regarding punctuality, the measures employed, and the traceability between requirements, goals, and measurements. Linking the end customer's punctuality requirements to reliability of the track is illustrated. The requirements flow is presented as well as a discussion about its pros and cons. The results of the study can be applied in order to compare different designs of maintenance to fulfil punctuality requirements. The information flow and the measures currently used are not entirely suitable concerning feedback and usefulness for managing availability and thus maintenance.

  • 42. Nyström, Birre
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Selection of maintenance actions using the analytic hierarchy process (AHP): decision-making in railway infrastructure2010In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 6, no 4, 467-479 p.Article in journal (Refereed)
    Abstract [en]

    A methodology for prioritising between different maintenance actions in the railway infrastructure is presented. The consistency of the prioritisation and the feasibility of the applied methodology are investigated. Criteria describing the diverse effects of maintenance are developed and presented to track managers, together with a set of maintenance actions that are specific for each track manager. Then, the analytical hierarchy process (AHP) is used to obtain preferences for the criteria and for the different actions. The track managers roughly agree on the prioritisation of criteria. However, the discrepancies between the results of the two ways employed to elicit the preferences for the actions are rather large. The track managers consider it easy to understand the rationale of the AHP and to enter their preferences. It is proposed that preferences are recorded as they are in this paper, in order to document the rationale of the decisions and to facilitate mutual learning among decision-makers and over time.

  • 43.
    Patra, Ambika Prasad
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Uncertainty estimation in railway track life-cycle cost: a case study from Swedish National Rail Administration2009In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 223, no 3, 285-293 p.Article in journal (Refereed)
    Abstract [en]

    Life cycle cost (LCC) is used as a cost-effective decision support for maintenance of railway track infrastructure. However, a fair degree of uncertainty associated with the estimation of LCC is due to the statistical characteristics of reliability and maintainability parameters. This paper presents a methodology for estimation of uncertainty linked with LCC, by a combination of design of experiment and Monte Carlo simulation. The proposed methodology is illustrated by a case study of Banverket (Swedish National Rail Administration). The paper also includes developed maintenance cost models for track.

  • 44. Patra, Ambika Prasad
    et al.
    Söderholm, Peter
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Uncertainty in life cycle cost of railway track2008In: Annual Reliability and Maintainability Symposium, 2008: RAMS 2008 ; Las Vegas, Nevada, USA, 2008, 28 - 31 Jan., Piscataway, NJ: IEEE Communications Society, 2008, 42-47 p.Conference paper (Refereed)
    Abstract [en]

    Life Cycle Cost (LCC) is used as a cost effective decision support for maintenance of railway track infrastructure. However, a fair degree of uncertainty associated with the estimation of LCC is due to the statistical characteristics of Reliability, Availability and Maintainability (RAM) parameters. This paper illustrates a methodology for estimation of uncertainty linked with LCC, by a combination of Design of Experiment (DoE) and Monte Carlo simulation. The paper also includes developed maintenance cost models for track and a case study of Banverket (Swedish National Rail Administration).

  • 45.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A requirements management approach supporting integrated health management systems design2006In: International Journal of COMADEM, ISSN 1363-7681, Vol. 9, no 2, 2-13 p.Article in journal (Refereed)
    Abstract [en]

    System health management is an approach that is intended to improve the dependability and safety of technical systems, and to decrease the combined cost of operation and support. In order to achieve the potential benefits of Health management, it is necessary to combine stakeholder requirements with a thorough engineering knowledge. The aim of this paper is to present a systemic, systematic, and stakeholder-centred Requirements Management approach that supports the design of Integrated Health Management System (IHMS). A holistic management model intended to increase stakeholder satisfaction with a reduced amount of resources in also presented. This approach is applied to a case-study related to a modern combat aircraft, which is a highly complex and critical technical system

  • 46.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    A system view of the No Fault Found (NFF) phenomenon2007In: Reliability Engineering & System Safety, ISSN 0951-8320, E-ISSN 1879-0836, Vol. 92, no 1, 1-14 p.Article in journal (Other academic)
    Abstract [en]

    When a unit is tested outside a technical system, it has normally been removed due to a fault. However, in some cases the external test may not discover any fault and a No Fault Found (NFF) event may occur. The NFF phenomenon is a major problem when dealing with complex technical systems, and its consequences may be manifested in decreased safety and dependability and increased life cycle costs. There are multiple interacting causes of NFF, demanding tough requirements for successful solutions. The purpose of this paper is to describe the phenomenon of NFF and to highlight possible improvements for the prevention of causes of NFF and the reduction of its consequences. The study was performed as an explorative literature study, and the analysis was based on a holistic system view. The identified causes and solutions are related to life cycle stages, availability performance factors, and system stakeholders.

  • 47. Söderholm, Peter
    Continuous improvements of complex technical systems: a theoretical quality management framework supported by requirements management and health management2004In: Total quality management and business excellence (Online), ISSN 1478-3363, E-ISSN 1478-3371, Vol. 15, no 4, 511-525 p.Article in journal (Refereed)
    Abstract [en]

    Continuous Improvements are a core value of Quality Management. This work is often a response to changed stakeholder requirements. However, the increasing complexity and criticality of many of today's technical systems require that the improvement work is systematic in order to manage properly the changes and avoid unwanted effects. This paper explores how Requirements Management and Health Management can support Quality Management, in order to systematize the management of continuous improvements of complex technical systems in response to changed stakeholder requirements. The result is a theoretical management framework based on a combination of the three management areas. The framework is intended to facilitate a systematic work with continuous improvements of complex technical systems, in the context of dynamic stakeholder requirements.

  • 48. Söderholm, Peter
    Continuous improvements of complex technical systems: aspects of stakeholder requirements and system functions2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In today's society we are all strongly dependent on correct functions of technical systems. These systems tend to increase in both complexity and criticality, at the same time as they often have a rather long life. During this long life the stakeholders' requirements on the functions of the systems change. In order to maintain a high level of stakeholder satisfaction organisations responsible for the system have to respond to the changes through system development and continuous improvements. When the technical system is both complex and critical it is even more important that the work with continuous improvements is done in a systemic and systematic way. This is because a modification may result in unwanted side effects and a small change in one part of the system may have a major negative impact on many other parts of the system, and also have far reaching decisive consequences. The purpose of this thesis is to explore and describe how an organisation can work with continuous improvements of complex technical system functions in the context of changing stakeholder requirements, in order to increase stakeholder satisfaction with a reduced amount of resources. To fulfil the stated purpose a case study supported by a literature study has been made. The case study focused on a modern combat aircraft, which is considered as a highly complex and safety critical system with stringent requirements on low life cycle cost. The result of the study may be described in two parts. The first part is a theoretical management framework that combines aspects of Quality Management, Requirements Management, and Health Management. The framework describes on a conceptual level how the work with continuous improvements may be enhanced through synergism achieved by the combination. The second part, which is based on both theoretical and empirical findings, is a model intended to support the work with continuous improvements. The model includes a number of combined and adapted methodologies and tools that enable traceability between stakeholder requirements and the critical system functions that should be covered by tools that support Condition Monitoring, Diagnostics, and Prognostics.

  • 49.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Maintenance and continuous improvement of complex systems: linking stakeholder requirements to the use of built-in test systems2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The failure of a technical system represents two different kinds of change. One change is the degradation of system functions, while the other change is the increase in stakeholder requirements. Hence, information about both stakeholder requirements and system health are necessary in order to properly manage system failures. This management includes a combination of maintenance and improvement efforts. The combination is especially crucial when dealing with complex and critical systems, where a change may result in unwanted consequences with extensive losses. In this situation, maintenance and improvements can be supported by the use of Built-in Test systems, which aim at enhanced testability and maintainability performance of the technical system. The purpose of this research is to explore and describe the linking of changing stakeholder requirements to the use of Built-in Test systems, in order to facilitate maintenance and continuous improvement of complex and critical systems. To fulfil the stated purpose two case studies and one pilot study, supported by a continuous literature study have been made. The main case study and the pilot study focused on a modern combat aircraft, which is considered as a highly complex and safety critical system with stringent requirements on low life cycle cost. The second case study focused on maintenance-related requirements and risks during maintenance execution within a paper-mill, which is a complex system with stringent requirements for uninterrupted production. The research is presented in this thesis, which consists of an extended summary of five journal papers that are appended in full. The thesis includes examinations of important stakeholders and their requirements of critical system health information. Furthermore, the thesis includes studies and analyses of hazards related to health information retrieved through Built-in Test systems and combined with information from external test systems. The thesis also provides suggestions for how stakeholder requirements can be linked to the use of Built-in Test systems, so that they together with external test systems provide required health information and reduce related hazards.

  • 50.
    Söderholm, Peter
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Akersten, Per-Anders
    Aerospace diagnostics and prognostics in a TQM-perspective2002In: Condition monitoring and diagnostic engineering management: proceedings of the 15th international congress, 2nd - 4th September 2002, Birmingham, UK / COMADEM / [ed] Raj B. K. N. Rao; Asoke Kumar Nandi, Birmingham: COMADEM International, 2002, 80-89 p.Conference paper (Refereed)
12 1 - 50 of 61
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