| 1. |
- Anandika, Rayendra, 1988-, et al.
(författare)
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Non-destructive measurement of artificial near-surface cracks for railhead inspection
- 2019
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Ingår i: Insight. - UK : The British Institute of Non-Destructive Testing. - 1354-2575 .- 1754-4904. ; 61:7, s. 373-379
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Tidskriftsartikel (refereegranskat)abstract
- This paper delivers a study involving the inspection of artificial surface cracks with depths ranging from 0.25-2.5 mm from the surface and with a crack angle of 30°, which is a typical angle for surface cracks in railheads. The inspections were conducted using three different techniques: phased array ultrasonics, single-element ultrasonics and alternating current potential drop (ACPD). For the ultrasonic techniques, the study focused on employing either longitudinal or shear wave signals. In the railway industry, shallow surface cracks in railheads are caused by rolling contact fatigue (RCF). In this study, artificial defects were made, allowing the authors to explore the extent to which the ultrasonic measurement techniques can detect such defects. The negative effect of a dead zone near to the surface in the ultrasonic tests was reduced by using a wedge attachment. A discussion on the extent to which the techniques can be used in field tests was also provided. The most important result is that shallow cracks ranging from 0.25-2.5 mm were successfully characterised with acceptable accuracy. The 2.5 mm-deep crack can be measured with an accuracy of 0.8% using a 20 MHz single-element probe and with an accuracy of 3.5% using a 5 MHz phased array (64 elements, 0.6 mm pitch). The characterisations were performed using a filtering method that was developed in this study.1675605
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| 2. |
- Anandika, Rayendra, 1988-, et al.
(författare)
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Phased array ultrasonic inspection of near-surface cracks in a railhead and its verification with rail slicing
- 2020
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Ingår i: Insight. - United Kingdom : The British Institute of Non-Destructive Testing. - 1354-2575 .- 1754-4904. ; 62:7, s. 387-395
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Tidskriftsartikel (refereegranskat)abstract
- In this study, near-surface cracks in a railhead are inspected thoroughly using phased array ultrasonic testing (PAUT). This research finds an alternative technique to inspect for near-surface cracks because the conventional non-destructive testing method for rail inspection lacks the capacity to inspect the near-surface crack profile. This study shows that PAUT can determine not only the crack depth but also the near-surface crack profile, so that the inspector can estimate the stage of crack growth and how the crack propagates. This information is valuable to the rail maintainer as one of the considerations for deciding the thickness of metal to remove when grinding the rail. In this study, after the measurement, the inspected region of the cracked railhead is sliced into thin pieces so that crack network information can be extracted. A 3D image reconstruction of the surface cracks based on the crack marks from all of the sliced rail pieces is performed. This image is then used as a reference to confirm the PAUT results. The results show that PAUT can clearly deliver crack profile estimation and provide an accurate estimation of a 3.51 mm crack-tip depth with an absolute error range of 8%-18%. The results also suggest that PAUT is a potential method for installation in a measurement train for near-surface crack inspection.
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| 3. |
- Anandika, Rayendra, 1988-, et al.
(författare)
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Ultrasonic phased array measurement of near-surface cracks in the railhead.
- 2019
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Ingår i: World Congress on Railway Research (WCRR) 2019, Tokyo, Japan. - : Railway Technical Research Institute (RTRI, Japan).
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Konferensbidrag (refereegranskat)abstract
- Ultrasonic measurement is one of the non-destructive techniques used to inspect defects in the rail body. Ultrasonic measurement is known inappropriate to inspect near-surface defects because of a challenge, called dead-zone. It is signal noise or ringing phenomenon located at near-field in front of the transducer when measuring a material. Due to this, there is difficulty in analysing any measurement signal at this zone, including signals from near-surface defects. In this study, the dead zone was eliminated by attaching wedge to shift the location of noise signals relative to the near-surface defect locations. First, a known-depth defect was measured by using phased array ultrasonic testing (PAUT) to calibrate the ultrasonic equipment and found the best signal gain to eliminate diffuse scattering from defects. Second, a cracked spot on railhead was inspected at the right and left direction of the spot. After the measurement, the inspected spot was sliced into 0.65 mm-thick pieces. From those pieces, the actual crack depth could be observed directly. Based on those sliced pieces, the ultrasonic measurement results were verified. From this study, PAUT delivered accurate measurement result of 3.51-mm crack tip depth with an absolute error of 0.8% - 18%. This accurate result indicates that PAUT can be an alternative to inspect the near-surface crack in railhead.
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| 4. |
- Berges, Luis, et al.
(författare)
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Qualitative and quantitative aspects of maintenance performance measurement: a data fusion approach
- 2013
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Ingår i: International Journal of Strategic Engineering Asset Management (IJSEAM). - 1759-9733 .- 1759-9741. ; 1:3, s. 238-252
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of maintenance performance is often faced with a lack in knowledge about the real function of the maintenance department within organisations, and consequently appropriate targets from the global mission and vision are absence. Measurement metrics are not adapted to real needs, which have a strong human factor; nor is there a roadmap of the amount of data to be collected, their processing or how they are used in decision making. This article proposes a model where qualitative and quantitative methods are combined to complement the advantages of both.
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| 5. |
- Eriksson, Kjell, et al.
(författare)
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Homogenization of the 1D Peri-static/dynamic Bar with Constant Micromodulus
- 2020
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Ingår i: Journal of Peridynamics and Nonlocal Modeling. - : Springer. - 2522-896X .- 2522-8978. ; 2:2, s. 205-228
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Tidskriftsartikel (refereegranskat)abstract
- Because of the nonlocal interparticle forces inherent in peridynamics, surface, boundary, and end effects appear in 3D, 2D and 1D body problems, respectively. In certain situations, the effect is seen as a disturbance, and various efforts, mostly centering on 2D and 1D problems, have been made to reduce it. A simple method has been derived to remove the end effects in a 1D body by homogenizing the body. When a certain body type, common in practice, is homogenized, its linear elastic behavior, independent of the interparticle force range and with a finite number of material points, in the limit infinite, is identical to that of a corresponding classical continuum mechanics body.
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| 6. |
- Eriksson, Kjell, et al.
(författare)
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Homogenization of the 1D Peri-static/dynamic Bar with Triangular Micromodulus
- 2021
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Ingår i: Journal of Peridynamics and Nonlocal Modeling. - : Springer. - 2522-896X .- 2522-8978. ; 3:2, s. 85-112
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Tidskriftsartikel (refereegranskat)abstract
- In peridynamics, boundary effects generally appear due to nonlocality of interparticle forces; in particular, end effects are found in 1D bars. In a previous work by Eriksson and Stenström (J Peridyn Nonlocal Model 2(2):205–228, 2020), a simple method to remove end effects in certain types of 1D bars, or to homogenize such bars, was presented for bars with constant micromodulus. In this work, which is a continuation of Eriksson and Stenström (J Peridyn Nonlocal Model 2(2):205–228, 2020), the homogenizing procedure is applied to bars with a linear, or “triangular,” micromodulus. For the examples studied, common in practice, the linear elastic behavior of a homogenized bar, is identical to that of a corresponding classical continuum mechanics bar, independently of the interparticle force range and total number of material points of the bar.
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| 7. |
- Famurewa, Stephen Mayowa, et al.
(författare)
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Composite indicator for railway infrastructure management
- 2013
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Konferensbidrag (refereegranskat)abstract
- The assessment of efficiency and effectiveness of past maintenance decisions and actions is an essential element in maintenance process. The significance of this is not only limited to communicating the value contribution of maintenance to overall business objectives but also to drive maintenance for improvement and towards excellence. However the existence of numerous maintenance result areas and many operational level indicators often lead to distributed information that is not in a suitable format required to support decision making. This paper motivates the use of fuzzy logic approach to aggregate selected indicators to appreciate the information bit distributed in each indicator. The selected indicators include measures related to safety, comfort, punctuality, availability and reliability aspects of maintenance. Linguistic description and fuzzy sets are developed for each of the indicators which are regarded as input parameters. Also domain experts are employed to develop inference rules for the aggregation process. The methodology of using fuzzy inference system for aggregating maintenance performance indicators is demonstrated with selected line sections of Trafikverket (Swedish Transport Administration). The resulting composite indicator gives a reliable quantification of the health condition of the asset and performance of maintenance within the period under consideration. This can be easily communicated and benchmarked within the organization of the infrastructure manager.
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| 8. |
- Famurewa, Stephen Mayowa, et al.
(författare)
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Composite indicator for railway infrastructure management
- 2014
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Ingår i: Journal of Modern Transportation. - : Springer Science and Business Media LLC. - 2095-087X .- 2196-0577. ; 22:4, s. 214-224
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Tidskriftsartikel (refereegranskat)abstract
- The assessment and analysis of railway infrastructure capacity is an essential task in railway infrastructure management carried out to meet the required quality and capacity demand of railway transport. For sustainable and dependable infrastructure management, it is important to assess railway capacity limitation from the point of view of infrastructure performance. However, the existence of numerous performance indicators often leads to diffused information that is not in a format suitable to support decision making. In this paper, we demonstrated the use of fuzzy inference system for aggregating selected railway infrastructure performance indicators to relate maintenance function to capacity situation. The selected indicators consider the safety, comfort, punctuality and reliability aspects of railway infrastructure performance. The resulting composite indicator gives a reliable quantification of the health condition or integrity of railway lines. A case study of the assessment of overall infrastructure performance which is an indication of capacity limitation is presented using indicator data between 2010 and 2012 for five lines on the network of Trafikverket (Swedish Transport Administration). The results are presented using customised performance dashboard for enhanced visualisation, quick understanding and relevant comparison of infrastructure conditions for strategic management. This gives additional information on capacity status and limitation from maintenance management perspective.
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| 9. |
- Faxén, Karl-Filip, et al.
(författare)
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Multicore computing--the state of the art
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document presents the current state of the art in multicore computing, in hardware and software, as well as ongoing activities, especially in Sweden. To a large extent, it draws on the presentations given at the Multicore Days 2008 organized by SICS, Swedish Multicore Initiative and Ericsson Software Research but the published literature and the experience of the authors has been equally important sources. It is clear that multicore processors will be with us for the foreseeable future; there seems to be no alternative way to provide substantial increases of microprocessor performance in the coming years. While processors with a few (2–8) cores are common today, this number is projected to grow as we enter the era of manycore computing. The road ahead for multicore and manycore hardware seems relatively clear, although some issues like the organization of the on-chip memory hierarchy remain to be settled. Multicore software is however much less mature, with fundamental questions of programming models, languages, tools and methodologies still outstanding.
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| 10. |
- Fecarotti, Claudia, et al.
(författare)
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Requirements and Initial Concept for an Asset Management Framework
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This document constitutes the first issue of Deliverable D6.2 ‘Requirements and initial concept for an asset management framework’ in the framework of the project titled ‘Innovative Intelligent Rail’ (Project Acronym: In2Rail; Grant Agreement No 635900).This document has been prepared to provide the requirements and initial concept of a comprehensive framework for performance prediction, modelling and decision support for railway asset management, taking into account UIC asset management (AM) guidelines, rail infrastructure performance and constraints on resources and the supply chain. Two objectives guide the work: developing a key performance indicator (KPI) decision framework and defining a framework for performance prediction, modelling and decision support.Based on interviews and a study of previous work, including In2Rail D6.1, a KPI decision framework has been constructed, fully compliant with UIC AM guidelines, and an adapted KPI definition guide has been applied to two case studies. Specifically, the KPI definition guide has been used to exemplarily define availability KPI and risk matrix KPI in the context of rail transportation, using 36 questions to define the indicators and 10 questions to verify them. The KPIs are demonstrated using infrastructure managers’ (IMs) records of operation and maintenance.The developed framework constitutes a comprehensive modelling structure for describing, analysing, and optimising asset management decisions on a whole-life, whole-system basis. It defines a systematic approach to analysing the effects of any intervention plan and produces performance, risk and cost profiles that can be used as decision support. The framework will facilitate the assessment and development of intervention plans in three planning stages: strategic, tactical and operational. In this sense, the framework is fully compliant with ISO 55001, complementary to the UIC AM framework, and aligned with the Intelligent Asset Management System (IAMS) developed in In2Smart leverabel D2.1.
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