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  • 501.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Application of the sound method for characterisation of engine noise sources1994Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 502.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Energieffektivisering genom flödesexciterad, resonansförstärkt och ultraljudskontrollerad kavitation: Delprojekt inom Mekmassainitiativet för energieffektivitet (E2MPi)2016Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Projektet syftar till att öka kunskap och förståelse för hur kavitation kan användas och kontrolleras för att koncentrera bearbetningsenergin till frekvensområden som ger effektiv påverkan av cellulosafibrer. Tanken är att skapa ett komplement eller en alternativ teknik till dagens raffinörer. Idén bygger på att resonansförstärkt ultraljud initierar och kollapsar kavitationsbubblor på ytan av cellulosafibrer i vatten. Tidigare forskning har visat att ultraljudsbehandling ger önskade effekter på fiberväggen. Energieffektiviteten har dock inte varit tillräckligt bra och uppskalning är en identifierad problematik. Den föreslagna metoden syftar till att via numerisk och experimentell optimering åstadkomma en energieffektiv och kontrollerad bearbetning av fiberväggen. Den långsiktiga målsättningen är att halvera energiförbrukningen i jämförelse med dagens raffinörer.Hypotesen är att ultraljudskontrollerad kavitation fungerar beroende på att transient asymmetrisk kollapsa av kavitationsbubblor kan ge upphov till extrema tryck på en liten yta. Principen bygger på små att gasbubblor i vatten exciteras av högintensivt ultraljud. Vid en viss kritisk storlek kommer bubblan i resonans och då växer den snabbt. Yttre trycket når sitt max i samband med att bubblan kollapsar. Ultraljud med konstant frekvens (ex 20 kHz) gör att mängder av bubblor, med varierande storlek och harmoniskt relaterade resonansfrekvenser, kollapsar. De jetstrålar i mikroskala som uppstår vid asymmetrisk kollaps av kavitationsbubblor antas ge en mekanisk påverkan av cellulosafibrer i form av både inre och yttre fibrillering.Projektet har resulterat i en utveckling och verifiering av en FE-baserad optimeringsstrategi för flödesinducerad och ultraljudskontrollerad kavitation. Den framtagna kavitationsreaktorn består av en dysa och ett vattenfyllt reaktorrör exciterat med ultraljud. Fibersuspensionen strömmar genom ett inre tunnväggigt rör i reaktorns centrum. Beräkningsmodellen ger stabila resultat avseende ultraljudsexcitering och är kalibrerad med experimentellt bestämda förlustfaktorer för aktuell prototypreaktor. Simuleringar av flödesinducerad kavitation begränsades till ren vattenfas. Den framtagna geometrin är dock verifierad avseende strömning med fibersuspension. Experimentella resultat utan flöde visar mycket god överenstämmelse avseende beräknade svängningsformer och resonansfrekvenser. Beräknad ljudtrycksnivå är högre än uppmätt beroende på de olinjäriteter som uppstår när vätskan utsätts för mycket höga amplituder. Dessutom är förlustfaktorn något högre i experimenten och trycksignalens verkliga effektinnehåll ligger delvis utanför mätområdet.Beräkningsjämförelser med ett alternativt och kommersiellt förekommande reaktorkoncept (behållare), visar att den nyutvecklade rörreaktorn ger högre intensitet i den optimala zonen (+120%). Den totala förlustfaktorn för rörreaktorn är ca 1.1 % vid resonans. Tillförd elektrisk effekt bestäms genom att mäta ström och spänning när kavitationsreaktorn exciteras vid sin resonansfrekvens. Optimal kavitationseffekt identifieras av ljudtrycksamplitudkvoten: pUS(f1.5)/pUS(f1). Kavitation ger effektiv bearbetning av fibermaterialet i zonen för maximal tryckvariation. Initiering av flödesinducerad kavitation med justerbar Venturi-dysa ger intensivare kavitation samt god blandning och sammanhållen fibersuspension. Test och verifiering med fibermaterial är baserad på en HT-CTMP fiber (torkad/aldrig torkad) med 0.5%, 1% och 2% konc. Positiv förändring av fiberkvalitet uppstod endast i några av testfallen. I test med både flödesinducerad och ultraljudsstyrd kavitation uppstod bäst resultat vid lägst energinivå (470 kWh/adt). I övriga testfall finns misstanke om att fibermaterialet har förstörts av för hög kavitationsintensitet. En slutsats som delvis verifieras av SEM-analys av behandlat fibermaterial. Tillförd energinivå var dock inte tillräcklig för att uppnå godkänd massakvalitet, dvs. lika bra eller bättre dragindex. I nuläget går det inte att fastställa om föreslagen metod är energieffektiv på grund av svårigheten i att jämföra en prototyp och fullskaleanläggning. En uppenbar förbättringsmöjlighet med framtagen reaktorlösningen är att förlänga reaktorröret (ej realiserbart i prototypskedet). Den valda reaktorlösningen kan skalas upp genom parallellkoppling och seriekoppling. Seriekoppling och längre reaktorrör kräver ett högre matningstryck vilket kan ge en fördel med högre kavitationsintensitet. Den experimentella valideringen är begränsad till en excitationsfrekvens (22.7 kHz) och normaltryck. En kombination med högre ultraljudsfrekvenser (37 och/eller 53 kHz för rörreaktorn) är en möjlig förbättring genom att de aktiva bubblornas storlek reduceras och får en storleksordning som är bättre anpassad till fiberväggens storlek och struktur. En annan förbättringsaspekt är ett högre statiskt tryck, vilket ökar kavitationsintensiteten och möjliggör en förkortad exponeringstid.

  • 503.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Experimental and multivariate analysis methods for sound quality evaluation of diesel engines1996Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Noise control and sound quality analysis are important, since noise has been registered to be a predominant factor in stress and a source of great annoyance. Traffic noise is a problem and a major part of this noise comes from heavy vehicles. The only legislative requirement for heavy-duty trucks regarding noise emissions, is that the noise level does not exceed an Aweighted sound pressure level of 80 dB. The specification of an A-weighted sound pressure level is, however, not an adequate description of psychoacoustic annoyance and therefore work towards defining a better description of loudness is one of the principal fields of acoustics today. Sound radiation from trucks is speed-related. At medium and high speeds, the overall noise level is comprised mainly of the tyre noise, whereas at low speed and during acceleration, exhaust noise and noise from the engine and transmission structure are predominant. In front of the truck, the noise from the engine and especially that from the timing transmission cover, the torsional damper and the oil sump, comprises a greater proportion of the total noise. The aim of sound quality analysis of diesel engines is to find cost-efficient methods of reducing sound radiation and of changing the character of the sound in order to minimise annoyance. This thesis concerns the development of experimental methods for analysing the sound quality of diesel engines, and focuses on measurement of acoustic intensity, multivariate data analysis, structural modification and subjective assessment of engine noise. The applicability of the FFT-based sound intensity method is evaluated. It is found that the intensity measurements may be influenced by high reactivity, interference due to partlycoherent sources, difficulties in performing the spatial average, real-time limitations and engine speed variations. Scanning the intensity probe, preferably by a robot, is necessary when measuring within narrow bands to avoid interference problems. Scanning achieves more reliable estimates of sound power and intensity vectors. Experimental design and the multivariate techniques, principal components analysis (PCA) and partial least squares (PLS) were utilised to facilitate interpretation of intensity measurements. The results show that PCA and PLS enable independent phenomena in the sound field to be extracted and which can thereby be visualised by principal spectra and principal radiating patterns. The characteristics of sound radiation are determined by designed experiments, sound intensity measurements and operational deflection shape estimations. These methods enable the effects on sound radiation of structure modifications to be predicted. An annoyance index for in-line 6-cylinder diesel engines in stationary running conditions was developed using multivariate statistics. The index is based on engine sounds resulting from structure modifications and changes in fuel. The annoyance level was measured during listening tests of sound stimuli recorded in stereo and reproduced by loudspeakers under anechoic conditions. The different sound stimuli were ranked using paired comparisons or the method of successive intervals. It was found that 94% of the variance of annoyance can be explained by a model based on loudness (Sone), sharpness (Acum) and harmonic ratio (rumble). Impulsiveness, roughness and tonality were other important criteria used in the study and which were found to have a relationship with specific speed ranges. The annoyance was minimised by an increase in stiffness in the lower part of the engine achieved by using a ladder frame in combination with a bearing beam.

  • 504. Johansson, Örjan
    et al.
    Johnsson, Roger
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sound intensity measurements of transient noise in presence of extraneous noise2003Ingår i: Inter-Noise 2003, the 32nd International Congress and Exposition on Noise Control Engineering: August 25 - 28, 2003, International Convention Center Jeju, Seogwipo, Korea, Seoul: International institute of noise control engineering , 2003Konferensbidrag (Refereegranskat)
  • 505. Johansson, Örjan
    et al.
    Kahn, M.S.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sound quality assessment of a diesel engine due to structure modifications1996Ingår i: Noise control - the next 25 years: proceedings, St Albans: Institute of Acoustics , 1996Konferensbidrag (Refereegranskat)
  • 506.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Liljergren, M.
    Sound localisation using hearing protectors2006Ingår i: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 92, nr suppl 1Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Using a hearing protective device, feedback from the surroundings is of importance. Three aspects to be considered is the ability to communicate orally, the possibility to localize sound sources and to obtain a natural impression of the sounding environment. This could only be achieved by using a protective device that allow acoustic feedback, typically by a pair of microphones attached to the cup of each ear. The microphone signal is fed via an amplifier and an electronic compressor, that limit the amplitude of the signal fed to the loud speakers inside the cups. Typical problems with this type of solution are that the signals received by the two ears are distorted so much that sound localisation is difficult and that the sound is perceived unnatural. The objective of the project is to optimise the cup geometry especially where the microphones are mounted, and by that improve sound localisation and minimise the amplification of non-important weak sounds like the foot step of the user

  • 507.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lindegren, David
    Luleå tekniska universitet.
    Analysis of everyday sounds which are extremely annoying for children with autism2008Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, nr 5, s. 3299-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Extreme sensitivity to noise is a problem that almost all autistic children suffer from. A sound that is extremely annoying does not need to be loud. However, the characteristics and temporal variations of these sounds are sparsely investigated. The aim of this study is to increase the knowledge about these extremely annoying sounds so they can be avoided by better design criteria for classrooms and venues like that. By interviewing teachers and parents a number of everyday sounds were identified and binaurally recorded. Examples are vacuum cleaners, ventilation noise, washing machines and pouring water. Detailed psychoacoustic analyses of this type of sounds were achieved by a listening test procedure in three parts. First 16 children composed different types of vacuum cleaner sounds trying to minimize annoyance in two different tests, a) keeping original sound pressure level. b) adjusting to acceptable loudness. In the second part, teachers working with autistic children performed a listening test to evaluate some of the composed sounds from part 1 and modified versions of them. The third part was performed by children to validate the results. The results showed that Roughness, Loudness and an index defined as High frequency tonality were the most important characteristics.

  • 508.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pamidi, Taraka Rama Krishna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Design of high-intensity ultrasound reactor2017Ingår i: IEEE International Ultrasonics Symposium, IUS, Piscataway, NJ: IEEE Computer Society, 2017, artikel-id 8092948Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design and optmiziation of ultrasonic reactors are important objectives in sonochemical processing. The recent expansion of the use of ultrasonic reactors in various research projects all faces the problem of scaling up laboratory results for industrial use. A traditional ultrasonic reactor usually has several issues, such as low effectiveness and complex and unstable system performance, which all are unfavorable for efficient sonochemical processing. This study adresses these issues and investigates a new flow type ultrasonic reactor designed to generate transient cavitation as the main source for ultrasound for sonochemical processing. This study proposes the principle of the flow type ultrasonic reactor design to generate transient cavitation. The objective of this work is to design an ultrasonic reactor with a new geometry. The idea is to improve process efficiency based on resonance enhanced ultrasound controlled cavitation

  • 509.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pamidi, Taraka
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Khoshkhoo, Mohammad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sandström, Åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sustainable and energy efficient leaching of tungsten(W) by ultrasound controlled cavitation2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The project aims to use ultrasound controlled cavitation to achieve a more energy efficient leaching process. Locally, collapsing cavitation bubbles cause an extremely high pressure, shock waves and high temperature, which provide an opportunity to perform the leaching process at a much lower temperature than in an autoclave (20 bar overpressure and 220 ° C). The results show that the method works, but that a higher static pressure and thus temperatures are necessary to achieve a leaching recovery rate corresponding to today's autoclave technology. Another process parameter of importance is flow control and the initiation of cavitation bubbles that occur through a geometrically optimized nozzle (orifice plate). Numerical and experimental adaptation of the developed reactor with respect to the leaching conditions (Sodium hydroxide and Scheelite concentrate), required more time than expected. Best test results show that an energy supplement with ultrasonic controlled cavitation of 104 kWh / kg increases the leaching recovery by 21%. The leaching reagent temperature 60° C was determined regarding available reference data and was thought to be close to optimum for intensive cavitation in atmospheric pressure. Optimum temperature relates to the leaching reagent, vaporization temperature, density, boiling point, surface tension, and viscosity. Generally, for leaching is that higher temperatures are required to increase the chemical reaction rate (requires overpressure). The modified reactor principle provides stable results and is possible to scale up. Higher cavitation intensity for shorter finishing time and higher recovery rate require advanced flow induction, multiple excitation frequencies adapted to the optimized reactor geometry, as well as optimal process pressure and temperature.

  • 510.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pamidi, Taraka Rama Krishna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Shankar, Vijay
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Acoustic design principles for energy efficient excitation of a high intensity cavitation zone2019Ingår i: Proceedings of the 23rd International Congress on Acoustics, integrating 4th EAA Euroregio 2019: ICA 2019, 9 - 13 September / [ed] Martin Ochmann, Aachen, Germany, 2019, s. 948-955Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Energy-efficient process intensification is a key aspect for a sustainable industrial production. To improve energy conversion efficiency high intensity cavitation is a promising method, especially in cases where the material to be treated is valuable and on the micro meter scale. Transient collapsing cavitation bubbles gives powerful effects on objects immersed in fluids, like cellulose fibers, mineral particles, enzymes, etc. The cavitation process needs optimization and control, since optimal conditions is multivariate challenge. This study focuses on different design principles to achieve high intensity cavitation in a specific volume in a continuous flow. This study explores some potential design principles to obtain energy efficient process intensification. The objective is to tune several different resonance phenomena to create a powerful excitation of a flowing suspension (two-phase flow and cavitation bubbles). The reactor is excited by sonotrodes, connected to two coupled resonant tube structures, at the critical frequency. Finally cavitation bubbles are initiated by a flow through a venturi nozzle. The acoustically optimised reactor geometry is modelled in Comsol Multiphysics®, and excited by dedicated ultrasound signals at three different frequencies. The effect of the high intensity cavitation is experimentally evaluated by calorimetric method, foil tests and degree of fibrillation on cellulose fibers.

  • 511.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schönfeld, Stephan
    ÅF-Infrastructure AB.
    Lindforss, Daniel
    ÅF-Infrastructure AB.
    Sound sketch procedure for auralization of the interior sound of a high speed train2012Ingår i: Proceedings of Inter-Noise 2012: held in conjunction with the annual meeting of the Noise Control and Acoustics Division of the American Society of Mechanical Engineers ; New York, New York, USA, August 19 - 22, 2012 / [ed] Courtney Burroughs, Washington, DC: International institute of noise control engineering , 2012Konferensbidrag (Övrigt vetenskapligt)
  • 512. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A study of the interaction effects between the torsional vibration damper and engine structure by gated measurements1994Ingår i: Noise - quantity and quality: proceedings / The 1994 International Congress on Noise Control Engineering, Inter-Noise 94 ; Yokohama, Japan, August 29 - 31, 1994, Poughkeepsie, NY: Noise control foundation , 1994, s. 395-398Konferensbidrag (Refereegranskat)
  • 513. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Noise radiation from a torsional vibration damper in a diesel engine1993Ingår i: People versus noise: proceedings of the 1993 International congress on noise control engineering, Inter-Noise 93 / [ed] Pierre Chapelle; Gerrit Vermeir, Poughkeepsie, NY: Noise control foundation , 1993Konferensbidrag (Refereegranskat)
  • 514. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Noise radiation from the torsional damper in a diesel engine: an investigation of the interaction effect between the torsional damper and the timing cover1992Rapport (Övrigt vetenskapligt)
  • 515. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    The use statistical methods to predict the noise radiation from a torsional vibration damper in a diesel engine1993Rapport (Övrigt vetenskapligt)
  • 516. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lindberg, W.
    Luleå tekniska universitet.
    Principal components and partial least squares modelling of sound intensity measurements1995Ingår i: Proceedings of the 15th international congress on acoustics: Trondheim, Norway, 26-30 June 1995, Trondheim: Tapir Akademisk Forlag, 1995Konferensbidrag (Refereegranskat)
  • 517. Johansson, Örjan
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sundbäck, Ulrik
    Luleå tekniska universitet.
    Klopotek, Manfred
    Luleå tekniska universitet.
    Source characterization of the lower front-end of a diesel engine1996Ingår i: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 49, nr 4, s. 383-404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lower front end of a diesel engine is a major noise source. Describing the source mechanisms of this area is problematic as it consists of a rotating torsional vibration damper in front of the timing transmission cover and the oil sump. This experimental study focuses on the acoustic interaction phenomena between the damper and the structure behind it. To describe the source mechanisms a test series of different modifications by conventional lead wrapping technique is performed. The vibration behaviour of each substructure is determined by operational deflection shape measurements and the source strength for each modification is determined by near-field sound intensity measurements. The results show the contributions from different substructures and describes the interference effects due to coherent radiation. It is concluded that the radiation is dominated by the timing transmission cover structure behind the damper. At some frequencies though, the torsional vibration damper in combination with the timing transmission cover behind it, causes the high radiation. This effect is mainly due

  • 518.
    Johnsson, Roger
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Acoustic vehicle alerting systems: Will they affect the acceptance of electric vehicles?2018Konferensbidrag (Refereegranskat)
  • 519.
    Johnsson, Roger
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Crankshaft speed measurements and analysis for control and diagnostics of diesel engines2001Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The increasing demands from governments on the engine manufactures to lower the fuel consumption, lower the exhaust emissions and to reduce the noise have lead to an intensive research in the combustion process. Measurement of the combustion process inside the cylinder is only suitable in laboratory environment due to a number of limitations; the pressure transducer needed to measure the pressure is expensive, difficult to mount in the cylinder and has a limited lifetime that is much shorter than the engine's lifetime. Demands of on-board diagnostics where the combustion process is continuously monitored, on production vehicles have created a need for a method to indirectly measure the combustion process. The two main indirect methods are vibration measurement based reconstruction and crankshaft angular speed measurement reconstruction. The combustion process give rise to vibrations in the engine body that in the former method is measured with an accelerometer and the pressure can be reconstructed by using inverted transfer functions. The idea behind the latter method, the crankshaft angular speed reconstruction method, is that when one cylinder fires the produced torque is higher than the load torque and the crankshaft accelerates. As next cylinder goes into compression the total load torque increases and the crankshaft speed will decrease. This is repeated when the next cylinder fires and the produced crankshaft speed fluctuations will then contain information about the combustion and compression that caused it. In this thesis an indirect method to predict the maximum cylinder pressure is developed based on the crankshaft speed fluctuations combined with neural networks. The speed fluctuations were measured on a 6-cylinder inline diesel engine at 9 speed-load-combinations. A two layer (one hidden and one output layer) feedforward neural network was trained with the backpropagation algorithm. The prediction accuracy for pmax was found to be better than ±5 % at 95%-confidence interval for the validation set. Another important parameter for the engine control and for optimising the fuel efficiency at the same time as the exhaust emissions are kept to a minimum, is the position of the pistons most upper position, TDC (top dead centre). The TDC position is normally measured mechanically with means that need access to the cylinders (the cylinder head has to be removed). This method is time consuming and therefore expensive and because of that not used on production engines. Several indirect methods to measure the TDC- positions have been suggested. Either based on measured cylinder pressures, that again need a pressure transducer mounted in the cylinder, or on the crankshaft speed fluctuations. An indirect method based on the speed fluctuations, that are measured when the starter motor rotates the engine with turned off ignition, is developed. From the measured crankshaft speed fluctuations the TDC-positions can be determined either by curve fitting or with neural networks. The TDC position determined by curve fitting has a bias error, due to the out-of-phase acceleration component in the crankshaft that are induced by the starter motor, but also caused by heat exchange between the compressed gas and the cylinder walls and gas. The results from the neural network were found to be better and the TDC-position for all 6 cylinders was determined within ±0.1 degree crank angle at 95%-confidence interval.

  • 520.
    Johnsson, Roger
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Cylinder pressure reconstruction based on complex radial basis function networks from vibration and speed signals2006Ingår i: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 20, nr 8, s. 1923-1940Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Methods to measure and monitor the cylinder pressure in internal combustion engines can contribute to reduced fuel consumption, noise and exhaust emissions. As direct measurements of the cylinder pressure are expensive and not suitable for measurements in vehicles on the road indirect methods which measure cylinder pressure have great potential value. In this paper, a non-linear model based on complex radial basis function (RBF) networks is proposed for the reconstruction of in-cylinder pressure pulse waveforms. Input to the network is the Fourier transforms of both engine structure vibration and crankshaft speed fluctuation. The primary reason for the use of Fourier transforms is that different frequency regions of the signals are used for the reconstruction process. This approach also makes it easier to reduce the amount of information that is used as input to the RBF network. The complex RBF network was applied to measurements from a 6-cylinder ethanol powered diesel engine over a wide range of running conditions. Prediction accuracy was validated by comparing a number of parameters between the measured and predicted cylinder pressure waveform such as maximum pressure, maximum rate of pressure rise and indicated mean effective pressure. The performance of the network was also evaluated for a number of untrained running conditions that differ both in speed and load from the trained ones. The results for the validation set were comparable to the trained conditions.

  • 521.
    Johnsson, Roger
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sensitivity analysis of transfer function estimation in inverse methods2005Ingår i: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, nr Suppl 1, s. S16-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Summary form only given. A complex sound source consists of several partial sound sources that all contribute to the total sound pressure. A method to separate these partial sound sources into separate time histories is based on inverse filtering of reciprocally measured transfer functions. The transfer functions are measured reciprocally between a number of fictitious monopoles on each partial source and measurement points distributed around the sound source. The method is divided into 5 steps: recording of sound pressure signals, measurement of transfer function, calculation of source strength matrix, calculation of filters and filtering of the recorded sound pressure signals. Correct estimations of the transfer functions are critical for inverse methods to work satisfactory. Normally the transfer functions in this case of studies are calculated as H1 because of the noise contribution to the responses. However, it has been suggested that inverse methods could benefit of using H2 instead. The objective of this investigation is to analyze the effect of selecting either H1 or H2 for the calculation of the transfer functions in case of auralization of separated time histories. For the experiments a complex sound source consisting of two separate cylinder heads with valve covers have been used. Each cylinder head with valve cover was treated as a partial source. The two partial sources were excited with two uncorrelated signals that could be controlled individually. By that, listening tests could be used to verify the authenticity of the separated source signals depending of the transfer functions were estimated as H1 or H2

  • 522.
    Johnsson, Roger
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nykänen, Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A comparison of speech intelligibility in artificial head and Jecklin disc recordings2011Ingår i: 130th Audio Engineering Society convention 2011: London, United Kingdom, 13 - 16 May 2011, Red Hook, NY: Curran Associates, Inc., 2011, Vol. 2, s. 686-694Konferensbidrag (Refereegranskat)
    Abstract [en]

    Binaural recordings are often done using artificial heads but can also be done with a Jecklin disc. In this study an experiment was designed that allowed evaluation of noise and reverberation suppression based on speech intelligibility measurements. Recordings of a voice and disturbing noise were done in a reverberant environment using one artificial head and four Jecklin discs of various sizes. A listening experiment using headphones was conducted to determine the speech intelligibility in the recordings and in a real life situation. It was found that there was no significant difference in the speech intelligibility between the artificial head and Jecklin disc with a diameter of 36 cm.

  • 523.
    Johnsson, Roger
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nykänen, Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Stud noise auralization2013Ingår i: SAE technical paper series, ISSN 0148-7191, Vol. 6, nr 3, s. 1577-1585Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During the winter special winter tires are used to prevent the car from slipping and the grip can be improved by using studded tires. Studded tires are known to cause higher noise levels and noise that is perceived as more annoying than non-studded tires. The objective was to model the interaction between the stud pattern and the stud/tire response (i.e. sound) caused by the excitation of the studs, and to make the result audible. In this study the interior airborne noise caused by the studs was auralized using a combination of recordings, modeling and filtering.The proposed stud auralization model makes it possible to evaluate the influence of the stud pattern and the stud/tire response at any desired speed. The noise caused by the studs is determined by the stud/tire responses when studs hit the pavement, the stud pattern and the speed of the tire. The stud patterns and the stud/tire responses were measured for 5 different studded tires. Auralizations were created for all combinations of stud patterns and responses at two different speeds. A listening test was conducted to assess the annoyance of the stud noise auralizations.From the listening test it was found that no single stud pattern or stud/tire response always performed best. There were large variations between the two auralized speeds. This implies that a stud pattern cannot be developed without taking the response of the tire into account. Auralizations must also be done and evaluated at different speeds.

  • 524.
    Johnsson, Roger
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Odelius, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Methods for road texture estimation using vehicle measurements2012Ingår i: Proceedings ISMA 2012: International Conference on Noise and Vibration Engineering : including USD2012 : Leuven, 17 - 19 September 2010, Leuven: Katholieke Universitat , 2012, s. 1573-1582Konferensbidrag (Refereegranskat)
  • 525. Johnsson, Roger
    et al.
    Odelius, Johan
    Nykänen, Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Self assessment of speech intelligibility listening to binaural recordings2009Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009: INTER-NOISE 2009 ; Ottawa, Canada, 23 - 26 August 2009 / [ed] J. Stuart Bolton, Red Hook, NY: Curran Associates, Inc., 2009, s. 43-51Konferensbidrag (Refereegranskat)
    Abstract [en]

    Our ability to focus on a talker in an environment with several talkers is improved by our binaural hearing. The ability to listen to one talker is improved if the talkers are spatially well separated. A common problem with binaural recordings is front-back confusion, which can make it more difficult to focus on the target talker among several talkers. In this study the ability to localize a talker is compared to the ability to follow a talker in situations with several talkers. In the first part the subjects were asked to localize a talker in the horizontal plane listening to binaural recordings. In the second part of the study the subjects were instructed to assess their ability to follow a target male voice in presence of a masker consisting of two voices (male and female).Target and maskers were presented through separate loudspeakers in various positions. The same listening test was also performed with binaural recordings of the test environment using different artificial heads and in-ear recordings of humans. In both parts the binaural recordings were presented to the subjects through loudspeakers using cross-talk cancellation. Correlation between localization performance and self assessed speech intelligibility was analyzed.

  • 526.
    Johnsson, Roger
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Odelius, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A new test track for automotive squeak and rattle (S&R) detection2014Ingår i: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 80, s. 79-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The perceived quality of interior sounds is of increasing importance in the automotive industry since it is important for the customer perception of vehicle quality. Squeak and rattle (S&R) is a group of intermittent interior noise that reduce the sense of quality dramatically. To identify and solve S&R problems the car manufacturers do both simulations and tests in laboratory of complete vehicles as well as subsystems. As a complement, to laboratory testing and for verification, complete vehicle tests at proving grounds are done. In order to systematically test for vehicle S&R noise at proving grounds there is a need for a new type of test track that in a controlled and repetitive ways excite vehicles at different frequencies. This paper describes such a new test track, called the Frequency Sweep Test Track (FSTT). The test track is based on sweep excitation and improves the precision when detecting and solving S&R issues. Different design considerations such as sweep waveform, frequency range and sweep rate are discussed. The track design is evaluated using a quarter-car model including a tandem ellipsoid tyre model. In a case study a FSTT was built and the excitation of a car was measured. The track excited the expected frequency range and the track operated well in detecting a rattle in the dashboard of an executive production car and at which frequency the rattle occurred.

  • 527. Johnsson, Roger
    et al.
    Tingvall, Bror
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Predicitng interior factory noise with ray-tracing modelling: an example of hardening plant2000Ingår i: Proceedings: Inter.Noise 2000 : August 27 - 30, 2000, Nice, France / [ed] Didier Cassereau, Paris: SFA , 2000, s. 1595-1599Konferensbidrag (Refereegranskat)
  • 528. Johnsson, Roger
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Cylinder pressure reconstruction from vibration and speed measurements on IC engines2004Ingår i: Noise and vibration engineering: proceedings of ISMA 2004 / [ed] P. Sas, Heverlee: Katholieke Univ. Leuven , 2004, s. 965-974Konferensbidrag (Refereegranskat)
    Abstract [en]

    Knowledge of the in-cylinder pressure pulse in IC engines is of main importance in order to fulfill the requirements on low fuel consumption, exhaust emissions and noise. Direct measurements of the in-cylinder pressure are not suitable outside the laboratory environment due to a number of drawbacks. In this paper a combined indirect method for the measurement of the cylinder pressure pulse is developed and verified. The method is based on linear transfer functions between cylinder pressure and engine vibration and crankshaft speed, respectively. The combined method shows better results than achieved by either method separately. The low frequency part of the pressure pulse is reconstructed from crankshaft speed measurements while the high frequency part is reconstructed from vibration measurements. However, there is still a frequency region between the methods where neither method gives a reliable prediction.

  • 529.
    Johnsson, Roger
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ågren, Anders
    Localisation of the TDC-position from crankshaft speed fluctuation measurements2002Ingår i: Proceedings of the Sixth International Conference on Rotor Dynamics, IFT o MM / [ed] E.J. Hahn; R.B. Randall, Sydney: International Federation for the Theory of Machines and Mechanisms , 2002, s. 265-272Konferensbidrag (Refereegranskat)
  • 530. Johnsson, Roger
    et al.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Prediction of points and tendencies of the pressure waveform from crankshaft speed measurements2000Ingår i: Proceedings of ISMA 25, 2000 International Conference on Noise and Vibration Engineering: 2000 September 13 - 15, [Leuven / [ed] P. Sas, Leuven: Katholieke universiteit , 2000, s. 907-12Konferensbidrag (Refereegranskat)
    Abstract [en]

    Direct measurements of the pressure inside the engine have a number of limitations that makes the method expensive and only good for laboratory measurements. Therefore an indirect method to measure the pressure is of main interest. In this study a method based on the crankshaft angular speed fluctuation using neural network has been developed. Two points on the pressure pulse have been reconstructed maximum pressure (Pmax) and start of combustion (SOC). Pmax is predicted with an accuracy of 7.7 MPa and SOC with an accuracy of 1.3 degrees.

  • 531.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Impact of climate on railway operation: a Swedish case study2012Ingår i: IHHA Conference Proceedings 2011, International Heavy Haul Association , 2012Konferensbidrag (Refereegranskat)
  • 532.
    Juntti, Ulla
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Asplund, Matthias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ripke, Burchard
    Lundwall, Björn
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Stenström, Christer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kent, Stephen
    Glebe, Filip
    Nissen, Arne
    AUTOMAIN: D4.1 Improvement analysis for high performance maintenance and modular infrastructure2013Rapport (Övrigt vetenskapligt)
  • 533.
    Juntti, Ulla
    et al.
    Omicold AB.
    Jägare, Veronica
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Enhanced collaboration models in eMaintenance projects2019Ingår i: International Heavy Haul Association Conference June 2019, 2019, s. 925-931Konferensbidrag (Refereegranskat)
  • 534.
    Juntti, Ulla
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson, Lillemor
    Tyréns AB.
    Implementation of eMaintenance concept within the Swedish railway2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    An available, reliable and well-maintained railway is the foundation for competition and market growth. Demands on high standardsfor reliable rail transport, tight turnaround times and high utilization of resources (machines, workshops , staff) makes minimumdisturbance in the system to quickly disrupt the entire process of lost capacity, delays and reduced quality to customers as a result.The Swedish railway composed after deregulation, of several different parties, each one with individually objectives and strategy tomaintain their assets and rolling stock. Although some data are railway system common no greater sharing of operation andmaintenance data exists, which creates the risk of sub-optimisation.Luleå Railway Research Center (JVTC) has since 2005 determinedly conducted research in eMaintenance with the aim of usingdifferent types of condition data to develop decision support using preventive measures to prevent disruption of the railway systemin a cost effective manner. eMaintenance aims to perform and control the maintenance with help of condition data and isinterdisciplinary field based on the information and communication technology ( ICT) to ensure that maintenance is carried out inline with both the customer and the supplier's business goals and intrinsic components in all parts of a system's life cycle.eMaintenance concept has developed progressively over the years and now it is acdcepted o be implemented as a pilot project calledePilot119 in the north part of Sweden on track section 119 between Luleå and Boden. ePilot119 delivers a collaboration platform forthe development needs and requirements from various stakeholders to find solutions that enable and transform the Swedishfragmented rail industry to and an integrated system. ePilot 119 will demonstrate the advantages of working with informationtechnology and data in real time to control railway traffic and service. The approach is based on enhanced collaborationmethodology with a framework project and a central team that is unifying for finding smaller sub-projects for transform ePilot119 toa common natural process for sharing maintenance decision support for the railway. The pilot project aims to demonstrate thathigher availability, enhanced capacity and a cost efficient railway operation can be created using the information that is ineMaintenance lab when used in the right way at the. The goal and strategy and the methodology will be to implemented as a naturalapproach to section 119 and then successively implemented in other sections of track in Sweden.

  • 535.
    Juntti, Ulla
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Stenström, Christer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Asplund, Matthias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Ripke, Burchard
    Lundwall, Björn
    AUTOMAIN: D4.2 Optimised maintenance activities like, grinding, tamping and other maintenance processes2013Rapport (Övrigt vetenskapligt)
  • 536.
    Juntti, Ulla
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Stenström, Christer
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Eriksson, Kristina
    Trafikverket.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Increasing market credibility through continuous vulnerability reduction: A3.5, WP32013Rapport (Övrigt vetenskapligt)
  • 537.
    Juuso, Esko
    et al.
    University of Oulu, Control Engineering, University of Oulu.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Intelligent Real-Time Risk Analysis for Machines and Process Devices2016Ingår i: 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, s. 229-240Konferensbidrag (Refereegranskat)
    Abstract [en]

    Automatic fault detection with condition and stress indices enables reliable condition monitoring to be combined with process control. Useful information on different faults can be obtained by selecting suitable features. Generalised norms can be defined by the order of derivation, the order of the moment and sample time. These norms have the same dimensions as the corresponding signals. The nonlinear scaling used in the linguistic equation approach extends the idea of dimensionless indices to nonlinear systems. The Wöhler curve is represented by a linguistic equation (LE) model. The contribution of the stress is calculated in each sample time, which is taken as a fraction of the cycle time. The cumulative sum of the contributions indicates the degrading of condition and the simulated sums can be used to predict failure time. To avoid high stress situations, the statistical process control (SPC) is extended to nonlinear and non-Gaussian data: the new generalised SPC is suitable for a large set of statistical distributions. It operates without interruptions in short run cases and adapts to the changing process requirements. The scaling functions are updated recursively, which is triggered by a fast increase of the deviation indices. The higher levels, which are rough estimates in the beginning, are gradually refined.

  • 538.
    Jägare, Veronica
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Project: ePilot2015Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Projektet ePilot119 är ett forsknings- och implementeringsprojekt för att utveckla arbetet med järnvägsunderhåll. Målet är att förbättra punktligheten och minimera störningar inom järnvägstrafiken genom att utforma ett beslutsstöd för underhållsåtgärder. Projektet bygger på ett branschsamarbete mellan Järnvägtekniskt centrum, JVTC, vid Luleå tekniska universitet och olika järnvägsföretag och underhållsentreprenörer i Sverige. ePilot119 genomförs på bansträckningen mellan Boden och Luleå, bandel 119. Trafikverket har beställt och är huvudfinansiär av projektet som kommer att pågå under tre år mellan 2013-2016. Målsättningen är att resultaten på sikt ska rullas ut i hela det svenska järnvägssystemet.

  • 539.
    Jägare, Veronica
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Projekt: SIO Agenda Robusta och Tillförlitliga Transportsystem2015Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Agendaprojektet Robusta och tillförlitliga transportsystem syftar till:-Fördubblad transportkapacitet och halverade utsläpp av växthusgaser.-Högre effektivitet i prövning och implementering av nya lösningar.-Effektivitet, hållbarhet och tillväxt i branschen.Projektmålen är:-Att etablera en konstellation av samverkande aktörer från näringslivet, myndigheter och akademi.-Skapa en strategisk innovationsagenda för robusta och tillförlitliga transportsystem.Innovationsområdets potential:-Effektiv ledning och styrning för ökad kapacitet och hållbarhet.-Incitament för samverkan.-Lägre kvalitetsbristkostnader och samhällsekonomiska förluster.-Bättre miljö, minskad resurs- och energiförbrukning.-Export av forskningskompetens, teknologier och tjänster.-Tillämpning i andra system, processer och branscher.Projektet baseras på behovet att transportlösningar är robusta och tillförlitliga, att funktionaliteten i drift vidmakthålls så att driftstörningar förebyggs. Nya lösningar som baseras på diagnostisering och prognostisering av funktionalitet behövs för att möjliggöra detta.För att innovationsområdets potentialer ska kunna realiseras behövs därför samverkan mellan aktörer i olika roller och med olika verksamhetsförutsättningar: SME och stora företag, myndigheter och akademi.I projektet samverkar många aktörer från näringslivet, myndigheter och akademi, vilka tillsammans representerar den samlade kompetens, förmåga och vilja, som behövs för en resultatfokuserad sammanhållen kedja av forskning, innovation, utveckling och implementering.Projektet är öppet för nya aktörer och har korsbefruktande relationer till andra SIO-agendor och programområden.

  • 540.
    Jägare, Veronica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliable railways through collaboration and intelligent innovations2018Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The Swedish railway is composed of several stakeholders, each one with individual objectives and strategies. Although maintenance data used by all, data sharing is not common. Due to this, the lack of data sharing, effects maintenance decision making negatively.

    To support the collaboration necessary for data sharing, decision support tools and enhanced information and communication technologies are needed. Solutions have been successfully developed through research within the eMaintenance field. Research in ICT and maintenance have been conducted in the eMaintenance Lab at Luleå Railway Research Center (JVTC) at Luleå University of Technology, for more than a decade.

    Condition based maintenance is enabled by implementing eMaintenance research results in the ePilot-project, in order to create a collaboration platform; which can transform the Swedish fragmented rail industry to an integrated system, from an organizational and technical point of view. Today, 25 sub-projects has been completed covering solutions e.g. system for predicting degradation of wheel and rail using data from way-side and mobile monitoring equipment and new inspection techniques.

    The paper aims to describe some of the key factors that might enable or hinder the collaboration, sharing of data and implementation of good results, jointly creating the best prerequisites for the operation and maintenance of the railway system.

    The goal of the project is to improve punctuality and minimize disruption in rail services. The project is an industry collaboration between JVTC, the Swedish Transport Administration, railway actors and innovators in Sweden.

  • 541.
    Jägare, Veronica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Juntti, Ulla
    Omicold AB.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Governance of digital data sharing in a cross-organisational railway maintenance context2019Ingår i: Proceedings of the 5th International Workshop and Congress on eMaintenance: eMaintenance: Trends in Technologies & methodologies, challenges, possibilites and applications / [ed] Arranz, Miguel Castano, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The purpose of this paper is to study and explore the essential aspects of data governance in eMaintenance that need to be considered such as data sharing and data ownership in a cross-organisational railway maintenance context. Furthermore, the paper develops and provides an approach to strategies and guidelines, which can be used to govern digital data sharing.

    To fulfil this purpose, case studies of several projects where sharing of data between stakeholders in order to develop maintenance decision support, was selected as a research strategy and supported by a literature study. Empirical data were collected through interviews, workshops, document studies, and observations. An approach was developed and validated using a case study.

    The proposed approach supports the understanding and establishing strategies and guidelines for data governance in a cross-organisational railway context. This can be considered as one of the enablers for information logistics for maintenance purposes where the approach can be used as a support tool in order to facilitate the development of maintenance decision support within the railway industry.

  • 542.
    Jägare, Veronica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Implementation of eMaintenance concept on the Iron Ore Line in Sweden2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Swedish railway is after deregulation composed, of several different stakeholders, each one with individual objectives and strategies to maintain their assets and rolling stock. Although some maintenance data are common between the stakeholders, no greater sharing of these data exists. The insufficient data availability impacts the effectiveness in maintenance decision making.The Luleå Railway Research Center (JVTC) has in more than a decade conducted research in eMaintenance. One of the objectives with eMaintenance research is to develop maintenance decision support tools through enhanced use of information and communication technology for data analytics from various data sources. These tools can also be used to enable condition based maintenance to minimize disruptions and optimise the maintenance cost in a railway system. Another objective this research is to discover how to offer operators, infrastructure managers and system integrators access to central computerised data to support decision making within operation and maintenance.eMaintenance solutions for railway are now being implemented in a pilot project called ePilot119 in the northern part of Sweden on track section 119 between Luleå and Boden. ePilot119 delivers a collaborative platform aimed to enable the development of eMaintenance solutions based on the needs and requirements from various stakeholders. These solutions are expected to enable and transform the Swedish fragmented rail industry to an integrated system, both from an organizational and technical point of view. Some of the objectives are to enhance the sharing of data, developing decision support, define the information and communication technology (ICT) infrastructure and transform ePilot119 to a common natural process for sharing maintenance decision support for the railway.However, implementing eMaintenance solutions to support effective and efficient maintenance decision-making related to a complex technical system (i.e. railway) and with a large number of heterogeneous stakeholders is challenging, and requires appropriate tools (e.g. framework, approaches, methodologies, and technologies).Hence, this paper aims to identify some of the significant factors which need to be considered in order to develop an appropriate implementation process and collaboration platform, which aim to facilitate maintenance decision-making through eMaintenance solutions. By identifying these factors that might hinder the execution of the project and implementation of good results, there is a possibility to jointly create the best prerequisites for the operation and maintenance of the railway system.

  • 543.
    Jägare, Veronica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Juntti, Ulla
    Omicold AB.
    Söderholm, Peter
    Trafikverket.
    A framework for testbed concept in railway2019Ingår i: PROCEEDINGS: International Heavy Haul Association Conference June 2019, 2019, s. 986-Konferensbidrag (Refereegranskat)
    Abstract [en]

    One major prerequisite for an effective implementation and innovation process is the enablement and provision of a collaborative environment. A common area for multi-organisational collaboration together with a technology platform, enabling data sharing and Big Data Analytics, has been developed called ‘Testbed Railway’ with a corresponding framework ‘Railway 4.0’. Testbed Railway can be used to strengthen the railway industry's adaptability and competitiveness by developing and providing a testbed for research and innovation in the rail industry, nationally and internationally.

  • 544.
    Jägare, Veronica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Söderholm, Peter
    Trafikverket.
    Larsson-Kråik, Per-Olof
    Trafikverket.
    Juntti, Ulla
    Omicold AB.
    Change management in digitalised operation and maintenance of railway2019Ingår i: PROCEEDINGS: International Heavy Haul Association Conference June 2019, 2019, s. 904-911Konferensbidrag (Refereegranskat)
    Abstract [en]

    Globally, railway is experiencing a major technology transformation (or paradigm shift), triggered by the enhanced utilisation of digital technology. This technological transformation affects not only the technical systems, i.e. railway infrastructure and rolling stock, but also regulations, organisations, processes,and individuals. Hence, hardware, software, but also liveware (i.e. humans) are affected. Today, the digitalisation of railway is characterised by digital services. There are also a range of challenges, e.g. data acquisition,transformation, modelling, processing, visualisation, safety, security, quality, and information assurance. To deal with these challenges, the railway industry needs to define strategies, which enable a smooth transformation of the existing configuration to a digitalised system. Digital railway requires a holistic change management approach based on system-of-systems thinking and a set of appropriate technologies and methodologies. The railway digitalisation strategy should be based on systematic risk management that address aspects of, e.g., information security, traffic safety and project risk. In addition, managing changes for a digitalised railway effectively and efficiently also requires a framework for aspects such as needs finding, requirement identification, and impact of changes for individual, teams and organisation. In this work a major case studywithin the ePilot, has been performed in context of the operation and maintenance processes of the Swedish railway. Therefore, this paper aims to propose a framework for implementing innovations and driving change in a digitalised railway.

  • 545.
    Jönsson, Jens
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Arasteh Khouy, Iman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Measurement of vertical geometry variations in railway turnouts exposed to different operating conditions2016Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 230, nr 2, s. 486-501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Turnouts are critical units in a railway system; they perform the switching procedure that allows trains to change between routes. Monitoring the track geometry of a turnout is necessary for maintenance planning and design optimisation. Monitoring is usually done by track recording cars, however, to isolate the ageing and dynamic behaviour of the track it is also necessary to study the unstressed track geometry of the turnouts. Such measurements can be used to develop degradation models to optimise maintenance and design, thereby increasing availability and reducing life cycle cost. This paper introduces a new method to measure the vertical position of the track geometry over time during non-operational conditions (unstressed) to show track degradation. The new method includes a smart system that uses relative measurement reference points to create a better accuracy and lower costs compared with fixed reference points. It evaluates various types of measurement equipment and uses levelling equipment to measure the unstressed vertical geometry of 13 turnouts located on Swedish railway lines, with three follow-up measurements over a year and a half. The turnouts were categorised into four groups: based on their accumulated capacity in million gross tonnes (MGT) and whether they were on a straight or curved main track. Surprisingly, the first three measurements showed the geometry of turnouts on the straight main track to have a vertical elevation tendency towards the mid-section, whereas the turnouts on the curved main track had a general vertical downwards bend tendency towards the mid-section. The results also showed that a higher capacity in MGT has a greater influence on track geometry changes over time.

  • 546.
    Jönsson, P.
    et al.
    Luleå tekniska universitet.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Prediction of vehicle discomfort from transient vibrations2005Ingår i: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 282, nr 3-5, s. 1043-1064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Vehicle manufacturers are continuously seeking to improve vibration comfort. In this paper, subjective responses from transient vibrations in a forklift were analyzed on the basis of ISO 2631-1 and a number of additional variables. The objectives were to define: the effect of different operating conditions and appropriate background variables of subjects on perceived motions; the development of model that describes perceived discomfort as a function of measured vibrations; and important frequencies for prediction of vibration discomfort. The experiment was based on 12 different operating conditions defined by the variables: vehicle speed, obstacle height and load conditions. Eleven professional drivers participated and their responses of overall discomfort were defined by a vector sum of three perceived motions: shaking, for-aft and up-down motions. The evaluation method, maximum transient vibration value as defined in ISO 2631-1 was found to be adequate in predicting vibration discomfort during a four second transient vibration exposure. By analysis of narrow frequency band spectra of vibrations several explanations for the test results are discussed. The best results were obtained using a prediction model based on accelerations in -octave bands of pitch vibrations.

  • 547. Kajko-Mattsson, Mira
    et al.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Mirijamdotter, Anita
    Essential components of emaintenance2011Ingår i: International Journal of Pedagogy, Innovation and New Technologies, ISSN 0973-1318, E-ISSN 2392-0092, Vol. 7, nr 6, s. 555-571Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many intellectual, societal, business and technological forces are continuously pushing forward the frontiers of science. When combined, they provide an umbrella for generating new fields and exploring new grounds. One such a new field is eMaintenance. eMaintenance addresses new needs and provides various benefits in form of increased availability, reduced lifecycle cost and increased customer value. However, it suffers from lack of a commonly defined basis supporting the existence of eMaintenance and determining the essential components inherent in the eMaintenance domain. In this paper, we suggest an initial set of components that serve as the groundwork of the eMaintenance universe. The set outlines ten initial components. These are Definition, Business, Organization, Product, Service, Methodology, Technology, Information, Customer, and Education and Training. The paper also suggests a definition of eMaintenance, places eMaintenance in the context of other eDomains, and elicits eMaintenance intellectual opportunities and challenges to be met by both the academia and industry.

  • 548.
    Kajko-Mattsson, Mira
    et al.
    Stockholm University.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Mirijamdotter, Anita
    Linnéuniversitetet.
    Fundamentals of the eMaintenance concept2010Ingår i: Proceedings of the 1st international workshop and congress on eMaintenance, Luleå tekniska universitet, 2010, s. 147-154Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many intellectual, societal, business and technological forces are continuously pushing forward the frontiers of science. When being combined effectively, they may provide an umbrella for generating new fields and exploring new grounds. One such emerging field is eMaintenance. It is based on the fields from operation & maintenance engineering, software engineering, information systems, business management, and a myriad of strongly varying fields related to the application domains of eMaintenance. As a novel field, eMaintenance addresses new needs and provides various benefits in form of increased availability, reduced lifecycle cost and increased customer-value. On the other hand, being in a continuous flux, it suffers from many infant illnesses in form of lack of or fuzzy definitions and theoretical foundations. This paper explores the domain of eMaintenance. In striving toward that end, it defines the eMaintenance concept by identifying its essential constituents and characteristics, mapping out its application domains and by eliciting its intellectual opportunities and challenges. Finally, the paper reasons about the future of eMaintenance as an emerging field and identifies research questions that may serve as the impetus for defining future research strategies. Last but not least, it lists challenges to be met by the organizations transferring to eMainteannce and advocates to the eMaintenance community to further elaborate and improve the eMaintenance concept.

  • 549.
    Kans, Mirka
    et al.
    Linnaeus University.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Thaduri, Adithya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Maintenance 4.0 in railway transportation industry2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    Transportation systems are complex with respect to technology and operations with involvement in a wide range of human actors, organizations and technical solutions. For the operations and control of such complex environments, a viable solution is to apply intelligent computerized systems, such as computerized traffic control systems for coordinating airline transportation, or advanced monitoring and diagnostic systems in vehicles. Moreover, transportation assets cannot compromise the safety of the passengers by applying operation and maintenance activities. Indeed safety becomes a more difficult goal to achieve using traditional maintenance strategies and computerized solutions come into the picture as the only option to deal with complex systems interacting among them trying to balance the growth in technical complexity together with stable and acceptable dependability indexes. Industry 4.0 is a term that describes the fourth generation of industrial activity which is enabled by smart systems and Internet-based solutions. Two of the characteristic features of Industry 4.0 are computerization by utilizing cyber-physical systems and intelligent factories that are based on the concept of "internet of things". Maintenance is one of the application areas, referred to as maintenance 4.0, in form of self-learning and smart systems that predicts failure, makes diagnosis and triggers maintenance by making use of “internet of things”. This paper discusses the possibilities that lie within applying the maintenance 4.0 concept in the railway transportation industry. This paper also discusses the positive effects on technology; organisation and operations from a systems perspective.

  • 550.
    Kans, Mirka
    et al.
    Linnaeus University.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Thaduri, Adithya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Maintenance 4.0 in Railway Transportation Industry2016Ingår i: Proceedings of the 10th World Congress on Engineering Asset Management (WCEAM 2015) / [ed] Kari T. Koskinen; Helena Kortelainen; Jussi Aaltonen; Teuvo Uusitalo; Kari Komonen; Joseph Mathew; Jouko Laitinen, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 317-331Konferensbidrag (Refereegranskat)
    Abstract [en]

    Transportation systems are complex with respect to technology and operations with involvement in a wide range of human actors, organisations and technical solutions. For the operations and control of such complex environments, a viable solution is to apply intelligent computerised systems, such as computerised traffic control systems for coordinating airline transportation, or advanced monitoring and diagnostic systems in vehicles. Moreover, transportation assets cannot compromise the safety of the passengers by applying operation and maintenance activities. Indeed safety becomes a more difficult goal to achieve using traditional maintenance strategies and computerised solutions come into the picture as the only option to deal with complex systems interacting among them trying to balance the growth in technical complexity together with stable and acceptable dependability indexes. Industry 4.0 is a term that describes the fourth generation of industrial activity which is enabled by smart systems and Internet-based solutions. Two of the characteristic features of Industry 4.0 are computerization by utilising cyber-physical systems and intelligent factories that are based on the concept of “internet of things”. Maintenance is one of the application areas, referred to as maintenance 4.0, in form of self-learning and smart systems that predicts failure, makes diagnosis and triggers maintenance by making use of “internet of things”. This paper discusses the possibilities that lie within applying the maintenance 4.0 concept in the railway transportation industry and the positive effects on technology, organisation and operations from a systems perspective.

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