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  • 1.
    Algers, Björn
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Stereo Camera Calibration Accuracy in Real-time Car Angles Estimation for Vision Driver Assistance and Autonomous Driving2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The automotive safety company Veoneer are producers of high end driver visual assistance systems, but the knowledge about the absolute accuracy of their dynamic calibration algorithms that estimate the vehicle’s orientation is limited.

    In this thesis, a novel measurement system is proposed to be used in gathering reference data of a vehicle’s orientation as it is in motion, more specifically the pitch and roll angle of the vehicle. Focus has been to estimate how the uncertainty of the measurement system is affected by errors introduced during its construction, and to evaluate its potential in being a viable tool in gathering reference data for algorithm performance evaluation.

    The system consisted of three laser distance sensors mounted on the body of the vehicle, and a range of data acquisition sequences with different perturbations were performed by driving along a stretch of road in Linköping with weights loaded in the vehicle. The reference data were compared to camera system data where the bias of the calculated angles were estimated, along with the dynamic behaviour of the camera system algorithms. The experimental results showed that the accuracy of the system exceeded 0.1 degrees for both pitch and roll, but no conclusions about the bias of the algorithms could be drawn as there were systematic errors present in the measurements.

    Fulltekst (pdf)
    fulltext
  • 2.
    Antona-Makoshi, Jacobo
    et al.
    Japan Automobile Research Insitute, Ibaraki, 2530 Karima, Tsukuba, Japan.
    Mikami, Koji
    Japan Automobile Research Insitute, Ibaraki, 2530 Karima, Tsukuba, Japan.
    Lindquist, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Davidsson, Johan
    Chalmers University of Technology, Gothenburg, Sweden.
    Analysis of Traumatic Brain Injuries Sustained by Occupants in Japanese Brand Car Crashes in the US2018Inngår i: International Journal of Automotive Engineering, E-ISSN 2185-0992, Vol. 9, nr 3, s. 145-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study estimates, by means of an analysis of accident data from the US, the incidence and risk of car crash related traumatic brain injuries for occupants in Japanese brand cars. The study incorporated crash type, crash severity, car model year, belt use and the victim's age and sex. Concussion risk was the highest among all brain injury categories for all crash types and severities; females were at higher risks than males. When concussions were excluded, Subdural Haemorrhages, Intracranial Haemorrhages and Sub-Arachnoid Haemorrhages comprised the most frequent injury categories. Elderly occupants were at considerably higher risks than non-elderly for these bleeding injuries

    Fulltekst (pdf)
    fulltext
  • 3.
    Berglund, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Application of an alternative frequency response technique to the durability assessment of engine components2011Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Engine components are exposed to vibrations which may lead to fatigue damage. Accurate dynamic simulations are necessary especially during the development process, in order to find a satisfactory component.

    Currently Scania uses a standard method for dynamic calculations that is based on a frequency response approach. A measured or calculated excitation yields a certain response through the transfer function of the system. The transfer function is obtained through an eigenfrequency calculation and an experience-based estimate of the modal damping. An obvious drawback of this method is that the estimated modal damping strongly affects the calculated response of the system.

    In this thesis, the method outlined above is compared to an alternative, so-called, inverse method in which the excitation of the system is calculated using a measured response. The advantage is that the modal damping does not affect the result directly since the excitation has been adjusted according to the response. As a demonstration object a charge air pipe and its bracket are used. Acceleration response data is collected from an engine vibration measurement.

    The calculated safety factor of the demonstration object is reasonable for both the standard method and the inverse method. An estimate of the quality of the model is obtained for the inverse method through statistical measures, which is not the case for the standard method. The excitation for the inverse method is adjusted to the estimated modal damping which is a major advantage since damping is notoriously difficult to quantify in engineering practice. The inverse method has proven to be a useful simulation method for calculations when a prototype of the engine component of interest already exists.

    Fulltekst (pdf)
    FULLTEXT01
  • 4.
    Bley, Jessica
    et al.
    AD Safe Experience, Volvo Cars, Chalmers University of Technology, Gothenburg, Sweden.
    Eriksson, Alexander
    AD Safe Experience, Volvo Cars, Gothenburg, Sweden.
    Johansson, Lisa
    AD Safe Experience, Volvo Cars, Chalmers University of Technology, Gothenburg, Sweden.
    Wiberg, Mikael
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för informatik. Chalmers University of Technology, Gothenburg, Sweden.
    Design friction in autonomous drive: exploring transitions between autonomous and manual drive in non-urgent situations2023Inngår i: Personal and Ubiquitous Computing, ISSN 1617-4909, E-ISSN 1617-4917, Vol. 27, nr 6, s. 2291-2305Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the ongoing turn to automation, the growing trend towards the design of conditionally and highly automated vehicles (C/HAV) is evident. In a CAV, the driver no longer needs to partake in the driving. However, the vehicle might send a takeover request (TOR) when the CAV's system reaches its operational boundaries, i.e. a call for a transition from autonomous to manual drive. Previous research on TORs has focused on the context of urgent situations, e.g. hazards and unpredictable events. Furthermore, it has been noted that drivers’ situation awareness (SA) deteriorates after being in autonomous drive. However, less is known about TORs in non-urgent situations. Motivated by this need, the study explores how design friction can serve as a guiding concept for transferring control between autonomous and manual drive in non-urgent situations to increase situation awareness. Design friction is defined as elements of interactions that steer attention and guides the driver to take informed decisions. The work resulted in prototypes that leveraged design friction as part of a takeover sequence. The proposed design was empirically evaluated in a fixed-base medium-fidelity driving simulator. The results indicated that the level of friction might have been too extensive, as some annoyance was expressed. However, participants claimed to feel calm and aware of their surroundings at the moment of regaining control of the vehicle. This suggests that design friction is a promising tool for guiding concept design to enhance transitions from autonomous to manual drive.

    Fulltekst (pdf)
    fulltext
  • 5. Chen, Yuqing
    et al.
    Kang, Yuqiong
    Zhao, Yun
    Wang, Li
    Liu, Jilei
    Li, Yanxi
    Liang, Zheng
    He, Xiangming
    Li, Xing
    Tavajohi Hassan Kiadeh, Naser
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Li, Baohua
    A review of lithium-ion battery safety concerns: the issues, strategies, and testing standards2021Inngår i: Journal of Energy Chemistry, ISSN 2095-4956, E-ISSN 2096-885X, Vol. 59, s. 83-99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efficient and reliable energy storage systems are crucial for our modern society. Lithium-ion batteries (LIBs) with excellent performance are widely used in portable electronics and electric vehicles (EVs), but frequent fires and explosions limit their further and more widespread applications. This review summarizes aspects of LIB safety and discusses the related issues, strategies, and testing standards. Specifically, it begins with a brief introduction to LIB working principles and cell structures, and then provides an overview of the notorious thermal runaway, with an emphasis on the effects of mechanical, electrical, and thermal abuse. The following sections examine strategies for improving cell safety, including approaches through cell chemistry, cooling, and balancing, afterwards describing current safety standards and corresponding tests. The review concludes with insights into potential future developments and the prospects for safer LIBs.

    Fulltekst (pdf)
    fulltext
  • 6.
    Classon, Andreas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Enkelt utbytbara instegs delar: En ny lösning för en instegsmodul till lastbil med högmognadsgrad. Forskning har fokuserats på ergonomi och materialval.2014Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The task was to deliver a solution that could be implemented in today’s production of the FH truck. To make the project successful it was most important that the end result had a high maturity level. For that reason an analysis of ergonomic, laws and regulations, and possible materials where conducted. To show that this project is profitable and can be realized a ruff cost estimated of material and tools is added to the research. By doing smart material choices and not changing more than necessary existing part or for that matter add more parts the outcome is more economic then if the whole ingress module is change. Catia V.5 is used as a construction program and the built-in FEA module (Finite Element Analysis) to check the strength of the construction. This is done to see that the product withstands the applied force from a person. The project result is a updated version on the ingress module where the footboard is easily change without having to remove any parts of the module. What has happened is that the footstep is divided in to two parts, one frame that’s mounted on the chassi on the truck and one footboard that is mounted on the frame. That meant that the plastic cover hade to be change as well as the footsteps. The assembly line for this new ingress module is almost identical to what it is today besides the footboard that’s added. The weight has been reduced with 15 % without doing any bigger changes on the assembly line or adding cost (if not counting for new tools). 

    Fulltekst (pdf)
    easy to replace footstep parts
  • 7.
    Davidsson, Johan
    et al.
    Department of Mechanical Engineering, Chalmers University of Technology, Sweden.
    Carroll, Jolyon
    Department of Biomechanics, Transport Research Laboratory, United Kingdom.
    Hynd, David
    Department of Biomechanics, Transport Research Laboratory, United Kingdom.
    Lecuyer, Erwan
    LAB PSA Peugeot Citroën Renault, France.
    Song, Eric
    LAB PSA Peugeot Citroën Renault, France.
    Trosseille, Xavier
    LAB PSA Peugeot Citroën Renault, France.
    Eggers, Andre
    BAST, Germany.
    Sunnevång, Cecilia
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Praxl, Norbert
    Partnership for Dummy Technology and Biomechanics, Germany.
    Martinez, Luis
    Biomechanics Unit, INSIA, Spain.
    Lemmen, Paul
    Humanetics Europe, Netherlands.
    Been, Bernard
    Humanetics Europe, Netherlands.
    Development of injury risk functions for use with the THORAX Demonstrator: an updated THOR2014Inngår i: 2014 IRCOBI Conference Proceedings, International Research Council on the Biomechanics of Injury , 2014, s. 359-376Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The thorax-shoulder complex of the THOR dummy was updated in the EU-project THORAX. The new dummy, the THORAX demonstrator, was evaluated in several biomechanical test conditions. In this study, selected data from these tests and injury information from the original tests with Post Mortem Human Subjects were used to develop injury risk functions in accordance with the guidelines defined within ISO/TC22/SC12/WG6. This included the use of survival analysis, distribution and quality assessments. The results include draft injury risk functions for three THORAX injury criteria intended for frontal and oblique loading. The maximum peak deflection measurement (Dmax) and a new differential deflection criterion (DcTHOR) were found to have a good injury risk quality index. Furthermore, a new local strain-based concept, denoted Number of Fractured Ribs (NFR), appeared to be a potentially useful injury criterion as by its nature it is less sensitive to restraint conditions than deflection measures although it had a lower quality index compared with the displacement-based criteria.

  • 8. De Alcantara Dias, Bruno Martin
    et al.
    Maria Lagana, Armando Antonio
    Justo, Joao Francisco
    Yoshioka, Leopoldo Rideki
    Dias Santos, Max Mauro
    Gu, Zonghua
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Model-based development of an engine control module for a spark ignition engine2018Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 6, s. 53638-53649Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A Spark ignition (SI) engine is a complex, multi-domain component of the vehicle powertrain system. The engine control module (ECM) for an SI engine must achieve both high performance and good fuel efficiency. In this paper, we present a model-based development methodology for an open architecture ECM, addressing the entire development lifecycle including a control algorithm design, parameter calibration, hardware/software implementation, and verification/validation of the final system, both with bench tests on a dynamometer and in a real vehicle on the road. The ECM is able to achieve similar performance as the original proprietary ECM provided by the original equipment manufacturer. Its flexible and modular design enables easy extensibility with new control algorithms, and development of new engine types.

  • 9.
    Edlund, Jeanette
    et al.
    Sveriges lantbruksuniversitet.
    Servin, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Keramati, Ehsan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    A long-tracked bogie design for forestry machines on soft and rough terrain2013Inngår i: Journal of terramechanics, ISSN 0022-4898, E-ISSN 1879-1204, Vol. 50, nr 2, s. 73-83Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new design for a tracked forestry machine bogie (long track bogie; LTB) on soft and rough terrain is investigated using nonsmooth multibody dynamics simulation. The new bogie has a big wheel that is connected to and aligned with the chassis main axis. A bogie frame is mounted on the wheel axis but left to rotate freely up to a maximum angle and smaller wheels that also rotate freely are mounted on the frame legs with axes plane parallel to the driving wheel. The wheels are covered by a single conventional forestry machine metal track. The new bogie is shown to have higher mobility and cause less ground damage than a conventional tracked bogie but requires larger torque to create the same traction force as a conventional bogie. The new bogie also gives less acceleration when passing obstacles than the conventional bogie. Additionally, due to the shape and size of the new bogie concept, it can pass wider ditches.

  • 10.
    Edlund, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Designhögskolan vid Umeå universitet.
    Jacques: Your underwater camera companion2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    300 million pictures are uploaded everyday on Facebook alone. We live in a society where photography, filming and self-documentation are a natural part of our lives. But how does it inflict on our experiences when we always are considering camera angles, filters and compositions? We might very well ruin the experiences we so badly want to save.

    Scuba diving is a special experience. We enter a world with another space of movement, surroundings and animal life. An experience that can only be experienced for a limited time. An adventure one want to remember, save and share. But what implications does it have on ones experience if one also have to focus on documenting it?

    JACQUES is a product that enables the diver´s to document their dive as a memory to re-experience later and share with others while still leaving them fully immersed in their diving experience. With relatively simple technology such as sonar and video object recognition Jacques can film the diver´s underwater adventure and adept to their behavior without the diver even noticing it. And by being focused on the actual dive one also becomes a better and safer diver.

    Fulltekst (pdf)
    Jacques
  • 11.
    Fredriksson, Rikard
    et al.
    Autoliv Research, Vårgårda, Sweden.
    Bylund, Per-Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Öman, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Fatal vehicle-to-bicyclist crashes in Sweden - An in-depth study of injuries and vehicle sources2012Inngår i: Annals of Advances in Automotive Medicine, 2012, s. 25-30Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Designing effective vehicle-based countermeasures for vulnerable road users demands an understanding of the relationship between injury and injury source. The aim of this study was to explore this association for bicyclists in fatal real-life-crashes. All fatal crashes in Sweden where a bicyclist was killed when hit by the front of a passenger car between 2002 and 2008 were studied in detail using on-scene data. An analysis was performed to determine the body region containing the injury causing death, and the point of the car accountable for the fatal injury. These crashes were then compared to a previous study with the same selection criteria for vehicle-to-pedestrian fatal crashes.

    A combined analysis revealed that the dominating injury mechanism was head/neck injury from the windshield area. The most frequent injurious windshield parts were structural; the frame and lower parts of the glass area with instrument panel situated within the head's line of motion. This study indicates that bicyclists' injury sources were located more rearwardly on the car (e.g. windshield relative to hood), in comparison to injury sources in fatal vehicle-to- pedestrian crashes.

    If countermeasures to prevent fatal bicyclist injury in vehicle impacts were to be concentrated on mitigating head and thorax impact to the structural parts of the windshield, a dominant share of fatal bicyclist crashes could be prevented. This study shows that pedestrian countermeasures also have a potential for reducing injury in bicyclist crashes, but indicating that these countermeasures should be extended to address higher areas of the windshield. 

  • 12.
    Hansson, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Transient road simulation of the cooling system in heavy-duty trucks using KULI2016Independent thesis Advanced level (degree of Master (Two Years)), 300 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 13. Hansson, Sven Ove
    et al.
    Belin, Matts-Åke
    Lundgren, Björn
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier. The Institute for Futures Studies, Stockholm, Sweden; Department of Philosophy, Stockholm University, Stockholm, Sweden.
    Self-Driving Vehicles: an Ethical Overview2021Inngår i: Philosophy & Technology, ISSN 2210-5433, E-ISSN 2210-5441, Vol. 34, s. 1383-1408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The introduction of self-driving vehicles gives rise to a large number of ethical issues that go beyond the common, extremely narrow, focus on improbable dilemma-like scenarios. This article provides a broad overview of realistic ethical issues related to self-driving vehicles. Some of the major topics covered are as follows: Strong opinions for and against driverless cars may give rise to severe social and political conflicts. A low tolerance for accidents caused by driverless vehicles may delay the introduction of driverless systems that would substantially reduce the risks. Trade-offs will arise between safety and other requirement on the road traffic system. Over-reliance on the swift collision-avoiding reactions of self-driving vehicles can induce people to take dangerous actions, such as stepping out in front of a car, relying on its fast braking. Children travelling alone can violate safety instructions such as the use of seatbelts. Digital information about routes and destinations can be used to convey commercial and political messages to car users. If fast passage can be bought, then socio-economic segregation of road traffic may result. Terrorists and other criminals can hack into a vehicle and make it crash. They can also use self-driving vehicles for instance to carry bombs to their designed places of detonation or to wreak havoc on a country’s road system.

    Fulltekst (pdf)
    fulltext
  • 14. Iraeus, Johan
    et al.
    Lindquist, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Analysis of minimum pulse shape information needed for accurate chest injury prediction in real life frontal crashes2021Inngår i: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 26, nr 6, s. 684-691Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The relationship between crash pulse shape and injury risk has been studied primarily with laboratory studies, but these are not necessarily representative of most real-life crashes. For the past decade, pulse information from real-life crashes has been available through event data recorders. The aim of this study is to evaluate how crash pulses from event data recorders can be parameterized with as few parameters as possible without losing the ability to accurately predict occupant injury. Pulses from 122 NASS/CDS cases with a delta velocity over 40 km/h were parameterized using eigenvector analysis. Six different pulses were created for each of these cases, including the original pulse and five approximations with gradually more pulse information. Using a finite-element sled model with the detailed THUMS human body model, the risk of chest injury was evaluated for each pulse version in each case. By comparing the results from each pulse approximation to the original pulse, the change in chest injury could be evaluated as a function of pulse approximation for each case. Using linear regression to analyse the chest injury error results it was found that a pulse with as few as four parameters-delta velocity, duration, and two shape parameters-can sufficiently describe the pulse shape from a chest injury point of view.

    Fulltekst (pdf)
    fulltext
  • 15.
    Johan, Nordberg
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Kylsystem för transmissionsdelar integrerat i fordonsstruktur2020Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    På uppdrag av BAE Systems Hägglunds i Örnsköldsvik har möjligheterna till att integrera oljekylare, reservoarer och pumpar i strukturen på ett av deras fordon studerats. En oljekyld transmission och en oljekyld våtlamellbroms kräver kylning och smörjning för att möta de höga krav som ställs på fordonet. Idag är systemet komplext med ett stort antal komponenter och exponerade, känsliga oljeledningar som löper längs fordonets utsida. Genom att integrera dessa system i fordonsstrukturen kan systemet förenklas avsevärt och känsliga komponenter sitta säkert bakom plåt. De kvalitéer systemet skulle ha kartlades genom att upprätta en kravspecifikation. Beräkningar på värmeutveckling vid körning i hög fart och upprepade inbromsningar gjordes. Med detta som bas utvecklades tre möjliga koncept. De bästa delarna från koncepten sammanställdes till ett slutgiltigt koncept som beskrivs och diskuteras.Konceptet som tagits fram har potential för vidareutveckling och realisering. Föreliggande arbete är att betrakta som ett första steg i en lång serie konstruktionssteg, beräkningar, simuleringar och tester. Mycket arbete finns att göra innan systemet kan tas i produktion.

  • 16.
    Johansson, Albin
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Lorenz, Krzysztof
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Implementering av hybriddrivlina i BAE Systems bandvagn2021Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    This work has been carried out at BAE Systems in Örnsköldsvik. The background to the work is that BAE Systems is developing a hybrid electric driveline for the BvS10 tracked vehicle (Sirius project), but lacks the necessary drawings, i.e. a 3D model, for the construction of this vehicle. The purpose of the work was to create data regarding the 3D model, weight, center of gravity and inner volume analyzes for the future construction of this hybrid-driven tracked vehicle.

    A 3D model of a complete BVs10 front cab with hybrid drivetrain was created by removing all systems that belonged to the old driveline in the original 3D model and then replacing them with new drivetrain components for a hybrid-driven tracked vehicle. In order for the components that belonged to the hybrid driveline to fit and meet the weight and volume requirements, large relocations of components inside the vehicle had to be carried out. When comparing the weight and volume between the original platform and the new hybrid-driven platform, all data were calculated based on what happens to the vehicles center of gravity in the horizontal and vertical axis with regard to the vehicles direction of travel.

    Two concepts were developed in this work regarding service weight, center of gravity and internal volume. Notwithstanding the concept, the parameters are improved compared to the original construction, which shows that the Sirius concept improves the properties of the tracked vehicle with regard to the technical requirements placed on the project. The requirements are seen as met as the results presented in this report show that the Sirius concept improves the vehicle`s characteristics regarding weight, center of gravity and volume, which means that this work is seen as successful. The result of this report is something that BAE will use in future development.

    Fulltekst (pdf)
    Rapport
  • 17.
    Jonsson, Bertil
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Krafft, Maria
    Umeå universitet. Folksam research.
    Kullgren, Anders
    Folksam Research; Chalmers University of Technology, Sweden.
    Development of Whiplash associated Disorders for adult and child occupants in cars launched since the 1980s in different impact directions2011Inngår i: 2011 IRCOBI Conference Proceedings, International Research Council on the Biomechanics of Injury , 2011, s. 62-72Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Studies have shown that crashworthiness of cars addressing fatal and serious injuries has generally improved over time. However, the development regarding injuries leading to medical impairment has not been shown to the same extent. The objective was to investigate the development of Whiplash associated Disorders (WAD) leading to long-term consequences for adult front seat occupants and for children 0-12 years of age in cars introduced at different year intervals and in different impact directions separated for gender. Long-term consequences were defined as occupants with WAD symptoms at least one month and those resulting in medical impairment. The developments were studied for cars divided into intervals according to year of introduction and for frontal, side and rear-end impacts. All adult occupants (35 611) and 76% of all children (973) reporting WAD between 1998 and 2008 were selected. Approximately 2% of the children reporting initial symptoms sustained medical impairment. The corresponding figure for adult occupants was approximately 10%. Between the introduction years 1980-84 and 2000-04 the proportions of adult occupants with medical impairment dropped by approximately 70% (both males and females) in frontal and rear-end crashes, while the reduction in lateral impacts appears to be somewhat lower. For children there is a tendency that the proportion of WAD increases in newer models in frontal collisions. The result indicates that protecting children facing forward deserves more attention from the automotive industry and governmental bodies.

  • 18.
    Kerwien, Joakim
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Vibrationsdämpare för frontlucka: Koncept för vibrationsdämpare med justering2017Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Sammanfattning

     

    På lastbilsmodellerna FH och FM från Volvo, finns det vibrationsdämpare mellan karossen och frontluckan. Dessa dämpar rörelse vid en hård stängning av luckan, förhindrar att luckan ock dörren kolliderar. 

    De nuvarande vibrationsdämparna går inte att justera på något vis, detta vill Volvo kunna göra, för att lättare kunna justera in frontluckans position mot dörren och få en bra inpassning som ger ett bra kvalitetsintryck för kunden. Flera koncept ska tas fram för att sedan jämföras med varandra i en beslutsmatris.

    Arbetet utförs på Volvo GTT, konstruktionsavdelning av Volvo GTO, i Umeå.

     

    Viktiga avgränsningar:

    • Endast framtagning av koncept, inte någon produktion av delarna.
    • Inga hållfasthetsberäkningar av mig eller FEM-analys.
    • Använda mig av programvaran CATIA V5 för CAD

     

    Vad som utförts:

    Marknadsundersökning har utförts mot konkurrenter och tidigare koncept framtagna av Volvo, sedan framtagning av olika koncept för vibrationsdämpare med justering i CATIA v5.

    De koncept som tagits fram jämförs sedan i en Pugh-matris, viktiga egenskaper som pris, tillverkningsbarhet, monteringsbarhet jämförs med den nuvarande dämparen.

     

    Resultat av Pugh-matrisen:

    Koncept 2 och 4 var bäst i denna analys, båda fick lika mycket poäng i sin jämförelse, dock utfördes analysen utan en kostnadsberäkning.

     

    Diskussion och Slutsats:

    Två av koncepten är bättre lämpade att fortsätta utveckla, koncept 2 och 4, detta av både kostnadsskäl samt att de kan ändras för att ge en tillräcklig justering.

    Koncept 1 kan användas ett kortare tag, då det löser vissa problem som de har haft vid montering.

    Slutsatsen är att det går att göra olika koncept med justering för vibrationsdämpare.

    Den svåra delen att lösa är hur man ska kunna justera dämparna med stängd frontlucka.

    Fulltekst (pdf)
    fulltext
  • 19.
    Kullgren, Anders
    et al.
    Department of Applied Mechanics, Folksam Research, Chalmers University of Technology, Sweden.
    Stigson, Helena
    Department of Clinical Neuroscience, Folksam Research, Karolinska Institutet, Sweden.
    Krafft, Maria
    Umeå universitet.
    Development of whiplash associated disorders for male and female car occupants in cars launched since the 80s in different impact directions2013Inngår i: 2013 IRCOBI Conference Proceedings, International Research Council on the Biomechanics of Injury , 2013, s. 51-62, artikkel-id IRC-13-14Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim was to investigate the development of Whiplash Associated Disorders (WAD) leading to long-term consequences for drivers separated for gender in cars introduced at different year intervals and in different impact directions. An additional aim was to analyze the influence of various whiplash preventive concepts on WAD in rear impacts. The developments were studied for cars grouped into 5-year intervals according to year of introduction separated for frontal, side and rear-end impacts and for gender. All drivers (24,452) reporting WAD during the years 1998-2012, and those reporting symptoms > 1 month as well as those with permanent impairment, were included. Whiplash preventive concepts were grouped according to car make and concept. A reduction in risk of long-term consequences after reporting initial symptoms of WAD were found in rearend and side impacts comparing cars introduced on the market 1980-84 and 2005-2009. No reduction was found in frontal impacts. This clearly shows that more focus on preventive interventions for frontal impacts is needed. Existing seat concepts aimed at lowering the risk of WAD were found to reduce the risk of long-term consequences after reporting initial symptoms of WAD. However, seats with energy absorption in the seat back, passive seats or reactive seats are more effective for females than seats with Reactive Head Restraints, which showed no major reduction of WAD with long-term consequences compared with standard seats.

  • 20.
    Leiviskä, Albin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Load generation on a CV90 track system using multibody dynamics2021Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 21.
    Lenkeit Gesser, Malin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Designhögskolan vid Umeå universitet.
    Carrie: Handla miljövänligare2019Independent thesis Basic level (degree of Bachelor of Fine Arts), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Ett av de mest hotande problemen idag är vad som händer med miljö. Ett stort problem är utsläpp. En stor bidragande faktor är den tanklösa användningen av fordon drivna av fossila bränslen. Ett sätt att kunna ta ett litet steg i rätt riktning, är att anpassa våran livstil och till exempel minska på användningen av bilen. Men även att allmänt göra mer medvetna val i vardagen.

    Målet med detta projektet är att göra just detta lite enklare. Att hjälpa dig transportera dina matvaror exempelvis från mataffären till hemmet.Processen för att komma fram till det som blev slutprodukten, började med intervjuer av användare. Därefter producerades skisser som visades för en testgrupp, för att samla feedback. Fysiska tester utfördes, innan det slutgiltiga konceptet nåtts: En vagn man kan använda på fyra sätt. Man kan skjuta den framför sig medan man går, eller dra den efter sig, man kan använda den som sparkcykel eller man kan koppla den till en cykel.

    Fulltekst (pdf)
    fulltext
  • 22.
    Lundberg, Petter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Investigation of the transient nature of rolling resistance on an operating Heavy Duty Vehicle2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    An operating vehicle requires energy to oppose the subjected driving resistances. This energy is supplied via the fuel combustion in the engine. Decreasing the opposing driving resistances for an operating vehicle increases its fuel efficiency: an effect which is highly valued in today’s industry, both from an environmental and economical point of view. Therefore a lot of progress has been made during recent years in the area of fuel efficient vehicles, even though some driving resistances still rises perplexity. These resistances are the air drag Fd generated by the viscous air opposing the vehicles propulsion and the rolling resistance Frr generated mainly by the hysteresis caused by the deformation cycle of the viscoelastic pneumatic tires.

    The energy losses associated with the air drag and rolling resistance account for the majority of the driving resistances facing an operating vehicle, and depends on numerous stochastic and ambient parameters, some of which are highly correlated both within and between the two resistances. To increase the understanding of the driving mechanics behind the energy losses associated with the complexity that is rolling resistance, a set of complete vehicle tests has been carried out. These tests were carried out on the test track Malmby Fairground, using a Scania CV AB developed R440 truck equipped with various sensors connected in one measurement system. Under certain conditions, these parameters can allow for an investigation of the rolling resistance, and a separation of the rolling resistance and air drag via explicit subtraction of the air drag from the measured traction force. This method is possible since the aerodynamic property AHDVCd(β) to some extent can be generated from wind tunnel tests and CFD simulations.

    Two measurement series that enable the above formulated method of separation were designed and carried out, using two separate measurement methods. One which enables the investigation of the transient nature of rolling resistance as it strives for stationarity, where the vehicle is operated under constant velocities i.e. no acceleration, and one using the well established method of coastdown, where no driving torque is applied.

    The drive cycles spanned a range of velocities, which allowed for dynamic and stationary analyses of both the tire temperature- and the velocity dependence of rolling resistance. When analysing the results of the transient analysis, a strong dependence upon tire temperature for given constant low velocity i.e. v ≤ 60 kmh−1 was clearly visible. The indicated dependency showed that the rolling resistance decreased as the tire temperature increased over time at a given velocity, and vice versa, towards a stationary temperature and thereby rolling resistance. The tire temperature evolution from one constant velocity to another, took place well within 50 min to a somewhat stationary value. However, even though the tire temperature had reached stationarity, rolling resistance did not; there seemed to be a delay between stationary tire temperature, and rolling resistance. The results did not indicate any clear trends for v ≥ 60 kmh−1, where the results at v = 80 kmh−1 were chaotic. This suggests that some additional forces were uncompensated for, or that the compensation for air drag was somehow wrongly treated at higher velocities.

    Several factors ruled out any attempts at proposing a new rolling resistance model. These included: the chaotic results for v = 80 kmh−1, the delayed rolling resistance response upon tire temperature stabilization, and the lack of literature support for the observed tendency. The results from the coastdown series on the other hand, showed good agreement with a dynamical model suggested in literature. The stationary temperature behaviour for the considered velocity range at assumed constant condition is also supported in literature.

    Finally, an investigation of the aerodynamic property AHDVCd inspired by ongoing work in ACEA (European Automobile Manufacturers’ Association), was carried out assuming both zero and non-zero air drag at low velocities. The results indicated surprisingly good agreement with wind tunnel measurements, especially when neglecting air drag at low velocities: as suggested by ACEA. 

    Fulltekst (pdf)
    M.Sc.Thesis
  • 23.
    Löfgren, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Accuracy of transient versus steady state forces on a rudder operating in a propeller slipstream2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In computational fluid dynamics (CFD), a transient simulation is in general more costly than computing the steady state of the system, if such a state exists. The velocity field produced by the propeller blades upstream of a rudder is transient in nature, and rudder design using CFD may therefore become very time-consuming. If a steady solution could accurately predict the performance of the rudder, such an approach would be favourable. The aim of the present study was to assess the possibility to accurately predict the performance of a rudder operating in a propeller slipstream using steady state simulations, e.g. an actuator disk model (ADM). For this reason, the performance of the two-dimensional NACA 0021 rudder section submitted to a sinusoidal transverse gust, representing a transient propeller slipstream, was simulated using ANSYS Fluent. The predicted force coefficients are presented for a number of gust amplitudes, mean angles of attack and reduced frequencies of the transverse gust. The simulations have shown that the modelling error introduced when predicting the performance in a steady state is highly dependent on all these parameters of the actual transient flow, and that the steady result may be a severe over- or under-prediction of the real performance of the rudder. Heavily loaded propellers are suspected to be less suitable for ADM modelling in rudder performance prediction. The predicted unsteady lift coefficient was compared to the linear theories of Horlock and Sears, and the agreement was fair at zero mean angle of attack but poor at a mean angle of attack of 10°. It was also found that the predicted performance of the rudder was significantly altered when the chord based Reynolds number was increased by a factor of 10, which has implications on the validity of model-scale simulations. The effect of including turbulent transition modelling for some of the simulations was also investigated, and the discrepancy in predicted performance was found to be considerable. Due to the formation of a laminar separation bubble the predicted trailing edge separation and viscous stress on the rudder were significantly decreased, leading to better overall performance.

    Fulltekst (pdf)
    fulltext
  • 24.
    Mikkelsen, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Development, Modelling and Control of a Multirotor Vehicle2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The interest of drones in all forms has exploded in the recent years. The development of multirotor vehicles such as quadcopters and octocopters, has reached a point where they are cheap and versatile enough to start becoming a part of everyday life. It is clear to say that the future applications seem limitless. This thesis goes through the steps of development, modelling and control design of an octocopter system. The developed octocopter builds on a concept of using the mini computer Raspberry Pi together with the code generation functionality of Matlab/Simulink. The mathematical modelling of the octocopter includes the thrust and torques generated by the propellers, added with gyroscopic torque. These are combined with the aerodynamic effects caused by incoming air. The importance of modelling the later mentioned effects has increased with the demand of precise controlled extreme manoeuvres. A full state feedback based hybrid controller scheme is designed against a linearized model, which makes use of the motor dynamics. The controllers show good performance in simulations and are approved for flight tests, which are conducted on two separate occasions. The octocopter makes two successful flights, proving that the concept can be applied on multirotor vehicles. However, there is a miss-match between the mathematical model and the physical octocopter, leaving questions for future work.

    Fulltekst (pdf)
    DevelopmentModellingAndControlOfAMultirotorVehicle
  • 25.
    Nordström, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Advanced Modelling and Energy Efficiency Prediction for Road Vehicles2020Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis presents a first real world case-study of road transport operations that use the COVER format, in which the driver and the vehicle are regarded as separate entities. This format enables a complex representation of the transport operation that potentially better describe reality compared to the conventional representation used in today’s certification tools. The representation of operations treated in this thesis is called Operating Cycles and has been used to fully describe three representative transport missions from a case-study truck. Stochastically generated operating cycles have been used to create a large data set and thus prevent overfitting of specific cycles. The Operating Cycle-representation allowed for fair comparison between vehicle designs and ultimately manifested a vehicle composition that reduced the fuel consumption by nearly 10% for the same kind of transport operations.

    Fulltekst (pdf)
    Advanced Modelling and Energy Efficiency Prediction for Road Vehicles
  • 26. Otxoterena, Paul
    et al.
    Björnstig, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Lindquist, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Post-collision fires in road vehicles between 2002 and 20152020Inngår i: Fire and Materials, ISSN 0308-0501, E-ISSN 1099-1018, Vol. 44, nr 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The loss of human lives and body injuries due to post-crash fires, either by smoke inhalation or due to burn injuries, are unfortunately not uncommon. The literature indicates that fire events related to crashes are still a significant problem. The increased combustible load in newer vehicles is an important factor to be taken into account for the fire safety, as well as their potential to release toxic fumes while burning. Trends indicate that the survivable collision energy will continue to increase, and, at the same time, the probability of post-crash fires rises with the collision energy. This means that the occupants of a vehicle may probably survive a high-energy collision but might sustain severe injuries or death due to a post-collision fire. This work reports a literature and interview study about post-crash fires including statistics on the causes and dynamics of post-crash fires in road vehicles based on the literature, crash and incident reports, as well as on interviews with medicine specialists. Results from this study indicate that fires in vehicles which originated by a collision event are a problem that remains to be solved.

  • 27. Pipkorn, Bengt
    et al.
    Iraeus, Johan
    Lindquist, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Puthan, Pradeep
    Bunketorp, Olle
    Occupant injuries in light passenger vehicles: A NASS study to enable priorities for development of injury prediction capabilities of human body models2020Inngår i: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 138, artikkel-id 105443Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To prioritize how the development of mathematical human body models for injury prediction in crash safety analysis should be made, the most frequent injuries in the NASS CDS data from 2000 to 2015 were analyzed. The crashes were divided into seven types, from front to side. Non-minor injuries (AIS2+) were analyzed in two steps. In the first step, a grouping was made according to the AIS definition of body regions: head, face, neck, thorax, abdomen and pelvic contents, spine, upper extremities (including shoulder girdle) and lower extremities (including pelvis). In a second step, the body regions were divided in organs, parts of the spine, and parts of the extremities. The three most often injured anatomical structures of each body region were estimated for drivers and front seat passengers in each type of crash. For drivers, an injury risk greater than 2.4 % was found for the lower extremities (pelvis) and the head (concussion) in side oblique near side impacts, for the head in frontal oblique near side impacts (concussion) and for the lower extremities (ankle joint) in frontal impacts. For passengers, an injury risk greater than 2.4 % was found for the thorax (lungs) in side near side impacts, for the head (concussion) in front oblique near side impacts, and for the thorax (sternum) and the upper extremities (wrist, hand) in frontal impacts. Future development of human body models should focus on injuries to the head, thorax and the lower extremities. More specifically, it should focus on concussion in all impact directions and on rib and pelvic fractures in side near side impacts and in side oblique near side impacts.

  • 28.
    Pipkorn, Bengt
    et al.
    Autoliv Research, Vårgårda, Sweden.
    Lopez-Valdes, Francisco J.
    Impact Laboratory (I3A), University of Zaragoza, Spain.
    Juste-Lorente, Oscar
    Impact Laboratory (I3A), University of Zaragoza, Spain.
    Maza, Mario
    Impact Laboratory (I3A), University of Zaragoza, Spain.
    Sunnevång, Cecilia
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Study of the kinematics of the THOR dummy in nearside oblique impacts2016Inngår i: 2016 IRCOBI Conference Proceedings, International Research Council on the Biomechanics of Injury , 2016, s. 637-648Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Oblique and small-overlap crashes are the second most common frontal crash type leading to fatal outcome. This study discusses a simplified test rig suitable to analyse the performance of the THOR dummy in oblique impacts. Secondly, this paper compares the kinematics and dynamics of the THOR dummy under the loading of two types of seat belts. Last, the study compares the response of the THOR finite element (FE) model to the one of the physical dummy. By means of mathematical simulations with the THOR FE model different seat designs were evaluated so that the dummy kinematics could approximate those observed in real vehicles. Thereafter two different three-point seat belt systems were evaluated via physical and computer-modelled sled tests: a pretensioned (shoulder retractor and lap) force-limiting seat belt (reference seat belt) and an innovative belt in which the shoulder and the lap bands were split (split buckle). The study shows that THOR pelvic displacement was significantly reduced in a realistic manner by using a modified angled seat in comparison to the originally flat seat of the test fixture. The THOR dummy was able to discriminate between the two seat belt systems and the results suggest that the split buckle restraint has the potential to achieve significant injury reducing benefits in the oblique loading condition. In the comparison of the THOR mathematical and mechanical models, a total CORA score of 0.62 was obtained for the reference seat belt comparison and a score of 0.60 was obtained for the split buckle comparison.

  • 29.
    Romano, Luigi
    et al.
    Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Hörsalsvägen 7A, Gothenburg, Sweden.
    Johannesson, Par
    RISE Research Institutes of Sweden, Gibraltargatan 35, Gothenburg, Sweden.
    Nordström, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Bruzelius, Fredrik
    Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Hörsalsvägen 7A, Gothenburg, Sweden.
    Andersson, Rickard
    Volvo AB, Sweden.
    Jacobson, Bengt
    Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Hörsalsvägen 7A, Gothenburg, Sweden.
    A classification method of road transport missions and applications using the operating cycle format2022Inngår i: IEEE Access, E-ISSN 2169-3536, Vol. 10, s. 73087-73121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When dealing with customers, original equipment manufacturers (OEMs) classify vehicular usage by resorting to simplified, often colloquial, descriptions that allow for a rough understanding of the operating conditions and the user’s needs. In this way, the information retrieved from the customers is exploited to guide their choices in terms of vehicle design and configuration, based on the characteristics of the transport application, labeled using intuitive metrics. However, a common problem in this context is the absence of any formal connection to lower levels of representation that might effectively be used to assess vehicular energy performance in simulation, or for design optimization using mathematical algorithms. Indeed, both processes require more accurate modeling of the surroundings, including exhaustive information about the local road, weather, and traffic conditions. Therefore, starting with a detailed statistical description of the environment, this paper proposes a method for mathematical classification of transport missions and applications within the theoretical framework of the operating cycle (OC). The approach discussed in the paper combines a collection of statistical models structured hierarchically, called a stochastic operating cycle (sOC), with a bird’s-eye view description of the operating environment. The latter postulates the existence of different classes, which are representative of the usage and whose definition is based on simple metrics and thresholds expressed mathematically in terms of statistical measures. Algebraic expressions, called operating classes in the paper, are derived analytically for all the stochastic models presented. This establishes a connection between the two levels of representation, enabling to simulate longitudinal vehicle dynamics in virtual environments generated based on the characteristics of the intended application, using log data collected from vehicles and/or information provided by customers. Additionally, the relationships between the two descriptions are formalized using elementary probability operators, allowing for an intuitive characterization of a transport operation. An example is adduced to illustrate a possible application of the proposed method, using six sOCs parametrized from log data collected during real-world missions. The proposed approach may facilitate the interaction between OEMs, customers, and road operators, allowing for planning of maintenance, and optimization of transport missions, components, and configurations using standard procedures and routines.

    Fulltekst (pdf)
    fulltext
  • 30.
    Sadeghi, Babak
    et al.
    Luleå University of Technology, Sweden.
    Westerlund, Per
    Luleå University of Technology, Sweden.
    Salles, Rafael S.
    Luleå University of Technology, Sweden.
    Wilén, Jonna
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Radiated emissions from an electric railway: review of methods and measurements mainly from 9 khz to 150 khz2023Inngår i: CIRED 2023 proceedings, Rome: CIRED - congrès international des réseaux electriques de distribution, 2023, Rom: CIRED - Congrès International des Réseaux Electriques de Distribution, 2023 , 2023, Vol. 2023, nr 6, s. 3694-3698Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, a review has been done based on the study of articles and documents related to radiated electromagnetic emissions of the railway system, an example of measurements is presented, and the requirement of a unique procedure is discussed to obtain repeatable and reproducible electromagnetic compatibility (EMC) measurements. Regarding the measurement results, it could be noted that in the 9 kHz to 150 kHz range, some frequencies are dominant which might be generated from pantograph arcing and onboard power electronic devices.

  • 31.
    Samuelsson, Ted
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Load Unit Geometry Optimization for Heavy Duty Machinery2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The construction equipment industry is developing at a fast pace, increasing the expectation on the next-generation machines. Wheel loaders and backhoe loaders are part of this evolution and all subsystems in those machines need to be developed to meet the high demands in energy eciency and productivity. One of the most important parts of the wheel loader is the loading unit. This is traditionally designed using highly experienced engineers and CAD software. To simplify the early stages of this process was an optimization tool developed to generate a design outlay. The optimization will minimize the mass of the linkage since unnecessary weight will lower the eciency. The minimum can be found by moving the joints and adjusting the shape of the device. The optimization will also include constraints to assure the correct performance of the linkage. Since there are a high number of design variables, a gradient-based optimization method was used. A finite element solver was also implemented to calculate the forces and stresses in the linkage. The linkages studied in this report are one from a typical wheel loader and one from a backhoe loader. Since these machines are extremely versatile, and used formany diferent tasks, two sets of constraints are compiled. One of the constraint sets yields a linkage suitable for machines only equipped with bucket, while the other results in an all-round linkage suitable for most tools and applications. The optimized linkages are compared to existing devices. The results show that there are some improvements possible and that the software could be used to help designers. However, the optimization problem is hard to solve due to non-smooth constraints functions and numerical instabilities. This issue could be overcome by diferent means, like using automatic diferentiation, a non-gradient based optimization method, decreasing the number of constraints or decreasing the number of design variables.

    Fulltekst (pdf)
    fulltext
  • 32.
    Schoultz, Joakim
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Wikberg, Tobias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Konstruktion och vidareutveckling av SIRIUS skidbalk2021Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna kandidatrapport behandlar ett arbete resulterande i en ökning av hållfastheten hos en skidbalk ingående i bandvagnen BvS10. Projektet har utförts på uppdrag av BAE Systems Hägglunds under deras SIRIUS-samarbete med Luleå tekniska universitet. Inom SIRIUS har många utvecklingsprojekt startats, varav ett är E-TED dit det här arbetet hör. Balken har tappat avsevärd hållfasthet då hål utformats i dess yttre sida för att rymma komponenter. Detta har gjorts av anledningar utvecklade inom E-TED. Syftet var därför att utveckla en konceptuell och användbarskidbalk för bandvagnen med målsättningen att erhålla en lika bra eller bättre hållfasthet relativt ursprungsbalken.

    För att nå målet itererades arbetet mellan finita elementmetoden (FEM) och computer-aided design (CAD) i programmen CATIA V5, ANSA, ABAQUS och META för utveckling av koncept. Itereringen resulterade i två konceptbalkar, varav den sista var fördelaktigast. CATIA brukades för CAD och de resterande programmen brukades respektive som förbehandlare, problemlösare och efterbehandlare för FEM. Av dessa tre utfördes de två första med hjälp av beräkningsavdelningen på BAE Systems Hägglunds och det sista utfördes av författarna. Ursprungs- och konceptbalkarna testades med fem lastfall motsvarande de extremaste förhållanden som uppmätts vid körning av bandvagnen. Förstärkningarna implementerades därefter baserad på teori gällande böj- och vridmotstånd för homogena balkars kvadratiska- och rektangulära tvärsnitt.

    Spänningsanalys av den slutgiltiga konceptbalken uppvisade effektivspänningar överskridande materialets sträckgräns för tre av lastfallen. För de två mest problematiska av dessa tre fall utformades en analys av kvarvarande plastisk töjning respektive deformation. Detta påvisade att kvarvarande plastisk töjning respektive deformation var i samma storleksordning som vid tidigare undersökningar av idag driftsatta skidbalkar. Alltså drogs slutsatsen att det är möjligt att skapa en SIRIUS-skidbalk med minst lika bra hållfasthet som ursprungsbalken samt att slutgiltiga konceptbalken, ur ett hållfasthetsperspektiv, är redo för användning.

    Fulltekst (pdf)
    fulltext
  • 33.
    Strandroth, J.
    et al.
    Chalmers University of Technology, Sweden.
    Nilsson, P.
    Chalmers University of Technology, Sweden.
    Sternlund, S.
    Chalmers University of Technology, Sweden.
    Rizzi, M.
    Chalmers University of Technology, Sweden.
    Krafft, M.
    Umeå universitet.
    Characteristics of future crashes in Sweden: Identifying road safety challenges in 2020 and 20302016Inngår i: 2016 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, International Research Council on the Biomechanics of Injury , 2016, s. 47-60, artikkel-id IRC-16-15Konferansepaper (Fagfellevurdert)
    Abstract [en]

    It has been proposed by the European Commission that the number of road fatalities within the European Union should move close to zero by 2050. In response to that, Sweden has set out to revise the national road safety targets of 2020 and 2030. In order to address future safety challenges, there is a need to consider the characteristics of future crashes. The objective of this study was therefore to quantify and investigate the characteristics of severe crashes in 2020 and 2030. Injury crashes were reduced from a baseline in 2014 to a given time in the future based on the implementation of safety interventions. The material consisted of hospital admission data with AIS diagnoses. Results show that the actions planned to be taken in Sweden between now and 2020 and 2030 will continue to increase the safety level for car occupants, but are estimated to be insufficient for vulnerable road users. It was concluded that there is a need to define a safety system for vulnerable road users that takes a holistic approach to sustainability by including both injury prevention measures and measures to encourage more health-promoting and fossil-free modes of transport.

  • 34.
    Thermaenius, Filip
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Björnstig, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi.
    Svensson, Johan
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Westman, Anton
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Kirurgi. Department of Anaesthesia and Intensive Care Medicine, Karolinska University Hospital, Huddinge, Sweden.
    Fatalities in Swedish fire-related car crashes from a toxicologic perspective2023Inngår i: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 24, nr 1, s. 21-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: Vehicle materials developments raise concerns about new patterns of vehicle fire toxic gas emissions. This study aimed to describe toxicologic components in a recent material of fatal car crashes on Swedish roads in which the vehicle caught fire and compare the results to a previous material.

    Methods: Retrospective registry study. All fatal car crashes with fire in Sweden 2009–2018 were extracted from the Swedish Transport Administration’s In-Depth Studies Database and compared with an earlier study of the time period 1998–2008.

    Results: A total of 79 crashes and 94 fatalities were included. Carbon monoxide (COHb) blood levels >10% were found in 13 cases. Hydrogen cyanide (HCN) blood levels 0.1–1.7 µg/g were found in 10 cases. In 31 of the cases the person had a blood alcohol level (BAC) >0.2‰, which is the legal driving limit in Sweden. A total of 15 people died due to burn injuries and 2 individuals died due to toxic gas emissions without any other fatal traumatic injury. Total number of deaths in fire-related crashes halved from 181 (1998–2008) to 94 (2009–2018) but the percentage of fatalities in burning vehicles was unaltered (5% vs. 6%). The proportion of fatalities with HCN in the blood increased from 2% between 1998–2008 to 10% during 2009–2018 (p = 0.006). The age of the car involved in a crash increased by 0.26 years per calendar year (p = 0.001).

    Conclusions: The proportion of fatalities with measured levels of HCN in the blood has increased. Eleven of the 15 burn injury fatalities had high levels of alcohol, HCN, or COHb, possibly contributing to an inability to leave a burning vehicle. Faster rescue brought by improved specific education and training of ambulance and rescue services personnel may be of future importance, as may on-scene antidote administration and revised regulations of vehicle flammability.

    Fulltekst (pdf)
    fulltext
  • 35.
    Tingvall, Claes
    et al.
    Traffic Safety, Swedish Transport Administration, Chalmers University of Technology, Sweden.
    Ifver, Jan
    Swedish Transport Agency, Sweden.
    Krafft, Maria
    Umeå universitet.
    Kullgren, Anders
    Traffic Safety Research, Folksam, Chalmers University of Technology, Sweden.
    Lie, Anders
    Swedish Transport Administration, Chalmers University of Technology, Sweden.
    Rizzi, Matteo
    Folksam, Chalmers University of Technology, Sweden.
    Sternlund, Simon
    Swedish Transport Administration, Chalmers University of Technology, Sweden.
    Stigson, Helena
    Folksam, Karolinska Institute, Sweden.
    Strandroth, Johan
    Swedish Transport Administration, Chalmers University of Technology, Sweden.
    The consequences of adopting a MAIS 3 injury target for road safety in the EU: A comparison with targets based on fatalities and long-term consequences2013Inngår i: 2013 IRCOBI Conference Proceedings, International Research Council on the Biomechanics of Injury , 2013, s. 1-11Konferansepaper (Fagfellevurdert)
    Abstract [en]

    It has been proposed in the European Union (EU) to adopt a Maximum Abbreviated Injury Scale (MAIS) of 3 or greater as the basis for a road safety target. To have a common definition of serious injury across the EU is in itself very positive. In this study, fatalities, MAIS 3+, MAIS 2+ and injuries leading to permanent medical impairment (PMI) were used to identify problem scenarios. A national data set of injuries reported to Swedish hospitals from 2007 to 2012 (STRADA) was used. Police-reported injuries were also taken into account. The results showed that, depending on the data source and injury rating method, problem scenarios differed substantially. While fatalities were dominated by vehicle occupants in high-speed environments, vulnerable road users in urban areas were in greater focus as a result of lowered thresholds for injury or impairment levels. Bicyclists in particular have many injuries at less severe, yet significant, levels. There is a particular need to consider certain diagnoses which lead, relatively often, to long-term consequences at the AIS 1 level. To achieve a better injury and consequence scenario, data from the medical system are an essential prerequisite.

  • 36.
    Wahlström, Dennis
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Probabilistic Multidisciplinary Design Optimization on a high-pressure sandwich wall in a rocket engine application2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A need to find better achievement has always been required in the space industrythrough time. Advanced technologies are provided to accomplish goals for humanityfor space explorer and space missions, to apprehend answers and widen knowledges. These are the goals of improvement, and in this thesis, is to strive and demandto understand and improve the mass of a space nozzle, utilized in an upperstage of space mission, with an expander cycle engine. The study is carried out by creating design of experiment using Latin HypercubeSampling (LHS) with a consideration to number of design and simulation expense.A surrogate model based optimization with Multidisciplinary Design Optimization(MDO) method for two different approaches, Analytical Target Cascading (ATC) and Multidisciplinary Feasible (MDF) are used for comparison and emend the conclusion.

    In the optimization, three different limitations are being investigated, designspace limit, industrial limit and industrial limit with tolerance. Optimized results have shown an incompatibility between two optimization approaches, ATC and MDF which are expected to be similar, but for the two limitations, design space limit and industrial limit appear to be less agreeable. The ATC formalist in this case dictates by the main objective, where the children/subproblems only focus to find a solution that satisfies the main objective and its constraint. For the MDF, the main objective function is described as a single function and solved subject to all the constraints. Furthermore, the problem is not divided into subproblems as in the ATC.

    Surrogate model based optimization, its solution influences by the accuracy ofthe model, and this is being investigated with another DoE. A DoE of the full factorial analysis is created and selected to study in a region near the optimal solution.In such region, the result has evidently shown to be quite accurate for almost allthe surrogate models, except for max temperature, damage and strain at the hottestregion, with the largest common impact on inner wall thickness of the space nozzle. Results of the new structure of the space nozzle have shown an improvement of mass by ≈ 50%, ≈ 15% and ≈ -4%, for the three different limitations, design spacelimit, industrial limit and industrial limit with tolerance, relative to a reference value,and ≈ 10%, ≈ 35% and ≈ 25% cheaper to manufacture accordingly to the defined producibility model.

    Fulltekst (pdf)
    fulltext
  • 37.
    Öhrman, Jakob
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Evaluation of a CFD method for estimating aerodynamic loads on external stores on JAS 39 Gripen2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Loads determination for external stores on fighter aircraft is an important task for manufacturers in ensuring the safe operation of their aircraft. Due to the large number of possible store combinations, wind tunnel tests – the primary approach to obtaining loads data – cannot be performed for all configurations. Instead, supplementary techniques to estimating loads are necessary. One approach is to use information from another store and adapt it, using so-called scaling methods, to the non-tested store.

    In this thesis, a scaling method combining the results of computational fluid dynamics (CFD) simulations, for both a non-tested and a reference store, with existing wind tunnel data for the reference store, is thoroughly examined for a number of different stores, angles of attack, sideslip angles and Mach numbers. The performance of the proposed scaling method is assessed in relation to currently used scaling methods, using non-parametric and multivariate statistics.

    The results show no definitive improvement in performance for the proposed scaling method over the current methods. Although the proposed method is slightly more conservative, considerable variability in the estimates and an increased time consumption for scaling leads the author to advise against using the proposed method for scaling aerodynamic loads on external stores.

    Fulltekst (pdf)
    ohrman_2011_evaluation-of-a-cfd-method
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