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  • 151. Jansson, Agneta
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Mechanical properties of starch - a biodegradable polymer2002Conference paper (Refereed)
  • 152.
    Jernberg, Hannes
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Utökade tillämpningsmöjligheter för turbinlösning i våtpartiet hos tissuemaskiner: Konceptförslag som möjliggör tillämpning av turbinlösning för maskiner vars banbredd är bredare än 2,9 meter2014Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    AbstractThis thesis is the final part of the Innovation and Design Engineering Programme (180 ECTS credits)at the Faculty of Health, Nature and Engineering Science at Karlstad University. The extent of thisthesis is 22.5 ECTS credits and has been performed independently by Hannes Jernberg during thespring of 2013. Metso Paper Karlstad AB is the task maker of this project, and Arvid Johansson is thecompany Representative. Metso Paper Karlstad AB is one of the world leading developer andmanufacturer of tissue paper machines.In the current situation, the company has developed and patented a power management systembased on a Cross Flow Turbine. The current construction is limited to a paper width of 2.9 meters.The company wants to take advantage of all the opportunities provided by the patents, to develop aturbine solution paper machine with a paper width that is wider than 5.5 meters, and give the abilityto manufacture paper for lower energy consumption which is an important part of the production asit is very energy intensive.Problems arise with the increasing length of the turbine, ultimately resulting in that the deflectionbecomes too big and that the momentums, due to the increased torque the turbine blades breaks.By applying the design process, this work has resulted in a number of potential solutions to theproblem. Sketches, LEGO and engineering methodologies have contributed to the good result.The recommended solution generated by this project is to place two regular sized turbines by 2.9meters. The first turbine is placed in its optimal position at the Driver side of the turbine, themomentum provided by the water is leaded by a shaft towards the engine side of the machine. Thesecond turbine is placed directly under the first shaft. This allows the second turbine take care of therest of the water and energy.

  • 153. Jernkvist, L O
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Determination of cylindrical elastic orthotropy in wood by use of digital speckle photography2000Conference paper (Refereed)
  • 154. Jernkvist, L O
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Experimental determination of stiffness variation across growth rings in Picea Abies2001In: Holzforschung 55 2001 pp 309-317Article in journal (Refereed)
  • 155.
    Johansson, Daniel
    et al.
    MSE Weibull AB.
    De Vin, Leo
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Omnidirectional Robotic Telepresence through Augmented Virtuality for Increased Situation Awareness in Hazardous Environments2009In: Systems, Man and Cybernetics: Conference Proceedings, IEEE , 2009, p. 6-11Conference paper (Refereed)
    Abstract [en]

    This paper proposes a novel low-cost robotic telepresence approach to situation awareness, initially aimed for hazardous environments. The robot supports omnidirectional movement, wide field of vision, haptic feedback and binaural sound. It is controlled through an augmented virtuality environment with an intuitive position displacement scheme that supports physical mobility. The operator thereby can conduct work away from danger whilst retaining situation awareness of the real environment.

  • 156.
    Johansson, Daniel
    et al.
    MSE Weibull AB.
    De Vin, Leo
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Towards Convergence in a Virtual Environment: Omnidirectional Movement, Physical Feedback, Social Interaction and Vision2012In: Mechatronic Systems, ISSN 1986-5147, Vol. 2, no 1, p. 11-22Article in journal (Refereed)
    Abstract [en]

    Movement, physical feedback, social interaction and vision are important factors for humans inthe real world, and therefore also in a virtual world whose aim is to mimic the real world. The effect of avirtual environment application could increase through the use of a human-computer interface that canmatch natural human capability in such areas, and several novel components are presented herein. Here,movement and feedback is gained through an omnidirectional walking surface that enables untetheredmovement throughout a virtual world without imposing physical restrictions. Although several differentapproaches exist to the mechanical problem of two-dimensional translation, an alternative top-downapproach can reduce complexity to one-dimensional space. Furthermore, interchange of subtle bodylanguage can be vital and achieved with a system that supports high fidelity in virtual texturerepresentation of users, which can be more powerful in some cases than virtual geometry. Also, a newapproach is taken to the design of a head mounted display with minimal weight through optics in the formof soft contact lenses, mounted directly on the eyes.

  • 157.
    Johansson, Emil
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bomfjädring till hjulgrävmaskin:  2012Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The task was to design a damping system to Volvo´s wheeled excavator EW160C with assignments from Swecon. The type of solution that would be relevant turned out to be a kind of accumulator system. By connecting an accumulator to the piston side of the cylinder, the accumulator operates as a shock absorber as the oil-flow from the cylinder of the crane, which moves up and down on uneven surfaces, flows into the accumulator and gets suppressed by means of a diaphragm or a piston in the accumulator that is pressurized by a gas. The oil flow attenuates when the gas is compressed.

    At the beginning of the thesis work, a project plan was made with a time schedule and a risk analysis. Then the research began for different types of aftermarket kits and companies that are working with this type of solutions. A meeting was arranged with Anders Tågmark who´s working for Hydac, a company that is selling hydraulic components. After the meeting we decided to cooperate. A decision was made that I should bring Anders concepts of the solution and Anders should give me examples of components that were needed. The research work also contained a study visit at Swecon in Eskilstuna, where the people that made the request about this work in the beginning was interviewed. At this meeting they made a priority list of what they thought was most important to have in mind in the concept development. The result of the research was that the solution should be simple and as cheap as possible, so it wouldn´t compete with a solution that Volvo might develop in the future. The goal in this project was therefor to make an aftermarket kit. Some of the requirements was that the damping system was allowed to cost between 15-25 000 Swedish crowns for the customers to buy, and that the system should be easy and quick to mount on the machine.

     

    The main questions of the concept development, was which type of accumulator that should be used and where to place the system. One of the concepts was to place it on the boom-cylinders, and the other concept was to place it on the tilt-cylinder. It turned out that both concepts met the cost requirements from Swecon in terms of components. However, costs will be added for the completion of the solution for manufacturing, mounting, purchasing and spare parts support.

    The result was to use a piston-accumulator and place it on the tilt-cylinder, because the concept for the tilt-cylinder was simpler and less expensive

  • 158.
    Johansson, Gustaf
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Chassiintegrerade lastceller: Installation i fjädersäte på Scania tandemboggibakaxlar2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis presented in this report has been made on behalf of Scania and their basic frame design department with the subject to solve an implementation of a weight sensing system in the chassis. The system is supposed to be implemented in the seat springs, and the reason for this is that all the force will have to go through the weight sensing transducers. With all the force going through the transducers the weight sensing system will not be sensitive for the differences in tolerances from manufacturing. The transducers could be pre-calibrated to avoid a calibration of the whole vehicle after it’s completed from the manufacturing line.

    Weight sensing systems is today a reality in trucks with air springs. Complete systems is also sold in the big aftermarket for trucks. None of Scanias competitors have a solution for this as of today.

    The thesis was from start limited to only process the BT-301S bogie. A system will likely be easy to adapt to the other bogies with small modifications.

    Through the thesis possible problems are illuminated to understand the function and make a properly working weight sensing system. In the present bogie system the main problem for a proper function is the frictional forces that appears in the surface between the spring and the spring seat. 

    In the report a proposition with a rubber part between the spring and the spring seat is introduced, with the idea to get around the known problems with the frictional forces. The rubber itself does produce a reaction force when deformed, but the forces could through simulation be known, and hence compensated for. A rubber part under the spring would result in a contact surface much higher than today. A new spring, or a new version of the spring, will be needed for this solution to work.

    For the work to come, Scania need to decide what precision the weight sensing system need. But smaller decisions like the size and stiffness for the rubber part will also be needed. This thesis has only dealt with the bogie, but in a close future, the front axles need to be done. Much can likely be carried over from this thesis for that.

    A weight sensing might be possible to implement, but with what precision at uneven ground? Most likely will the variation in load on the transducers be too much. An approximation for the precision with a total span of 7% is realistic.

  • 159.
    Johansson, Hans
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Strip steel shapers as a result of non uniform plastic distributions. Part 12002Report (Other academic)
  • 160.
    Johansson, Hans
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Strip steel shapes as a result of non uniform plastic strain distributions. Part 22002Report (Other academic)
  • 161.
    Johansson, Hans
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Tillstånd i bandstål av betydelse för bandets form2002Report (Other academic)
  • 162. Johansson, K
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Single fibre fragmentation, SFF, as evaluation of fibre strength in brown stock washing and oxygen delignification2000Conference paper (Refereed)
  • 163. Johansson, K
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Germgård, Ulf
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Single fibre fragmentation, SFF, as evaluation of fibre strength in brown stock washing and oxygen delignification2001In: Appita Journal, Vol. vol 54 no 3Article in journal (Refereed)
  • 164.
    Jonsson, Jonathan
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Different coatings effect on tool-life when milling hardened tool steels2015Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Abstract

    This thesis work is about finding out which coating should be used for which hardened tool steel and this was done by testing different coated cutting tools in different kinds of tool steels. The thesis work is performed at Uddeholms AB together with Uddeholms AB in the department of R&D at machinability cooperating with eifeler-Vacotec GmbH. The thesis work is going on from the end of January to the start of June and is a part of the education as mechanical engineer at Karlstad University and includes a total of 22,5 hp. The objective after finished thesis work is to be able to leave a recommendation to Uddeholms AB which coating is most suitable for each tool steel. To be able to leave that recommendation cutting tests are performed in four different hardened steel grades from Uddeholms AB combined with seven different coatings from eifeler-Vacotec GmbH. Steel grades tested are NIMAX®, DIEVAR®, VANADIS® 10 and ORVAR® SUPREME and coatings tested are CROSAL®, EXXTRAL® and SISTRAL® in different compounds. ORVAR® SUPREME gave such a long cutting tool-life that it was left for further investigation due to time limits that the thesis work had. In the other three tool steels it was possible to get a recommendation out of the four coatings tested in each tool steel. The coating that is recommended for each tool steel is only based on the cutting tool lasting the longest in each tool steel. That is not how a recommendation usually is formed, however for this thesis work there is no time for checking all the aspects that is vital for a proper recommendation. In order to get a proper recommendation, further more aspects that are checked are for example:

    • Different cutting parameters (cutting speed, feed, etc.)
    • Different geometries on the cutting tool
    • Smoothness of the cutting tool and the coating

    In table 1 there is a compilation of which coating that was recommended for which tool steel.

    Table 1. This is a compilation of which coating that was recommended for which tool steel.

    NIMAX®               CROSAL® V1

    DIEVAR®             SISTRAL® Ultrafine

    VANADIS® 10    SISTRAL® S

  • 165.
    Karlsson, Anna
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Drömmen om den röda stugan: Huruvida varumärket Falu Rödfärg kan utvidgas till en ny produktkategori2012Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    "The dream of the Swedish red cottage" is a final thesis for the Innovation and Design Engineering program at Karlstad University. Anna Karlsson and Sebastian Karlsson have executed the project during spring term of 2011. The thesis includes 22,5 ECTS credits.

     

    Johan Molin, at Falu Rödfärg, has been the assigner for this project, as well as the project supervisor. Lennarth Wihk, industrial designer and lecturer at Karlstad University has been the academic supervisor for this project. Fredrik Thuvander, lecturer and professor has been the examiner.

     

    Falu Rödfärg is an outdoor paint for untreated and rough timber. The production and manufacturing of Falu Rödfärg have occurred since 1764, in the area around Falu copper mine. The color fabrication is a simple process and contains among other things boiling water, wheat flour and the characteristic red pigment. The pigment comes from the mineralization of the Falu copper mine, where red mull is created from ore with low copper content that has decomposed for a long time. The mine has been closed since 1992, after more than a thousand years of mining.

     

    The brand Falu Rödfärg is registered and legally protected and guarantees that the product is genuine Falu Rödfärg. Until 2006, there were a number of licensed manufacturers of Falu Rödfärg, who made and sold the color under their own names. The only requirement was that the brand had to be on the jar. As a first step in protecting and enhancing the brand, Falu Rödfärg made the decision that the color was only to be sold in one type of design, and the number of licensees was cut down. The reaction to this action was that several copies emerged on the market and Falu Rödfärg lost some of its ground. In 2008, Falu Rödfärg took over total responsibility of manufacturing and sales.

     

    The purpose of this project is to provide a basis and suggestions for products in a new product category to which Falu Rödfärg can extend their brand. The goal is to identify a proposal for an appropriate product category to which the brand can be extended, and produce recommendations for products which fit to the new category.

     

    The product category is subsequently proposed to the category “Outdoor environment / Garden” and the prototypes developed during the project are based on an extensive market research with respect to the category. Both needs and desires of the consumers, as well as the products that are available in today’s market have been identified.

     

    Through concept generation, concept evaluation and processing the project team thereby developed three prototypes that fit to the new product category, and can form the basis for Falu Rödfärg’s brand extension.

     

    Products designed for and developed to the garden market may be an appropriate product category to which Falu Rödfärg can extend their brand. An additional consumer research is needed to locate the inherent associations of the brand, and an evaluation of the adequacy considering the product category from a consumer point of view, from which the company’s continued brand management can proceed.

  • 166.
    Karlsson, Patrik
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    The early stage of galling2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In sheet metal forming (SMF) of materials such as stainless steels there is a major problem with transfer and accumulation of sheet material to the metal forming tool surface. The problem is known as galling; a kind of severe adhesive wear, which results in severe scratching of produced parts. In this thesis, galling observed in contacts between tool steels and stainless steel sheets under lubricated sliding conditions was studied, focusing on the early stage of galling. It was found that changes in friction cannot be used as galling indicator in the early stage of galling because transfer and accumulation of sheet material happens even though friction is low and stable. The progression of galling is influenced by tool steel damage occurring around the tool steel hard phases caused by sheet material flow, which results in formation of wear-induced galling initiation sites. A correlation between the critical contact pressure to galling and sheet material proof stress was found. Galling happened at lower pressures for sheet material with lower proof stress possibly due to easier sheet material flow, resulting in quicker tool damage. Material transfer and tool steel damage were delayed for tool steels comprising homogenously distributed, small and high hard phases. Additionally, the galling resistance was higher for tool steels with higher hardness due to decreased tool steel damage. In a comparison between observations of the worn tool surfaces after wear tests and calculations in FEM it was found that material transfer did not take place at regions with highest contact pressures but at regions with highest plastic strains. The results obtained in this thesis indicate that tool steel damage and sheet material flow occurring in the contact during sliding are important factors influencing galling.

  • 167.
    Karlsson, Patrik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Eriksson, Jenny
    Dalarna University.
    Gåård, Anders
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Olsson, Mikael
    Dalarna University.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Galling resistance evaluation of tool steels by two different laboratory test methods for sheet metal forming2012In: Lubrication Science, ISSN 0954-0075, E-ISSN 1557-6833, Vol. 24, no 6, p. 263-272Article in journal (Refereed)
    Abstract [en]

    Adhesive accumulation of work material on the tool surface is today a major problem in many sheet metal-forming applications. Different laboratory test methods are used to investigate galling with respect to different tool materials, lubricants and process conditions. In the present study, the galling resistance of a modern nitrogen-alloyed powder metallurgy tool steel and an conventional ingot cast D2 type tool steel was evaluated under lubricated sliding against ferritic stainless steel sheets using a commercial pin-on-disc (POD) and an in-house made slider-on-flat-surface (SOFS) tribotester. The investigated tool steels ranked similarly in terms of galling resistanc in both test methods. However, sliding distances to galling were longer for the SOFS equipment due to continuous sliding on new lubricated sheet surface. Best performance was demonstrated by the powder metallurgy tool steel treated to 65 HRC. Differences in friction behaviour and galling initiation were analysed on the basis of the two different working conditions, i.e. open (SOFS) and closed (POD) tribosystems. Copyright © 2012 John Wiley & Sons, Ltd.

  • 168.
    Karlsson, Patrik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Gåård, Anders
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Galling Resistance and Wear Mechanisms for Cold Work Tool Steels in Lubricated Sliding Against High Strength Stainless Steel Sheets2010In: Tribology of manufacturing processes: Proceedings of the 4th International Conference on Tribology in Manufacturing Processes (ICTMP 2010), Volume 2, Paris: Presses de l'Ecole des mines , 2010, p. 603-612Conference paper (Refereed)
  • 169.
    Karlsson, Patrik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Gåård, Anders
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Galling resistance and wear mechanisms for cold-work tool steels in lubricated sliding against high strength stainless steel sheets2012In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 286-287, p. 92-97Article in journal (Refereed)
    Abstract [en]

    Tool damage in sheet metal forming of stainless steel is of high concern for the forming industry. In the present work, ingot cast AISI D2 and advanced powder metallurgy tool steel (PM) cold-work tool steels were evaluated and ranked regarding wear mechanisms and galling resistance. Wear tests were performed using a slider-on-flat-surface (SOFS) tribometer in sliding against austenitic–ferritic (duplex) stainless steel sheets at different contact pressures in lubricated conditions. The best galling resistance was observed for the nitrogen alloyed PM tool steels. Abrasive scratching of the tool surfaces and transfer of sheet material due to adhesive wear were the main metal forming tool surface damage mechanisms. By increasing the hardness of one PM sheet metal forming tool grade, the galling resistance was enhanced.

  • 170.
    Karlsson, Patrik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Gåård, Anders
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Influence of size and distribution of hard phases in tool steels on the early stage of galling2012In: / [ed] Harald Leitner, Regina Kranz, Angelica Tremmel, 2012, p. 469-476Conference paper (Refereed)
    Abstract [en]

    In sheet metal forming processes, contact pressures are relatively high and total sliding distances are long, which demands tool steels to prevent tool damage and to resist galling. Galling is related to microscopic and macroscopic material transfer, but, the mechanisms of initiation are not thoroughly understood.

     

    To investigate galling initiation, lubricated sliding testing in the Slider-On-Flat-Surface (SOFS) tribometer was performed for ingot cast (IC) AISI D2 type and nitrogen alloyed powder metallurgy (PM) tool steel. The sheet grade was EN 1.4509 ferritic stainless steel. To reveal mechanisms in the early stages of galling initiation, transfer and accumulation of sheet material to the tool surfaces were characterized using AFM and SEM.

     

    It was found that already after a short sliding distance, transfer of sheet material occurred covering both the matrix and the hard phases. Macroscopic analysis of the contact area showed that initial material transfer and further lump growth occurred at positions corresponding to high plastic strains in the sheet material. Even though initial material transfer was observed for both tested tool steels, the sliding distance to the point where transfer and further lump formation occurred was longer for the PM tool steel. This was discussed in correlation to differences in size and distribution of the hard phases in the tool steels, which was confirmed by AFM and SEM.

  • 171.
    Karlsson, Patrik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Gåård, Anders
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Berhe-Larsson, Johanna
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Influence of tool steel hard phase orientation and shape on galling2014In: Advanced Materials Research, ISSN 1022-6680, E-ISSN 1662-8985, Vol. 966-96, p. 249-258Article in journal (Refereed)
    Abstract [en]

    Conventionally manufactured cold work tool steel is often used in sheet metal forming as die material. Due to the forging process, the as-cast network structure of carbides is broken into elongated particles. Depending on the tool cross-section, the orientation and shape of carbides in the active tool surface is different. In the present research, the influence of tool steel hard phase orientation and shape on galling was investigated. D2 type tool steel was cut in three different orientations and tested in lubricated sliding conditions against AISI 304 austenitic stainless steel. Tests were performed using a Slider-On-Flat-Surface and galling was detected by changes in friction and post-test microscopy. The lubricant was Castrol FST8 using 5 g/m2 sheet material. Results showed a strong correlation between sliding distance to galling and tool steel hard phase orientation and shape at low loads, whereas high load contact resulted in early galling in all cases. Material transfer was observed mainly to the tool steel matrix. The worst performance was observed for specimens cut so that the tool steel hard phase, M7C3 carbides in the D2 steel, were oriented along the sliding direction, which resulted in longer open tool matrix areas contacting the sheet material.

  • 172.
    Karlsson, Patrik
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Krakhmalev, Pavel
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Gåård, Anders
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Influence of work material proof stress and tool steel microstructure on galling initiation and critical contact pressure2013In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 60, p. 104-110Article in journal (Refereed)
    Abstract [en]

    EN 1.4301 (austenitic), EN 1.4509 (ferritic), EN 1.4162 (duplex) and EN 1.4310 C1000 (metastable austenitic) stainless steels were tested in lubricated sliding against an ingot cast EN X153WCrMoV12 and powder metallurgy nitrogen alloyed Uddeholm Vancron 40 tool steels to reveal critical to galling contact pressure, Pcr. The calculated Pcr were higher for steels with higher strength. At P>Pcr, due to plastic flow of sheet material, the tool is damaged substantially and wear-induced matrix damage causes rapid galling initiation. At P<Pcr, galling was not observed. The powder metallurgy tool steel was more resistant to galling against all tested stainless steels. Better performance was associated with fine and homogeneously distributed hard phases preventing intensive wear of the tool steel matrix.

  • 173.
    Kashif, Muhammad
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Design  and Manufacturing of Test Rig for Linear Electric Machine2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Volvo Technology has earlier developed a full scale prototype of linear electric machine but combustion was not controlled and there was a requirement to build the test rig. the objective was to run the prototype without using combustion.

  • 174.
    Kazymyrovych, Vitaliy
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Very high cycle fatigue of engineering materials: A literature review2009Report (Other (popular science, discussion, etc.))
    Abstract [en]

    Many engineering components reach a finite fatigue life well above 109 load cycles. Some examples of such components are found in airplanes, automobiles or high speed trains. For some materials the fatigue failures have lately been found to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. This finding contradicted the established concept of fatigue limit for these materials, which postulates that having sustained 107 load cycles the material is capable of enduring an infinite number of cycles provided that the service conditions are unchanged.

    With the development of modern ultrasonic fatigue testing equipment it became possible to experimentally establish VHCF behaviour of various materials. For most of them the existence of the fatigue limit at 107 load cycles has been proved wrong and their fatigue strength continues to decrease with increasing number of load cycles. This report describes very long life fatigue properties of most commonly used engineering materials including aluminium, titanium, nickel alloys and various types of steel.

  • 175.
    Kazymyrovych, Vitaliy
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Very high cycle fatigue of high performance steels2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Many engineering components reach a finite fatigue life well above 109 load cycles. Some examples of such components are found in airplanes, automobiles or high speed trains. For some materials the fatigue failures have lately been found to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. This finding contradicted the established concept of fatigue limit for these materials, which postulates that having sustained 107 load cycles the material is capable of enduring an infinite number of cycles provided that the service conditions are unchanged. With the development of modern ultrasonic fatigue testing equipment it became possible to experimentally establish VHCF behaviour of various materials. For most of them the existence of the fatigue limit at 107 load cycles has been proved wrong and their fatigue strength continues to decrease with increasing number of load cycles.

     

    One important group of materials used for the production of high performance components subjected to the VHCF is tool steels. This study explores the VHCF phenomenon using experimental data of ultrasonic fatigue testing of some tool steel grades. The causes and mechanisms of VHCF failures are investigated by means of high resolution scanning electron microscopy, and in relation to the existing theories of fatigue crack initiation and growth. The main type of VHCF origins in steels are slag inclusions.

    However, other microstructural defects may also initiate fatigue failure. A particular attention is paid to the fatigue crack initiation, as it has been shown that in the VHCF range crack formation consumes the majority of the total fatigue life. Understanding the driving forces for the fatigue crack initiation is a key to improve properties of components used for very long service lives. Finite element modelling of VHCF testing was added as an additional perspective to the study by enabling calculation of local stresses at the fatigue initiating defects.

     

     

  • 176.
    Kazymyrovych, Vitaliy
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Very high cycle fatigue of tool steels2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    An increasing number of engineering components are expected to have fatigue life in the range of 107 - 1010 load cycles. Some examples of such components are found in airplanes, automobiles and high speed trains. For many materials fatigue failures have lately been reported to occur well after 107 load cycles, namely in the Very High Cycle Fatigue (VHCF) range. This finding contradicts the established concept of a fatigue limit, which postulates that having sustained around 107 load cycles the material is capable of enduring an infinite number of cycles provided that the service conditions are unchanged. With the development of modern ultrasonic fatigue testing equipment it became possible to experimentally establish VHCF behaviour of various materials. For many of them the existence of the fatigue limit at 107 load cycles has been proved wrong and their fatigue strength continues to decrease with increasing number of load cycles.

    High performance steels is an important group of materials used for the components subjected to VHCF. This study explores the VHCF phenomenon using experimental data generated by ultrasonic fatigue testing of selected tool steels. The overall aim is to gain knowledge of VHCF behaviour of some common tool steel grades, while establishing a fundamental understanding of mechanisms for crack development in the very long life regime. The study demonstrates that VHCF cracks in tested steels initiate from microstructural defects like slag inclusions, large carbides or voids. It is established that VHCF life is almost exclusively spent during crack formation at below threshold stress intensity values which results in a unique for VHCF morphology on the fracture surface.

    Significant attention is devoted in the thesis to the ultrasonic fatigue testing technique, i.e. the validity and applicability of its results. FEM is employed to give an additional perspective to the study. It was used to calculate local stresses at fatigue initiating defects; examine the effect of material damping on ultrasonic stresses; and to evaluate various specimen geometries with respect to resulting stress gradient and maximum stressed material volume.

  • 177.
    Kazymyrovych, Vitaliy
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Initial crack growth in very high cycle fatigue of a hot-work tool steel2010Manuscript (preprint) (Other academic)
  • 178.
    Kazymyrovych, Vitaliy
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Burman, Christer
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    The Significance of Crack Initiation Stage in Very High Cycle Fatigue of Steels2010In: Steel Research International, ISSN 1869-344X, Vol. 81, no 4, p. 308-314Article in journal (Refereed)
  • 179.
    Kazymyrovych, Vitaliy
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Ekengren, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Stress verification and specimen design for ultrasonic fatigue testing2010Manuscript (preprint) (Other academic)
  • 180.
    Kazymyrovych, Vitaliy
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Thuvander, Fredrik
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Local stresses and material damping in very high cycle fatigue2010In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 32, p. 1669-1674Article in journal (Other academic)
  • 181. Kazymyrovych, Vitaliy
    et al.
    Ekengren, Jens
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bergström, Jens
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Burman, Christer
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Evaluation of the Giga-cycle fatigue strength crack initiation and growth in high strength H13 tool steel2007Conference paper (Refereed)
  • 182. Kifetew, G
    et al.
    Lindberg, H
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    The tensile failure phenomena on microtomed isolated and combined early- and latewood layers loaded in wet condition1996Other (Other (popular science, discussion, etc.))
  • 183. Kifetew, G
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Berglund, L A
    Lindberg, H
    Effects of drying on wood fracture surfaces from specimens tested in wet condition1998In: Wood Sci and Technology 32 1998 pp 83-94Article in journal (Refereed)
  • 184. Kifetew, Girma
    et al.
    Thuvander, Fredrik
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Berglund, L A
    Lindberg, H
    The effect of drying on wood fracture surfaces from specimens tested in wet condition1998In: Wood Science and Technology 32 1998 pp 83-94Article in journal (Refereed)
  • 185.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Användningstester Plattformen2008Report (Other academic)
  • 186.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Datorstödd undervisning med legorobotar ' nedslag i den sociala interaktionen i lärandeprocessen om legorobotar2004Conference paper (Refereed)
  • 187.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Datorstödd undervisning med legorobotar: Elevers erfarenheter2007In: Didaktisk Tidskrift, ISSN 1101-7686, Vol. 17, no 4Article in journal (Refereed)
  • 188.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Experiences of theory and practice in technical vocational education2013In: Transfer, transitions and transformations in technology education and beyond / [ed] L. Baartman & H. Middleton, 2013Chapter in book (Other academic)
  • 189.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Hur används datorn som stöd i språkundervisningen? - hinder och möjligheter2001Report (Refereed)
    Abstract [sv]

    Uppsatsen beskriver olika frågor angående datorstödd språkundervisning. Jag har intervjuat sex språklärare med utgångspunkt från följande fyra övergripande frågeområden frågeområden: användandet av datorstöd i undervisningen, praktiska möjligheter och problem, syn på elevernas inställning och syn på fortbildning. Detta för att få reda på lärarnas attityder till dessa frågor och för att få en inblick i hur användandet av datorstöd ser ut i språkundervisningen idag. Det allra viktigaste när det gäller datorstödd undervisning är att den sker med en kritisk reflektion. Olika författare, liksom respondenterna påpekar att användandet av den nya informationstekniken i undervisningen måste fylla en pedagogisk funktion och inte finnas i undervisningen för teknikens skull. Jag har kommit fram till att det finns en positiv inställning till att använda datorer bland språklärare idag. Alla lärare i min undersökning använder datorer mer eller mindre. Ibland hindras de dock i sitt användande av olika praktiska hinder som till exempel brist på resurser och bra programvara. Skolorna har olika förutsättningar för att ge lärarna möjlighet att utveckla sitt datoranvändande i undervisningen. En del lärare har endast tillgång till datorer vid enstaka tillfällen, medan det finns andra lärare som har ständig tillgång till datorer i undervisningen. Detta gör att det finns en spridning från lärare som endast använder datorn till informationssökning, till lärare som låtit datorn ersätta läroboken.

  • 190.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Legorobotar i undervisningen ' Hur ser pojkar och flickor på sitt arbete?2004In: Utbilder 1Article in journal (Other (popular science, discussion, etc.))
  • 191.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    LISA: ett teknikdidaktiskt forskningsprojekt2011Other (Other (popular science, discussion, etc.))
  • 192.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Pupils' Learning in Technical Vocational Education: Theory and Practice2010Other (Other (popular science, discussion, etc.))
  • 193.
    Kilbrink, Nina
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Teaching and Learning in Technical Vocational Education2011Other (Other academic)
  • 194.
    Kilbrink, Nina
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Bjurulf, Veronica
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Teoretiska och praktiska uppgifter i teknikundervisningen2009In: Cetis ,Norrköping, no 1, p. 1-5Article in journal (Other (popular science, discussion, etc.))
  • 195.
    Kilbrink, Nina
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bjurulf, Veronica
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Linköping university.
    Transfer of knowledge in technical vocational education: A narrative study in Swedish upper secondary school2013In: International journal of technology and design education, ISSN 0957-7572, E-ISSN 1573-1804, Vol. 23, no 3, p. 519-535Article in journal (Refereed)
    Abstract [en]

    In vocational education, teaching and learning are expected to take place in the different learning arenas; schools and workplaces. In such a dual school system, the question of transfer is vital, i.e. how to use knowledge learned in previous situations in new situations. This article is an empirical contribution to research concerning transfer, by means of results from semi-structured group interviews with teachers and supervisors who educate students in the Energy program and the Industry program in Swedish upper secondary school. The interviews were analysed by analyses of narratives. The results show four themes of transfer in the interviews: (1) transfer of basic knowledge, (2) transfer of principles and skills, (3) transfer of written materials and real life and (4) transfer of experiences. The results also show three factors that are crucial in order to create possibilities for transfer: (1) communication, (2) financial resources and (3) reflection. These factors demand close cooperation between the teachers and supervisors during the students’ vocational education.

  • 196.
    Kilbrink, Nina
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Bjurulf, Veronica
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Baartman, Liesbeth
    Faculty of Education of Utrecht University of Applied Sciences, the Netherlands.
    de Bruijn, Elly
    Utrecht University and HU University of Applied Sciences, Utrecht.
    Students’ experiences of factors for transfer in technical vocational education: A narrative study in Swedish upper secondary school2012Manuscript (preprint) (Other academic)
    Abstract [en]

    In technical vocationaleducation, carried out both in school and as workplace training, it isimportant to study how the different learning arenas contribute to the students’learning and how the students can build further on their previous knowledge andlearn for an unknown future. This research therefore provides empirical resultsfrom the learners’ point of view. This article concerns students’ experiencesof factors for transfer in the different learning arenas during technicalvocational education in Swedish upper secondary school. The research questionexamined is: What factors for transferappear in students’ narratives of learning at school and workplaces intechnical vocational education? Theory and method in this study refer tophenomenology of the life-world and narrative tradition. Interviews withstudents were conducted in two different vocational programs: the Energy andIndustry programs. Through an analysis of narratives, three different factorsfor transfer were identified: Learning atschool, Practical experiences and Holisticlearning. The results display how teachers and supervisors could supportstudents in achieving transfer, the students’ need for theoretical knowledgeabout the learning objects, as well as improving learning through variation inlearning arenas and situations.

  • 197.
    Kilbrink, Nina
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Enochsson, Ann-Britt
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Educational Studies (from 2013).
    Söderlind, Linda
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Educational Studies (from 2013).
    "As a Teacher, You Have to Take Risks": A Narrative Study on Digital Technology in Swedish Vocational Education2017Conference paper (Refereed)
  • 198.
    Kilbrink, Nina
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Segolsson, Mikael
    Pupils' learning and experiences of programming LEGO robots2005Conference paper (Refereed)
  • 199.
    Kilbrink, Nina
    et al.
    Karlstad University, Faculty of Technology and Science, Materials Science. Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Engineering.
    Söderlind, Linda
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Educational Studies (from 2013).
    Enochsson, Ann-Britt
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Educational Studies (from 2013).
    Digitala verktyg som gränsobjekt mellan skola och arbetsliv i gymnasial yrkesutbildning: Två svensklärares berättelser2016Conference paper (Refereed)
  • 200.
    Korin, Christer
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Hallbäck, Nils
    Karlstad University, Faculty of Technology and Science, Department of Mechanical and Materials Enineering.
    Barbier, Christophe
    Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering.
    Nygårds, Mikael
    KTH Royal Institute of Technology, Solid Mechanics.
    Finite Element Analysis of Hot Melt Adhesive Joints in Carton BoardManuscript (preprint) (Other (popular science, discussion, etc.))
1234567 151 - 200 of 330
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