https://www.mdu.se/

mdu.sePublications
Change search
Refine search result
1 - 24 of 24
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    af Klinteberg, Ludvig
    et al.
    KTH, Sweden.
    Sorgentone, Chiara
    KTH, Sweden.
    Tornberg, Anna-Karin
    KTH, Sweden.
    Quadrature error estimates for layer potentials evaluated near curved surfaces in three dimensions2022In: Computers and Mathematics with Applications, ISSN 0898-1221, E-ISSN 1873-7668, Vol. 111, p. 1-19Article in journal (Refereed)
    Abstract [en]

    The quadrature error associated with a regular quadrature rule for evaluation of a layer potential increases rapidly when the evaluation point approaches the surface and the integral becomes nearly singular. Error estimates are needed to determine when the accuracy is insufficient and a more costly special quadrature method should be utilized.& nbsp;The final result of this paper are such quadrature error estimates for the composite Gauss-Legendre rule and the global trapezoidal rule, when applied to evaluate layer potentials defined over smooth curved surfaces in R-3. The estimates have no unknown coefficients and can be efficiently evaluated given the discretization of the surface, invoking a local one-dimensional root-finding procedure. They are derived starting with integrals over curves, using complex analysis involving contour integrals, residue calculus and branch cuts. By complexifying the parameter plane, the theory can be used to derive estimates also for curves in R3. These results are then used in the derivation of the estimates for integrals over surfaces. In this procedure, we also obtain error estimates for layer potentials evaluated over curves in R2. Such estimates combined with a local root-finding procedure for their evaluation were earlier derived for the composite Gauss-Legendre rule for layer potentials written in complex form [4]. This is here extended to provide quadrature error estimates for both complex and real formulations of layer potentials, both for the Gauss-Legendre and the trapezoidal rule.& nbsp;Numerical examples are given to illustrate the performance of the quadrature error estimates. The estimates for integration over curves are in many cases remarkably precise, and the estimates for curved surfaces in R-3 are also sufficiently precise, with sufficiently low computational cost, to be practically useful.

  • 2.
    Bäckman, Tobias
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Ehmke, Gustav
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Utveckling av testsystem för Interface Test Adapter till Gripen ATE2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The work has been carried out as a product development project at Saab AB in Arboga, focusing on construction. Saab in Arboga develops test systems for JAS 39 Gripen, whose purpose is to verify all the contacts. This is done by using the test system, ATE.

    Before testing can begin, the wiring harness in the ITA must be verified. Currently this is done manually, and due to wiring extent, the risks of incorrect measurements are apparent. In addition to incorrect measuring, the extent of the wiring can also lead to incorrect wiring in production. These errors can result in the test system fails, which means great financial loss for the company.

    The project's aim was to develop an automated measurement process and produce a prototype, in order to verify that the ITA is correctly connected before the simulation is done. The main issue for the project has been if an automated measurement process can obtain sufficient precision to replace manual measurement.

    By analyzing the market for automated movement, a number of concepts for the overall measurement process were generated. The concepts were evaluated with decision-matrix method, as well with regard to the complexity of the required software management for each concept.

    The measurement process that was chosen based on the 3D printer and its underlying mechanics and automation. To realize the concept to a fully working prototype the process of product development was broken down in segments. This reduced the level of complexity, while it contributed to simplify optimization. In order to achieve optimum design every segment consisted of concept generation and concept evaluation.

    The construction which is the basis for the prototype is an off-the-shelf solution, and based on the parts used in the milling machine x-Carve. The overall structure is based on the milling machine, however modified to the extent that the purpose can be achieved. The choice to base the design on the X-Carve was made against the background that it harmonized well with the overall concept of measuring process, but also well with the concepts generated in the broken down segments, mentioned above. The underlying factor to the use of components which is an off-the-shelf solution to the design is a result of the project vastness and the provided time.

    The developed prototype lives up to the requirements. Empirical tests indicate that the prototype obtains sufficient precision to perform measurements. The results of the tests carried out shows that manual labor can be replaced, and therefore leads to the conclusion that the prototype proved useful.

    The prototype has some potential for development, why it is recommended to examine each segment if additional optimizations must be made.

    Download full text (pdf)
    Utveckling av testsystem för Interface Test Adapter till Gripen ATE
  • 3.
    Eriksson, Claes
    Mälardalen University, School of Innovation, Design and Engineering.
    Minimering av momentförluster i en hypoidväxel2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta projektarbete var att minska energiförlusterna i Getrag All Wheel Drives hypoidväxlar (se kapitel 7.2.3). Uppdraget bestod främst av att minska förlusterna när systemet endast driver på två hjul och de övriga hjulparen endast överför låga kraftmoment, detta förhållande benämns draggmoment. För att kunna utvärdera och peka på förbättringsområden var första steget i arbetet att lokalisera och värdera enskilda komponenter som tillförde förluster. De ingående komponenter som studerades grundligt var lager, Kuggkontakt, olja och tätningar. Värderingen av komponenternas respektive förlustbidrag erhölls genom provning och beräkningar. Provningen bestod dels av tidigare utförd provning och dels av provning utförd under arbetets gång. För beräkning av lager och tätningar användes beräkningen från lagertillverkaren SKFs egna beräkningsmodeller. Beräkning av hypoidväxelns smörjningsförluster skedde enligt ISO/TR 14179-2. Övriga beräkningar härleddes genom tribologiska formler med givna friktionskoefficienter. När ingående komponenter var värderade genom beräkningar och provning valdes de komponenter som tillförde de största förlusterna att utvecklas vidare. Vald komponent att förbättra blev lager, där förspänningen av lageranordningen mellan kronhjulsaxeln och aluminiumhus studerades. Utöver lagerförspänningen undersöktes även inverkan av oljans viskositet på lager och växel som helhet. Resultatet från konceptgenereringen resulterade i en lösning där en aluminiumring ska monteras mellan två koniska rullager på röraxeln för att bibehålla den initiala förspänningen mellan dessa lager under förhöjda temperaturer. Detta bidrar till att kunna sänka den initiala förspänningen. Genom användning av en förspänningsring av aluminium kan initial förspänning enligt analys och beräkningar sänkas från 13 kN till cirka 6 kN. Enligt beräkningar minskar momentförlusterna i lager på röraxeln då med 0,36 Nm. Det Andra konceptet var att välja en olja med lägre viskositet än dagens produktionsolja och på så vis erhålla en minskning av momentförluster. Från en kinematisk viskositet på cirka 45 mm2/s till en kinematisk viskositet på 33 mm2/s vid 80 °C minskades RDU-växelns(bakre hypoidväxel) totala förluster i lager med 0,53 Nm. Rekommendationen för fortsatt arbete blev att börja utföra grundliga tester för en olja med lägre viskositet och sedan om godkända resultat erhålls byta ut dagens växelolja. Samt att i ett senare skede genomföra provning med en förspänningsring om ytterligare förbättrad verkningsgrad önskas.

    Download full text (pdf)
    fulltext
  • 4.
    Eriksson, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering. AQ System.
    Omdimensionering av instrument för mätning av vindhastighet2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The ever-growing demand for renewable energy leads to an increased need for innovation in the green energy sector. One of the available alternatives, wind power, have seen a global increase in usage with few signs of slowing down. To increase the efficiency of individual turbines, correct placement is crucial. One technology that uses sound to find optimal locations for wind turbines is Sonic Detection and Ranging, SODAR.

    AQ system manufacture and deliver SODAR-systems internationally. The size of the system created by AQs limit the locations which the system can measure wind. Occasionally this forces measurement to be made away from the location in question which potentially reduce the efficiency of the future wind turbine. This study aims to create a concept for a smaller version of the SODAR-system manufactured by AQs. A smaller system would allow wind measurement in more remote, hard to reach locations which in turn would increase precision of the measurements and potentially efficiency of wind turbines.  

    Tools from Ulrich & Eppingers product development process was used to generate, screen, and evaluate concepts throughout the study. By changing the geometry and positioning of individual components in the system the height was reduced by 49,7% and width by 32,8%. An even smaller concept could be presented if more focus was put on the base of the product.

    Many factors that could impact the function of the product have been ignored in this study. Based on the specifications put up for this project the concept could theoretically perform as the original AQ510. Considering that relevant factors have been ignored, the function of the concept cannot be guaranteed. The tools and methods used in the product development process facilitated the development and made it possible to present a concept within the time frame. The conclusion is that, based on the specifications presented, the concept reached the goals put up for the project but to be able to guarantee the performance of the concept, measurements and tests are needed. 

    Download full text (pdf)
    fulltext
  • 5.
    Gille, Anton
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Jansson, Jesper
    Mälardalen University, School of Innovation, Design and Engineering.
    Rotationssystem till väggfixtur2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis deals with the development process for a design proposal on a rotation system. The work was performed on behalf of Husmuttern AB, whom needs a rotation system to rotate wall fixtures in the company´s future modular house factories.

    The work has been carried out with an iterative product development methodology that both addresses internal requirements of the company and external requirements from relevant regulations.

    The work´s imminent problem formulation is; how to develop a rotation system while ensuring that the construction meets the internal requirements from Humuttern AB and external regulations from the Swedish work environment authority regarding load ergonomics and machines.

    The focus in this work has, besides taking into account ergonomics and security, been to produce a concrete proposal that is to some extent close to manufacturing. This implies that standard components and standard dimensions of materials are used.

    As a validation of the developed design, FEM analyzes (Finite element method) were applied in SolidWorks where safety factors, stress distributions and deformations could be investigated for the stresses that might arise.

    The work could be completed within the deadline and delivered what the delimitations specified. The result is a rotation system that will allow ergonomic and safe operation. The work is delivered in the form of this report, which includes the described work process, calculations, drawing documentation, risk analysis and user description of the rotation system's workflow.

    Download full text (pdf)
    fulltext
  • 6.
    Holmqvist, Joacim
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Kämäräinen Bergstrand, Jimmy
    Mälardalen University, School of Innovation, Design and Engineering.
    Grid connection for electrical excavator2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 7.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Daneryd, Anders
    ABB AB, Corporate Research, Västerås, Sweden.
    Heat transfer by liquid jets impinging on a hot flat surface2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 164, no 15, p. 934-943Article in journal (Refereed)
    Abstract [en]

    Runout Table (ROT) cooling is one of the most important factors for controlling quality of hot rolled steel. ROT cooling uses large quantities of water to cool the steel plate. Optimizing heat transfer in the ROT would reduce the amount of water used, which will lower the amount of energy needed for pumping, filtering, storage and use of water. Optimization will therefore result in a direct energy saving as well as increasing the product quality.

    This study investigates heat transfer by turbulent water jets impinging on a hot flat steel plate at temperatures below the boiling point in order to understand convection heat transfer phenomena. This is an important stage that precedes the boiling and addresses the applicability of the heat transfer correlations available in the literature.

    A single axisymmetric jet and a pair of interacting jets are simulated using Computational Fluid Dynamics (CFD). The Reynolds Averaged Navier Stokes (RANS) model under steady and transient conditions and the kɛ turbulence model are used in both 2D axisymmetric and 3D simulations. We investigate the influence of the water flow rate on the jet cooling characteristics and develop a correlation for the radial position of the maximum Nusselt number based on numerical results.

    Two sets of boundary conditions – constant temperature and constant heat flux – are applied at the surface of the steel plate and evaluated. The single jet numerical results compare favourably with published data based on measurements and analytical models. The thermal performance of a two-jet system was found to be no better than a single jet because the jets were too far from each other to generate any additional thermal interaction.

  • 8.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Daneryd, Anders
    ABB, Sweden.
    Multi-Jet Impingement Cooling of a Hot Flat Steel Plate2014In: Energy Procedia, ISSN 1876-6102, Vol. 61, p. 1835-1839Article in journal (Refereed)
    Abstract [en]

    One of the most important steps to control the quality in steel hot rolling is the Runout Table (ROT) Cooling. In this investigation, the heat transfer of water jets impinging on a hot flat steel plate was studied under temperatures below the boiling point to understand the convection heat transfer phenomena which is a major step preceding the boiling. Single axisymmetric jet and a pair of interacting jets are simulated using Computational Fluid Dynamics (CFD). The RANS model under steady and transient conditions as well as the k-Ɛ turbulence model are used for both 2D axisymmetric and 3D simulations. The water flow rate influence on the jets cooling characteristics is investigated.Two sets of boundary conditions, constant temperature and constant heat flux were applied at the surface of the steel plate and evaluated. The single jet numerical results are successfully compared to published data based on measurements and analytical models. The two jets thermal performance was found to be unaffected because the jets are too far from each other to generate any additional thermal interaction.

  • 9.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Domínguez, José
    University of VIGO, Spain.
    Crespo, Alejandro
    University of VIGO, Spain.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Smoothed Particle Hydrodynamics modeling of transient conduction and convection heat transferManuscript (preprint) (Other academic)
    Abstract [en]

    Smoothed Particle Hydrodynamics (SPH) is a mesh-free particle method that has been widely used in the last years to model some complex flows. SPH was mainly used to investigate problems related to hydrodynamics and maritime engineering where heat transfer is of no importance. Thermal problems have seldom been addressed due to the limitation of the main commercial and open-source SPH codes.

    In this article, the energy equation is implemented in the SPH based open-source code DualSPHysics to solve conduction and forced convection heat transfer problems. Laminar flow cases are simulated as the first validation cases of the implemented model. The studied cases include conduction in an aluminum block, conduction in still water in a cavity, laminar water flow between two infinite parallel plates and tube bank heat exchanger. The thermal solutions obtained from SPH are benchmarked with the solutions from Finite Volume Method (FVM) and also validated using available analytical solutions. The obtained results are in good agreement with FVM and available analytical models, which combined with the advantages of the meshless approach, show the high potential for industrial heat transfer applications.

    This development is an important step towards thermal optimization of several industrial applications that can’t benefit from the conventional FVM approach due to geometry or process complexities. The demonstrated SPH simulation and visualization capabilities contribute to build the future reliable energy-saving solutions.

  • 10.
    Hosain, Md Lokman
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Fdhila, Rebei Bel
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB AB, Corporate Research, Västerås, Sweden.
    Rönnberg, Kristian
    ABB AB, Corporate Research.
    Air-Gap Flow and Thermal Analysis of Rotating Machines using CFD2017In: Energy Procedia, ISSN 1876-6102, Vol. 105, p. 5153-5159Article in journal (Refereed)
    Abstract [en]

    Thermal management of the rotating electrical machines is a very challenging area which needs appropriate solutions for each machine and operating condition. The heat is generated by the electromagnetic losses and the mechanical friction during the rotation. Computational Fluid Dynamics (CFD) is used in this study to predict and analyze the thermal performance of a rotating electrical machine where high speed rotation is coupled with small flow gaps. The investigation presented in this paper is based on a geometry used for model assessment and verification purposes. However, the approach outlined and the observations made are transferrable to other geometries. ANSYS Fluent has been used to perform CFD simulation where both the air velocity field and the temperature distribution are obtained. The results are qualitatively highly interesting to understand the thermal behavior within an electrical machine operations. The results show a periodic temperature distribution on the stator surface with similar periodic pattern for the heat transfer coefficient on the rotor surface. The simulated average heat transfer coefficient at the rotor surface is compared with the correlations from published literature with an overall good agreement.

  • 11.
    Izadi, T.
    et al.
    School of Mechanical Engineering, Shiraz University, Iran; Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Iran.
    Mehrabian, M. A.
    Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Iran.
    Sadrizadeh, Sasan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH Royal Institute of Technology, Stockholm, Sweden.
    Olofsson, U.
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Abouali, O.
    School of Mechanical Engineering, Shiraz University, Iran; KTH Royal Institute of Technology, Stockholm, Sweden.
    The effect of ventilation system with and without under-platform exhaust on the concentration of braking micro-particles inside the subway system2022In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 128, article id 104638Article in journal (Refereed)
    Abstract [en]

    Thermal comfort has been the main target of the ventilation in subway systems. However, pollutant concentration and aerosol dispersion could be the leading health issues in underground metro stations. This study numerically simulated a train movement inside a subway system using the Dynamic Mesh Technique for a 3-D computational domain consisting of four stations and connecting tunnels. The effects of both the ventilation system and the train-induced fluid flow inside the subway system were investigated. Then, the particle generation and dispersion due to train braking are considered, and the impact of the ventilation system on reducing the particle concentration inside the station was investigated. It is shown that the airflow inside the subway system is entirely affected by the piston effect. The airflow generated by the train movement is much higher than that generated by the operation of the ventilation system when only one train passes through the tunnel. The results show that the ventilation system, consisting of the supply and exhaust fans inside the tunnel and supply grilles inside the platform, can reduce the particle concentration by half, except for the platform beside the stopped train when the train enters the station and during half of the train stop time. The other design concept demonstrates that the under-platform exhaust system considerably reduces the concentration of the particles released by the train braking system on the trackside platform.

  • 12.
    Jaber, André
    Mälardalen University, School of Innovation, Design and Engineering.
    Concept design of an ultra-light industrial robot2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use of industrial robots are increasing in areas such as food, consumer goods, wood, plastics and electronics, but is still mostly concentrated in the automotive industry. A problem is that workstations in smaller and medium sized companies that produce small batches of products don’t get productive enough by having a permanently placed industrial robot. A solution could be a lightweight robot that is adaptable to the product need. It would have lower moving mass that will reduce the power need and result in “greener” robotics.

    The aim of this project has been to develop a concept of a lightweight robot using lightweight materials such as aluminum and carbon fiber together with a newly developed servo actuator prototype.

    The main problem was how to place the servo actuators, to create a wrist that would be thin and durable, while keeping performance as an ABB IRB 2600 robotic wrist. The wrist also needs to be constructed for cabling to run through on the inside. It is expensive to change cables and therefore the designing to reduce the friction on cable, is crucial to increase time between maintenance.

    A concept generation was performed based on the function analysis, the QFD and the specifications of requirements that had been established. From the concept generation, twenty-four sustainable concepts divided into four groups (representing an individual part of the whole concept) were evaluated.  From the evaluations a few concepts from each group was chosen to do a more thorough investigation on. The best concepts from each group were then merged into a final concept that was taken for further development. 

    The chosen concept was more detailed designed, which seemingly did not fulfill the requirements as good as I had hoped, but during the further development a small change in the concept helped with fulfilling those demands. To evaluate possible component failure, an FMEA was established.

    The chosen concept of this thesis could fulfill the problems of designing a lightweight arm while keeping the same performance as the IRB 2600 robotic arm. This was realized by using the newly developed servo actuator together with the design that resulted from the implemented design process. The chosen concept has a thin wrist, with smooth passages for cables to run through keeping costs down. The robotic wrist needs more thorough analysis and testing, and I recommend that a mechanical prototype is made to test the movements of the robot.

    Download full text (pdf)
    fulltext
  • 13.
    Jansson, Christoffer
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Press-sekvens för lagerringar2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is the result of a thesis work in mechanichal engineering performed at Volvo GroupTrucks Operations, Powertrain productions in Köping by the student Christoffer Jansson. Thework of 15 ECTS credits is conducted over a 20 week period at half speed equivalent to 400working hours.The background to the work is the desire to improve a workstation where the transmissions tothe IPS2/3 and IPS15 are assembled. The problem on the workstation is that the workers areperforming non value-added activities (NVAA) and it is of interest that one would examine thepossibility of how to squeeze two bearing rings in the same sequence. The aim is thus todevelop a suggestion of improvement for the bearing pressing method on the assembly line.The issue the thesis work is based on is: How does one manage to press together two bearingrings in the same sequence into a particular component? & How can one improve theergonomic circumstances on the workstation?To be able to perform this work, a case study based on the product development processaccording to Ulrich and Eppinger (2012) has been made. Product development tools are used tofacilitate the work of the student. Including Gantt chart, Pugh's analysis and functional analysis.The result of the work is a modification of the existing working table where the bearing ringsare pressed into the middle gear housing. The solution consists of a steel plate that rests on fivesprings which dampen the weight of the middle gear housing. The middle gear housing is thecomponent in which the bearing rings are pressed in. There are 5 guiding rods that are mountedon the steel plate, one for each spring, which has the function to keep the steel plate stablewhen the middle gear housing is set on top. These guiding rods are in turn controlled bybushings which serve to reduce friction. The bushings are standard components that aremounted into a component called the bushing holder, which is a component that is screwed intothe table.The new working process the solution provides eliminates the previous NVAA that has been onthe station before and allows the worker to press two bearing rings into the middle gearinghouse in the same sequence. The ergonomic circumstances have also been improved due to theelimination of the worker having to rotate the heavy middle gearing house 180 degrees. Thesolution thus meets the demands made in the report and solves the problems identified.

    Download full text (pdf)
    fulltext
  • 14.
    Johansson, Jimmy
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Kellokumpu, Petra
    Mälardalen University, School of Innovation, Design and Engineering.
    Klamningskoncept för kablage på motor: Examensarbete, produktutveckling - konstruktion2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts på initiativ av Scania CV AB. Scania är en världsledande tillverkare av tunga lastbilar, bussar och industri- och marinmotorer. Konstruktionsgruppen inom Scania som detta examensarbete utfördes vid är benämnd NMKA och är en del av avdelningen NM – Engine development som bedriver forskning & utveckling av Scania motorer.

    Denna avhandling inom produktutveckling tjänar syftet som slutgiltigt examinationsmoment för civilingenjörsprogrammet Innovation och produktdesign på Mälardalens högskola. Arbetet har utgått ifrån en metod för produktutveckling som lärs ut i samband med utbildningen.

    Uppdraget har baserats på frågeställningen att utveckla ett robust klamningskoncept för kablage på motor, som uppfyller de ergonomiska och konstruktionsmässiga krav som Scania ställer på sina artiklar. Klamningskonceptet ska därmed möjliggöra säker infästning av lättare kabel, rör och slang i flera olika dimensioner. Samt även kunna upprätthålla denna funktion under de stränga förhållanden som råder i miljön kring motor. Vilket ställer höga krav på brukstemperatur, kemikaliebeständighet, egenfrekvens och livslängd.

    Det befintliga infästningselement som används idag i aktuella applikationsområden uppfyller inte Scanias ergonomiska krav och måste därför fasas ut och ersättas. En begränsning som medföljer är att det nya klamningskonceptets artikelpris måste ligga inom samma prisspektrum som sin föregångare.

    En stor del av Scanias verksamhet är belägen i Södertälje, däribland produktionslinan för montering av raka motorer till lastbil, buss och marina applikationer. Monteringen av motorkomponenter sker i hög grad manuellt, vilket medför repetitiva och ibland ergonomiskt påfrestande moment för montörerna. Scania värnar om sina anställda och prioriterar deras hälsa högt så att dem kan känna sig trygga i sin arbetsmiljö och fullfölja ett långt arbetsliv. Att ta fram och utveckla nya produktlösningar som minimerar eller motverkar riskerna för skador är därför en naturlig del av förbättringsarbetet. Samt en bidragande faktor till initiativet bakom formuleringen till detta examensarbete.

    Detta examensarbete har resulterat i ett förslag på ett klamningskoncept som har lägre artikelkostnad, är mer ergonomisk att montera och har kortare monteringstid. Klamningskonceptet är avsett enbart för applikationsområden med lättare rör och kablage, med infästning för M6-skruvförband. På det testade applikationsområdet avluftningsnätet innebär gruppens klamningskoncept en årlig kostnadsreducering på 50 % relativt det nuvarande infästningselementet.

    Download full text (pdf)
    fulltext
  • 15.
    Kabroo, Carl Gustaf
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Willenius, Robert
    Mälardalen University, School of Innovation, Design and Engineering.
    Produktionsoptimering av elektromagnetiska omrörare - "ORD 43P" och "EM Stabilizer"2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The thesis in product development – design was carried out between February and June 2013 and includes 15 credits (C-level), and is the final course of the Bachelor Program in Engineering, Innovation and Product Design. 

    The thesis dealt with the problem of adaptation to production and cost optimization of two pieces of electromagnetic stirrers at the company ABB, Process Automation, Metallurgy in Västerås. After contact with the supervisor from ABB, Jan-Erik Eriksson, the project work commenced to adapt the manufacturing design of the product ORD 43P and EM Stabilizer.

    To achieve cost-optimized production and production adapted design, the authors applied the following product development tools: Design for Cost, Design for Manufacture and Design for Assembly. To verify that the design was optimal, but also that it did not break during stress, the authors used the computer based module finite element method of the CAD program SolidWorks. 

    The selection of components was based on the component’s price per kilo. 

    To select the optimum material, that is high strength and affordable, the authors used the material database software CES EduPack. The materials selected from CES EduPack could not be found by the authors as standard material at the market. Therefore, the authors changed strategy to compare and select materials based on market research of standard materials with suppliers.

    The components of ORD 43P were optimized in terms of design in comparison with existing components coil bracket and insulation boards. They were also cost reduced significantly. The component frame base was examined briefly. 

    Through product development the components coil bracket, insulating boards and frame base the total cost of ORD 43P was reduced by 2,47 %. 

    The authors found that the total cost of ORD 43P could be reduced between 10-25 % as many of its components are oversized and made ​​of more expensive materials than needed. 

    The components of EM Stabilizer, cover and pneumatic hose, were designed with optimum design and was cost reduced.Through product development the components cover and pneumatic hose the costs of EM stabilizer were reduced by 1,3 %. 

    The authors assume that the costs of the EM Stabilizer can be reduced, because it is relatively new at the market. ABB want to ensure that the product reach its guaranteed life by over-sizing many of the components of the product and use more expensive material than necessary.

    Download full text (pdf)
    Produktionsoptimering av elektromagnetiska omrörare
  • 16.
    Kumm, Maria
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ingason, Haukur
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. SP Tech Res Inst Sweden, Boras, Sweden.
    Entrainment in a free jet generated by Positive Pressure Ventilator2014In: Fire technology, ISSN 0015-2684, E-ISSN 1572-8099, no 6, p. 1499-1515Article in journal (Refereed)
    Abstract [en]

    Results of a simple flow model to describe the entrainment into the air cone created by a positive pressure ventilator (PPV) fan are compared to experimental data. Velocity profiles measured in the air cone of a conventional PPV ventilator are used. The entrainment coefficient and the cone angle were determined for the fan investigated. The correspondence between calculated and measured values is discussed and disparities explained. The findings from the tests are turned into practical guidance for the fire brigade and the advantages and limitations of the simplified model are discussed.

  • 17.
    Larsson, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering.
    Tiltbar reverse trike: Utveckling och prototyptillverkning2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I denna rapport presenteras utveckling och prototyptillverkning av ramen och tiltfunktionen till en tiltbar reverse trike. En reverse trike är ett fordon med ett bakhjul och två framhjul. Bakhjulet är det drivande hjulet medan de två framhjulen är de styrande.

    Ett personligt intresse har alltid funnits för cyklar och cykelliknande fordon med fler än två hjul. I stort sett samtliga cyklar av den typen som finns kommersiellt tillgängliga idag använder sig utav en stel ram med begränsad fjädring på respektive hjul. Problemet med dessa är att de inte ger samma inlevelse vid färd som exempelvis en vanlig tvåhjulig cykel eller en motorcykel där fordonet kan lutas vid kurvtagning för att bättre utnyttja vikt och tyngdpunkt för att inte tippa. Det är den känslan som saknas hos dagens cykelliknande fordon.

    Projektet är utfört som ett examensarbete inom Produktutveckling – konstruktion under våren 2014 på Mälardalens högskola och är på D-nivå (30 högskolepoäng).

    Frågeställningarna som ligger till grund för projektet är:

    1. Vilka regler gäller för ett pedallöst cykelklassat fordon?

    2. Vilket material bör användas för att få en lätt och hållbar konstruktion?

    3. Vilken lösning lämpar sig bäst för fjädring?

    4. Hur kan ramen konstrueras för att möjliggöra tiltning?

    Projektet inleds med en informationsinhämtning där lagar och regler kring den typen av fordon undersöks och problemscenarion tas fram. Resultaten ligger sedan till grund för genereringsprocessen som avslutas med en konceptrealisering och prototyptillverkning. Under arbetet har funktionslösningar analyserats och med beräkningar har hållfastheten på prototypen fastställts.

    Det slutliga konceptet är en ram för en rent eldriven cykel av typen reverse trike, det vill säga att cykeln har ett bakhjul och två stycken framhjul. Den är rent eldriven och det innebär att fordonet inte har pedaler för framdrivning utan att den endast drivs av en elmotor.

    Det som skiljer detta koncept från befintliga produkter och som dessutom är huvudsyftet med konceptet och gör det unikt, är möjligheten att tilta som idag är i stort sett obefintligt hos konkurrenterna. Det har inte kunnat utföras några tester då prototypen inte hann färdigställas. Konceptet uppfyller endast genom teoretisk analys de krav som har ställts.

    Prototypen tillverkas i aluminiumprofiler av typen EN6063-T6, Aluminiumplåt av typen EN6082-T6 samt ett antal detaljer i nylon och stål. Konceptet uppfyller kraven från Transporstyrelsen vilket gör den laglig att framföras i trafik enligt svensk lag.

    Download full text (pdf)
    fulltext
  • 18.
    Liu, Z
    et al.
    College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, China.
    Liu, Z.
    College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, China; Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Liu, G.
    Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yang, Xiaohu
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Institute of Building Environment and Sustainability Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Melting assessment on the effect of nonuniform Y-shaped fin upon solid–liquid phase change in a thermal storage tank2022In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 321, article id 119330Article in journal (Refereed)
    Abstract [en]

    This study provides an alternative solution to the improvement on solid–liquid phase change by designing a Y-shaped fin in a nonuniform pattern along the gravity direction. A numerical model is established and validated through the present measurement and data in literature. Six cases with different Y-shaped fins and locations are designed and compared to the original straight fin case. Thermal assessments on the melting fraction, temperature field, velocity distribution, and uniformity for melting are made. Results demonstrate that the nonuniform melting features caused by the local natural convection are significantly eliminated by the novel nonuniform fin structure. The time required for melting the lower PCM is found to occupy more than 50% of the completely melting time. The accurate local heat transfer enhancement measures (bottom enhancement) are conducive to markedly reduce the full melting time by 21.5%, compared to the uniform fin pattern. Upon using finned thermal storage tank for a mobilized thermal storage truck (bare tube tank), the initial investment increases by 44.9% but the profit increases by 393.6% and the payback period reduces by 69.2%. The use of fin tube in heat storage tank can quickly obtain higher returns based on a small increase in initial investment. This work provides new insights into the understandings of the transient phase change process and the strategies for guiding the design for thermal energy storage tank. 

  • 19.
    Skog, Axel
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Utveckling av en mindre borrigg2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is a bachelor thesis at Mälardalens University in Eskilstuna on the behalf of Scandinavian pile Driving AB in Sala.Scandinavian pile Driving AB is a relatively small company with high competitiveness that develops and manufactures drilling rigs and foundation mast in its factory in Sala.This report has investigated the development possibilities of Scandinavian Pile Driving AB's machine MD40, which is a smaller drilling rig which is usually used in smaller and special drilling operations. Where the company asks to find out what requirements the market demands and design suggestions on how their new machine can be designed.The work process in this report has strived to follow the six phases of the product development process presented in the book "Product Design and Development" by Karl T. Ulrich and Steven D. Eppinger up to and including Phase 3. Thereby, the work has completed market research in the form of benchmarking of competing companies drilling rigs and interviewing users of the MD40 drilling rig.With this reason, the work could have resulted in 11 concepts where one of the concepts has been transferred to a 3D CAD model with associated drawings. The goal of development has been to minimize the total volumes of the machine, maximize mobility and space controlsystem and make it as stable as possible.

    Download full text (pdf)
    fulltext
  • 20.
    Soibam, Jerol
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Aslanidou, Ioanna
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bel Fdhila, Rebei
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Hitachi ABB Power Grids, Västerås, Sweden.
    A Data-Driven Approach for the Prediction of Subcooled Boiling Heat Transfer2020In: Proceedings of The 61st SIMS Conference on Simulation and Modelling SIMS 2020, 2020, p. 435-442Conference paper (Other academic)
    Abstract [en]

    In subcooled flow boiling, heat transfer mechanism involves phase change between liquid phase to the vapour phase. During this phase change, a large amount of energy is transferred, and it is one of the most effective heat transfer methods. Subcooled boiling heat transfer is an attractive trend for industrial applications such as cooling electronic components, supercomputers, nuclear industry, etc. Due to its wide variety of applications for thermal management, there is an increasing demand for a faster and more accurate way of modelling. 

    In this work, a supervised deep neural network has been implemented to study the boiling heat transfer in subcooled flow boiling heat transfer. The proposed method considers the near local flow behaviour to predict wall temperature and void fraction of a sub-cooled mini-channel. The input of the network consists of pressure gradients, momentum convection, energy con- vection, turbulent viscosity, liquid and gas velocities, and surface information. The output of the model is based on the quantities of interest in a boiling system i.e. wall temperature and void fraction. The network is trained from the results obtained from numerical simulations, and the model is used to reproduce the quantities of interest for interpolation and extrapolation datasets. To create an agile and robust deep neural network model, state-of-the-art methods have been implemented in the network to avoid the overfitting issue of the model. The results obtained from the deep neural network model shows a good agreement with the numerical data, the model has a maximum relative error of 0.5 % while predicting the temperature field, and for void fraction, it has approximately 5 % relative error in interpolation data and a maximum 10 % relative error for the extrapolation datasets. 

    Download full text (pdf)
    SIMS2020_JS
  • 21.
    Su, Keng
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Danilov, Sophie
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of the XDT - A new Machine Concept2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report of a master thesis is performed by two students at Mälardalen University, Sophie Danilov and Keng Su, at Volvo Construction Equipment in Eskilstuna.

    The assignment was to continue the development of a new machine concept for the Department of Advanced Engineering – Emerging Technologies.

    Due to this projects delicacy, the report is confidential and therefor only this abstract is official.

  • 22.
    Tabatabaee Ghomi, Mohammad
    Mälardalen University, School of Sustainable Development of Society and Technology.
    MODELLING AND SIMULATION OF ELASTIC & PLASTIC BEHAVIOUR OF PROPAGATING IMPACT WAVE: Impact- echo and Explosive welding process development2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A force that is applied dynamically in a short period of time is called an impact force (shock wave). Due to the concentrated application of force on a small area in a fraction of a second, unique applications have emerged that other types of loadings are not capable of performing. Explosions, an impact of a hammer, impact of waves on a shore wall, or the collision of two automobiles are examples where impact waves occur. In this research the effects of impact on solid materials and the motion of stress waves due to the impact are studied and some of their industrial applications are described.

     

    The primary objective of this work is further development of some elastic and plastic impact wave methods, aiming to reduce the energy consumption of explosive welding (EXW) as well as the cost of NDT technologies. Many numerical simulations and a vast amount of experimental work were employed to reach this goal.

     

    The impact wave creates elastic deformations that move the particles of the body. In this research we focused on dimensional measurement by calculating the time of wave travel between the source of energy and a discontinuity in the part studied. The impact echo (IE) method can be used for determining the location and extent of all kinds of flaws, such as cracks, de-lamination, holes and de-bonding in concrete structures, columns and hollow cylinders with different cross-sections and materials. In the present study, simulation of the impact-echo method was carried out numerically using direct and indirect methods. In the direct method a steel ball directly impacts on the upper surface of a concrete plate-like structure, whereas in the indirect method the impact impulse transmits to the concrete plate via a steel bar, in order to adapt the method for situations where there is no access to the plate being measured. In each method a two-dimensional finite element analysis (in axisymmetric geometry) was performed for the thickness measurement of concrete plates using the LS-DYNA program. Numerical results are presented for different values of plate thickness and different projectile speeds for both the direct and the indirect method and the indirect results are validated by comparison with the results obtained by the direct method. The method was validated against experimental measurements.

     

    A high energy impact wave produces plastic deformations in metals. In this research explosive welding was studied as an application of high energy impact waves. A new method for joining different, non-compatible metals (Al and Cu-based materials) was introduced. This method may be extended for use in offshore applications. Many 3-D numerical simulations were performed using the ABAQUS explicit commercial software. The model was validated against experimental measurements.

     

    The outcome of this research work could be summarized as follows:

    a)  Introducing an indirect IE method in NDT technology for thickness measurement in particularly inaccessible structures.

    b)  Introducing a new, grooved method in EXW technology to join surfaces made of different materials, in particular Al-Cu joints.

    The results could be employed to reduce the energy consumption and cost associated with EXW and IE technologies. The methodology can be used in many other applications in all kinds of process industries.

    Download full text (pdf)
    fulltext
  • 23.
    Vakilha, M.
    et al.
    Mechanical Engineering Department, Université de Sherbrooke, Sherbrooke, QC, Canada.
    Amiri, L.
    Mechanical Engineering Department, Université de Sherbrooke, Sherbrooke, QC, Canada.
    Mesgarpour, Mehrdad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Safdari Shadloo, M.
    Mechanical Engineering Department, Université de Sherbrooke, Sherbrooke, QC, Canada; INSA Rouen Normandie, Univ Rouen Normandie, CNRS, Normandie Univ, Rouen, France; Institut Universitaire de France, Paris, France.
    A modified continuum surface force (M-CSF) model for two-phase flow problems in smoothed particle hydrodynamics2024In: International Journal of Modelling and Simulation, ISSN 0228-6203Article in journal (Refereed)
    Abstract [en]

    This work proposes a modified interfacial tension model based on the continuum surface force (M-CSF) in the context of smoothed particle hydrodynamics. This correction aims to enhance computational stability, improve force evaluation precision, and increase symmetry around the interface. Several two-phase flow benchmarks are solved using both the conventional and proposed CSF models, and the results are compared with each other and with the available literature. The results indicate that the modified model can efficiently increase the force evaluation accuracy in the pressure field at the interface. For instance, the relative error in pressure calculation using the proposed and conventional CSF models is 0.05% and 3.5%, respectively, when compared to the analytical solution, with both models having the same particle resolutions for the droplet deformation problem. In predicting the critical surface tension for hydrodynamic instabilities, such as the Rayleigh-Taylor instability, the M-CSF methodology exhibits much better alignment with existing theories, showing less than 5% deviation, while conventionally used CSF models can deviate up to 15% for the same problem. These findings confirm the superiority of the proposed methodology in evaluating interfacial forces, even in complex hydrodynamic instabilities.

  • 24.
    Zhang, Tingshen
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, 610031, China; Yibin Research Institute, Southwest Jiaotong University, Yibin, 640000, China .
    Cao, H.
    Yibin Research Institute, Southwest Jiaotong University, Yibin, 640000, China.
    Zhang, Z.
    Yibin Research Institute, Southwest Jiaotong University, Yibin, 640000, China.
    Kong, W.
    Yibin Research Institute, Southwest Jiaotong University, Yibin, 640000, China.
    Kong, L.
    Yibin Research Institute, Southwest Jiaotong University, Yibin, 640000, China.
    Liu, J.
    School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Building Environment and Energy Engineering, Hong Kong Polytechnic University, Hong Kong.
    A variable damping vibration energy harvester based on Half-Wave flywheeling effect for freight railways2023In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 200, article id 110611Article in journal (Refereed)
    Abstract [en]

    The vibrational energy, often considered a negative factor, is abundant in everyday life. Especially in railway systems, the negatively impacted track vibrations resulting from moving trains can be captured to provide a practical power supply solution for wireless sensor networks. This paper proposed a variable damping vibration energy harvester with a half-wave flywheel for a freight train-based railway. A double-sided rack as the input member converts the track vibration into the opposite rotation of the two pinions, which are then transmitted to the two parallel shafts respectively. According to the work characteristics of the one-way bearing, the upper and lower vibrations can be collected separately and output a one-way rotation to the generator module. The proposed harvester with a half-wave flywheel features a larger damping force for vibration reduction during the downward track vibration and a smaller damping force conducive to returning the track's original state during the upward track vibration. The experimental results achieve a maximum output power of 10.247 W and a maximum mechanical efficiency of 74.49%. Both simulations and experiments have verified that the proposed system with a half-wave flywheel can increase the damping force in the vibration reduction process and reduce the damping force in the reset process, which is characteristic of improving its power generation performance with a good vibration reduction effect. The VEH with the half-wave flywheel achieved an average power of 5.321 W at the train speed of 90 km/h under random vibration testing, which verifies the feasibility of self-powered wireless sensor networks in railway environments. 

1 - 24 of 24
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf