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  • 51.
    Blomgren, Anton
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Konceptförslag på tunnelkonsol med mugghållare och förvaring2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background to this project is that Volvo Cars AB wants to give the customer more opportunities to store things in their cars. Today, the customer brings many different objects into their cars, for example cups, bottles and cell phones. The customer would like to have the ability to store these things in a practical and easily accessible way.

    Volvo Cars AB wanted new ideas for the centre stack with focus on the cup holder and storage facilities. The centre stack is the component that are located between the driver's seat and passenger seat of the car where the armrest and gear lever are. The concepts that were developed shall make the centre stack into a more efficient and smarter way to store things. The project was to develop a cup holder that can be used as a cup holder and at the same time as a storage space, a dual functional cup holder. It was also included in the task to find other storage facilities that can improve the centre stack.

    In this project a product development process has been used to produce concepts for the centre stack. By analysing the assignment and the use of brainstorming about 70 ideas was produced. They were reduced to 24 through a discussion with the supervisor at Volvo. Then a discussions was conducted with engineers at Volvo from the interior department, that resulted in eleven concepts remained to be developed further. From these eleven concepts three end concepts were chosen with the help of a decision matrix.

    The three end concepts were two dual functional cup holders and one bottle holder. All these end concepts are easy to apply to the centre stack and are also easy for the customer to use.

  • 52.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Supporting Tools for Operator in Robot Collaborative Mode2015In: Procedia Manufacturing, ISSN 2351-9789, Vol. 3, p. 409-416Article in journal (Refereed)
    Abstract [en]

    Making use of robot automation for customized products put high demand not only on the robot but on the efficiency, simplicity and flexibility to actually deploy and use robots in manufacturing stations and production lines in short batches and low volume production. Hence, market oriented product development and production requires more products to be developed and offered in less time than before, and produced for the market with more customizable options. The role of the operator is in this context an important factor and tools are needed to support the operator for highly efficient and flexible production. In this paper, the development and study of supporting tools for operators is presented. A demonstrator has been built for robotic nailing, screwing and manipulation operation in producing scaled down gable wall elements in wood for a family house. Issues raised to support the operator included automatic programming and generating relevant information for the operator for the deployment procedure to prepare for production. During production, different concepts of safety system to support collaboration mode between the operator and the robot was developed and studied. Wearable devices was used for the operator to access the information generated and different safety configurations were developed and evaluated. The baseline for this work has been to identify industrial use cases which has a clear need for automation as well as collaboration between operator(s) and robot(s). Work scenarios were discussed and analyzed with industrial partners and it was concluded that, in addition to the deployment tools, a smart safety system which is able to detect and react on humans entering the robot system work area is needed. This should support for efficient production and less downtime for both automatic mode and collaboration mode. The benefit of operator – robot collaboration is clearly shown as well as the need for supporting tools.

  • 53.
    Bolmsjö, Gunnar
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Bennulf, Mattias
    University West, Department of Engineering Science, Division of Production System.
    Zhang, Xiaoxiao
    University West, Department of Engineering Science, Division of Production System.
    Safety System for Industrial Robots to Support Collaboration2016In: Advances in Ergonomics of Manufacturing: Managing the Enterprise of the Future. Proceedings of the AHFE 2016 International Conference on Human Aspects of Advanced Manufacturing, July 27-31, 2016, Walt Disney World®, Florida, USA / [ed] Christopher Schlick, Stefan Trzcieliński, Springer International Publishing , 2016, p. 253-265Chapter in book (Refereed)
    Abstract [en]

    The ongoing trend towards manufacturing of customized products generates an increased demand on highly efficient work methods to manage product variants through flexible automation. Adopting robots for automation is not always feasible in low batch production. However, the combination of humans together with robots performing tasks in collaboration provides a complementary mix of skill and creativity of humans, and precision and strength of robots which support flexible production in small series down to one-off production. Through this, collaboration can be used with implications on reconfiguration and production. In this paper, the focus and study is on designing safety for efficient collaboration operator—robot in selected work task scenarios. The recently published ISO/TS 15066:2016 describing collaboration between operator and robot is in this context an important document for development and implementation of robotic systems designed for collaboration between operator and robot.

  • 54.
    Bonilla Hernández, Ana Esther
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Analysis and direct optimization of cutting tool utilization in CAM2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The search for increased productivity and cost reduction in machining can be interpreted as the desire to increase the material removal rate, MRR, and maximize the cutting tool utilization. The CNC process is complex and involves numerous limitations and parameters, ranging from tolerances to machinability. A well-managed preparation process creates the foundations for achieving a reduction in manufacturing errors and machining time. Along the preparation process of the NC-program, two different studies have been conducted and are presented in this thesis. One study examined the CAM programming preparation process from the Lean perspective. The other study includes an evaluation of how the cutting tools are used in terms of MRR and tool utilization.

    The material removal rate is defined as the product of three variables, namely the cutting speed, the feed and the depth of cut, which all constitute the cutting data. Tool life is the amount of time that a cutting tool can be used and is mainly dependent on the same variables. Two different combinations of cutting data might provide the same MRR, however the tool life will be different. Thereby the difficulty is to select the cutting data to maximize both MRR and cutting tool utilization. A model for the analysis and efficient selection of cutting data for maximal MRR and maximal tool utilization has been developed and is presented. The presented model shortens the time dedicated to the optimized cutting data selection and the needed iterations along the program development.

  • 55.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Analysis method for pulsed thermography based on an analytical solution of the heat equation2014Article in journal (Refereed)
    Abstract [en]

    An analytical solution to the heat equation is presented, using a simplified physical model of pulsed thermography. This solution was compared to experimental data and showed good correlation, with r=0.97. An analysis method for sizing and determining the depth of a defect was developed using this analytical solution. The shape of the defect was estimated using deconvolution. Results from thermography tests on flat bottom holes show the possibilities of the method to determine the size, shape and depth of the defect, if the physical properties of the material are known.

  • 56.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Surface crack detection in welds using thermography2013In: NDT & E international, ISSN 0963-8695, E-ISSN 1879-1174, Vol. 57, p. 69-73Article in journal (Refereed)
    Abstract [en]

    Thermography is today used within non-destructive testing for detecting several different types of defects. The possibility for using thermography for detecting surface cracks in welded metal plates has here been investigated. During testing the weld is illuminated using a high power infrared light source. Due to surface cracks acting like black bodies, they will absorb more energy than the surrounding metal and can be identified as a warmer area when imaged using an infrared camera. Notches as well as real longitudinal cold cracks in a weld are investigated using the presented method. The results show that thermography is promising as a method for detection cracks open to the surface.

  • 57.
    Broberg, Patrik
    University West, Department of Engineering Science, Division of Process and Product Development.
    Towards Automation of Non-Destructive Testing of Welds2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    All welding processes can give rise to defects that will weaken the joint and can lead to failure of the welded structure. Because of this, non-destructive testing (NDT) of welds have become increasingly important to ensure the structural integrity when the material becomes thinner and stronger and welds become smaller; all to reduce weight in order to save material and reduce emissions due to lighter constructions.

    Several NDT methods exists for testing welds and they all have their advantages and disadvantages when it comes to the types and sizes of defects that are detectable, but also in the ability to automate the method. Several methods were compared using common weld defects to determine which method or methods were best suited for automated NDT of welds. The methods compared were radiography, phased array ultrasound, eddy current, thermography and shearography. Phased array ultrasound was deemed most suitable for detecting the weld defects used in the comparison and for automation and was therefore chosen to be used in the continuation of this work. Thermography was shown to be useful for detecting surface defects; something not easily detected using ultrasound. A combination of these techniques will be able to find most weld defects of interest.

    Automation of NDT can be split into two separate areas; mechanisation of the testing and automation of the analysis, both presenting their own difficulties. The problem of mechanising the testing has been solved for simple geometries but for more general welds it will require a more advance system using an industrial robot or similar. Automation of the analysis of phased array ultrasound data consists of detection, sizing, positioning and classification of defects. There are several problems to solve before a completely automatic analysis can be made, including positioning of the data, improving signal quality, segmenting the images and classifying the defects. As a step on the way towards positioning of the data, and thereby easing the analysis, the phase of the signal was studied. It was shown that the phase can be used for finding corners in the image and will also improve the ability to position the corner as compared to using the amplitude of the signal. Further work will have to be done to improve the signal in order to reliably analyse the data automatically.

  • 58.
    Broberg, Patrik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Garner, Simon
    TWI.
    Sizing of subsurface defects in thin walls using laser ultrasonics2014Article in journal (Refereed)
    Abstract [en]

    Laser ultrasonics is a non-destructive testing technique where a focused laser is used for generating an ultrasound pulse and a second laser is used for detection. This ultrasound pulse is used for detecting surface or near surface defects. A defect will not only reflect the incoming surface wave, but also alter the frequency contents of the transmitted wave. When the detection laser was scanned along the surface, changes in frequency contents of the sound pulse were detected and could be analysed to give information about the diameter of the defect.

  • 59.
    Broberg, Patrik
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Production System.
    Analysis algorithm for surface crack detection by thermography with UV light excitation2016In: Quantitative InfraRed Thermography 2016: Abstracts / [ed] Kaczmarek, M. & Bujnowski, A., Gdańsk, Poland: Publishing Gdańsk University of Technology , 2016, p. 144-149Conference paper (Refereed)
    Abstract [en]

    Surface crack defects can be detected by IR thermograpgy due to the high absorption of energy within the crack cavity. It is often difficult to detect the defect in the raw data, since the signal easily drowns in the background. It is therefore important to have good analysis algorithms that can reduce the background and enhance the defect. Here an analysis algorithm is presented which significantly increases the signal to noise ratio of the defects and reduces the image sequence from the camera to one image.

  • 60.
    Broberg, Patrik
    et al.
    University West, Department of Engineering Science, Division of Process and Product Development.
    Sjödahl, Mikael
    University West, Department of Engineering Science.
    Runnemalm, Anna
    University West, Department of Engineering Science, Division of Process and Product Development.
    Comparison of NDT-methods for automatic inspection of weld defects2015In: International journal of materials & product technology, ISSN 0268-1900, E-ISSN 1741-5209, Vol. 50, no 1, p. 1-21Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to investigate different NDT-methods for weld inspection in an objective manner. Test objects are produced with known variation of flaws: internal pores, surface and internal cracks, toe radius and weld depth. The NDT-methods compared are: phased array ultrasound, radiography, eddy current, thermography and shearography. The results show that radiography is the better method for volumetric defects in thin plates while ultrasound is better for flat defects and thicker, non-flat plates. Thermography was shown to have a good ability of detecting surface defects. A combination of ultrasound and thermography results in a detection of all the non-geometrical defects investigated in this study.

  • 61.
    Buvarp, Daniel
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Cost effectiveness of methods for reducing particulate matter emissions from shipping2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Marine diesel engines form particulate matter when the fuel is combusted inside the cylinders. This is due to the fuel and air not being homogenously mixed and chemical processes occurring as a result. These particles are then discarded into the atmosphere together with the exhaust gases, where they then may end up harming humans and the environment. Coal power plants, industry and diesel powered cars and trucks have regulations on them limiting the amount of particulate matter that they may emit. Ships have no such regulations on them yet, but they are expected to come.

    There are many ways that these emissions may be reduced, but the methods also need to have low costs associated with them both considering one time investments and long term maintenance and operation. Since it may soon be relevant for ships to start implementing methods for reducing their particulate matter emissions, there is a need for information regarding both effectiveness and cost for different available mitigation methods. Therefore, this study looked at available methods from this viewpoint and analysed the data. A variety of methods were found, ranging from reducing energy usage aboard, to using nuclear propulsion. Some of the methods were found to be quite effective and others not effective at all. The costs ranged from a net gain to doubling the cost of the ship.

    In the end several recommendations are made in order to provide clear information to the industry about which methods are worth looking in to, and in which circumstances these methods should be used. All ship operators are recommended to increase the fuel efficiency of their ships, reduce energy consumption, and if logistically possible reduce their cruise speed, as well as consider converting to alternative fuels. If those recommendations are not possible or not enough, the use of certain suggested exhaust gas cleaning methods is recommended.

  • 62.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Björklund, Stefan
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Johansson, Jimmy
    Volvo Aero Corporation, Trollhättan.
    Wigren, Jan
    Volvo Aero Corporation, Trollhättan.
    Clogging and lump formation during atmospheric plasma spraying with powder injection downstream the plasma gun2007In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 16, no 4, p. 512-523Article in journal (Refereed)
    Abstract [en]

    This study aimed to numerically and experimentally investigate lump formation during atmospheric plasma spraying with powder injection downstream the plasma gun exit. A first set of investigations was focused on the location and orientation of the powder port injector. It turned out impossible to keep the coating quality while avoiding lumps by simply moving the powder injector. A new geometry of the powder port ring holder was designed and optimized to prevent nozzle clogging, and lump formation using a gas screen. This solution was successfully tested for applications with Ni-5wt.%Al and ZrO2-7wt.%Y2O3 powders used in production. The possible secondary effect of plasma jet shrouding by the gas screen, and its consequence on powder particles prior to impact was also studied.

  • 63.
    Choquet, Isabelle
    et al.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    Degond, Pierre
    Universit´e Paul Sabatier, Mathématiques pour l’Industrie et la Physique.
    Lucquin-Desreux, Brigitte
    Universit´e Pierre et Marie Curie-Paris 6, Laboratoire Jacques-Louis Lions.
    A hierarchy of diffusion models for partially ionized plasmas2007In: Discrete and continuous dynamical systems. Series B, ISSN 1531-3492, E-ISSN 1553-524X, Vol. 8, no 2, p. 735-772Article in journal (Refereed)
    Abstract [en]

    Partially ionized plasmas corresponding to different ionization degrees are derived and connected one with each other by the diffusion approximation methodology. These plasmas are the following electrical discharges:a thermal arc discharge, glow discharges in local thermodynamic equilibrium -LTE- and in non-LTE, and a non-LTE glow discharge interacting with an electron beam (or flow)

  • 64.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Degond, Pierre
    Universit´e Paul Sabatier, Mathématiques pour l’Industrie et la Physique.
    Lucquin-Desreux, Brigitte
    Universit´e Pierre et Marie Curie-Paris 6, Laboratoire Jacques-Louis Lions.
    A strong ionization model in plasma physics2009In: Mathematical and Computer Modelling, Vol. 49, no 1-2, p. 88-113Article in journal (Refereed)
  • 65.
    Choquet, Isabelle
    et al.
    University West, Department of Engineering Science.
    Lucquin-Desreux, Brigitte
    University Pierre and Marie Curie, Paris, France.
    Non equilibrium ionization in magnetized two-temperature thermal plasma2011In: Kinetic and Related Models, ISSN 1937-5093, E-ISSN 1937-5077, ISSN 1, Vol. 4, no 3, p. 669-700Article in journal (Refereed)
    Abstract [en]

    A thermal plasma is studied accounting for both impact ionization, and an electromagnetic field. This plasma problem is modeled based on a system of Boltzmann type transport equations. Electron-neutral collisions are assumed to be much more frequently elastic than inelastic, to complete previous investigations of thermal plasma . A viscous hydrodynamic/diffusion limit is derived in two stagesdoing an Hilbert expansion and using the  Chapman-Enskog method. The resultant viscous fluid model is characterized by two temperatures, and non equilibrium ionization. Its diffusion coefficients depend on the magnetic field, and can be computed explicitely.

  • 66.
    Christensen, Tommy
    University West, Department of Engineering Science, Division of Production Engineering.
    Lean Automation på Saab Automobile AB: ett hållbart och flexibelt produktionskoncept2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A new concept of production – Lean Automation – is being developed and implemented at Saab Automobile AB. The aim is to develop solutions for automation that supports the Lean Production principals and way of work.

    A basic idea is that automation should be build from simple, standardized and modular equipment and that it can be reconfigured by in house personnel.

    During 2010, two pilots have been installed: Transport using a simple AGV (Lean AGV) and Lean Automation Robot Cell (LARC). Those components are parts of this study that is aiming for a production system with an unchanged high level of productivity also during periods of frequent changes in volume and product scope.

    The study underlines the importance of gathering the production personnel to enable work balancing, but also to achieve a visual process where errors urgently can be discovered and resolved. The robots work balancing requires a somewhat different approach focusing on the distribution of work elements and taking advantage of the equalizing effect in a common production flow.

    A tool for an expedient balancing of value added work is introduced. The tool is intended for the balancing of both manual and robotized work.

    Further, a method to connect the sub assembly level to the main flow is presented. Fork lift trucks and manually loaded feeders is replaced by a simple flow of AGV’s. The system is conveying information about the state of production through the presence of empty carriers. Through this visual system, plus the use of the team concept to achieve a cheap and efficient buffer, shortage of material is prevented.

    For the selection of internal material flow systems, a set of general guidelines is proposed and exemplified. Finally, the adoption of different solutions for flexibility is linked to the level of assembly and this is also linked to the aspects of parallel versus serial production flow.

  • 67.
    Cirkic, Aldin
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Qaljaee, Ali
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utveckling av motoriserad vertikal linjärenhet för kontinuerlig drift2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis work has been carried out with the purpose of developing and defining a motorized vertical linear actuator for continuous operation. In the present situation, the company does not haves a linear actuator that is capable of 1600 millimeters stroke with a load of 100 kilograms. The goal of the thesis is to present a final conceptual solution through a product development process. Software programming or electronics development is available within the company to define the function, which has been considered as a demarcation.

    The project's method is a general product development process. The first step was to establish a project plan. By identifying the client's requirements the specification could be developed which has transferred into a QFD. The next step was to develop different solutions using external and internal search methods and choose a final concept. To ensure that the final concept is safe, two different risk analyzes have been created. The concept was demonstrated in a CAD software and then different calculations and FEM analyzes were performed. The final conceptual solution turned out to be a motorized linear actuator. To make the load weightless, a pneumatic cylinder has been introduced into the system. The positioning of the weight is carried by a ball screw which is driven by a belt and a stepper motor.

    The result of calculations and analyzes of machine elements showed that the device has a theoretical service life of at least 10,000 hours. The developed conceptual solution meets the goal of establishing a final concept for a linear actuator that can handle a stroke of 1600 millimeters with a load of 100 kilograms.

  • 68.
    Clement, C.
    et al.
    National School of Engineers, University of Limoges, Limoges, 87280, France.
    Sadeghimeresht, Esmaeil
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Lyphout, Christophe
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Nylén, Per
    University West, Department of Engineering Science, Division of Production Engineering.
    Corrosion behavior of HVAF- and HVOF-sprayed high-chromium Fe-based coatings2015Conference paper (Refereed)
    Abstract [en]

    Fe-based coatings with three particular elemental compositions and two different powder particle size were prepared by high-velocity air fuel (HVAF) and high-velocity oxy fuel (HVOF) techniques. The corrosion behavior of which were comparatively studied in 3.5 wt.% NaCl solution. The results indicated that the coatings produced by HVAF process exhibited denser structure with lower porosity. Polarization and electrochemical impedance spectroscopy (EIS) tests indicated that the HVAF coatings provided better corrosion resistance than the HVOF coatings. The presence of defects was significant in HVOF coatings. The investigation illustrated that the corrosion paths initiated and grow through defects of the coating. Furthermore, adding Cr strongly improved the corrosion resistance of the coatings. The results confirmed that the cheap HVAF process could be a potential alternative to HVOF to fabricate Fe-based coatings for industrial applications.

  • 69.
    Coll Ferrari, Maria Teresa
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Forsberg, Amanda
    Uddeholms AB.
    Andersson, Jörgen
    The Swedish School of Mining and Metallurgy.
    Mikula, Pavol
    Nuclear Physics Institute ASCR.
    Beran, Premysl
    Nuclear Physics Institute ASCR.
    Effect of Austenitising Temperature and Cooling Rate on Microstructure in a Hot-Work Tool Steel2014In: Proceedings of the 6th International Swedish Production Symposium / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, p. 1-7Conference paper (Refereed)
    Abstract [en]

    The effects on microstructucture of austenitising temperature and cooling rate during hardening were studied for a hot-work tool steel. Transformation temperatures were determined by dilatometry, scanning electron microscopy was used to characterise the microstructure and both retained austenite contents and their lattice parameters were measured by neutron diffraction. For lower cooling rates, lower austenitising temperatures produce larger amounts of both retained austenite and bainite. Retained austenite in bainitic structures is higher in carbon than in martensitic structures. Consequently, lowering the austenitising temperature will affect microstructure and properties.

  • 70.
    Dahlberg, Simon
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Implementering av förebyggande underhåll som en del av ISO-certifieringar2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To become more competitive on the market Stålprofil AB has decided to obtain ISO 9001, 14001 and the upcoming 45001. As a part of this work, Stålprofil would like to implement preventive maintenance on four of the companies machines. This thesis has developed a proposal on preventive maintenance and how the company should implement it. Further an analysis of the company's current maintenance work and a study of the correlation between the three standards and preventive maintenance is carried out.

    A literature study was carried out to gathered information about maintenance. Based on this literature study and the small amount off documentation available at the company a proposal for preventive maintenance was carried out.

    In order to analyze and describe the company´s current maintenance work two observations were carried out. One observations were performed on a scheduled maintenance work and one a corrective maintenance. In addition to this reliability measurement on the four machines was carried out. The measurements should be considered whit great cautions as it only was performed during 900 minutes.

    The conclusions drawn are that the company wasting time by the staff is busy with other tasks and that the maintenance work that was observed was carried out in an unplanned way, even if they were planned.

  • 71.
    Dai, Kaixiang
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Battery cell thermal modelling and fault injection2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lithium-ion batteries are widely used in electrical vehicles due to their high energy density and high discharge current. During the charge and discharge phases, the internal resistance of batteries can generate great amounts of heat. Temperature is a very crucial factor that affects the battery life and safety. The lithiumion batteries’ heat generation and temperature distribution were studied to provide a good reference for designing cooling systems. Furthermore, extreme thermal abusive conditions such as internal short-circuit are also simulated in this project.

    This project was conducted at NEVS in collaboration with University West in Trollhättan. The heat generation of battery cells and fault injection were simulated based on experiments and CFD (computational fluid dynamic) method.

    A number of tasks had to be done in order to build the battery thermal model. The first issue that had to be resolved was being able to gain sufficient physical parameters of Lithiumion battery and this was accomplished through experiments. Once this had been achieved, the final step was to implement the constructed battery thermal model via CFD. The surface temperature of the battery cells was used to validate the simulation model. Three different discharge tests were performed in the experiment part, the discharge currents were 1C, 2C and 3C respectively. The simulated temperatures were compared with real battery temperatures and they were closely corresponding to each other in temperature. Fault injections of the battery were also simulated to have a view on the battery thermal behaviour under extreme abusive conditions. The battery internal shorting has been simulated with different internal resistance and different cross-section areas.

  • 72.
    Dalaei, K.
    et al.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Karlsson, B.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Svensson, L. E.
    University West, Department of Engineering Science, Division of Production Engineering.
    Stability of shot peening induced residual stresses and their influence on fatigue lifetime2011In: Materials Science and Engineering A, Vol. 528, no 3, p. 1008-1015Article in journal (Refereed)
    Abstract [en]

    Mechanical surface treatment methods such as shot peening may improve the fatigue strength of materials. In this study, the effect of shot peening on strain controlled constant amplitude fatigue loading of a near pearlitic microalloyed steel was investigated. The stress amplitudes throughout the whole lifetime were followed, in addition to detailed recording of stress-strain hysteresis loops, particularly at small cycle numbers. The detailed relaxation of residual stresses and the changes in full width of half maximum (FWHM) of the X-ray peak at the surface and in depth as function of the number of cycles and plastic strain were recorded. By these techniques, the onset as well as the rate of relaxation of residual stresses could be followed at different strain amplitudes. Pronounced increase in lifetime of the shot peened specimens tested at total strain amplitude smaller than 0.3% (corresponding to 0.034% plastic strain amplitude) was achieved. This coincides with reasonably stable residual stresses at the surface and in depth. © 2010 Elsevier B.V.

  • 73.
    Dalung, Emma
    et al.
    University West, Department of Engineering Science.
    Johansson, Mikael
    University West, Department of Engineering Science.
    Kvalitetssäkring av monteringsmoment vid Fasta Motorers F11-montering utifrån en process-, felläges- och effektanalys2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis an investigation has been made in order to find possibilities to assure the quality at an assembly line at Parker Hannifin Manufacturing Sweden AB:s facility in Trollhättan. The purpose with the study was to improve the quality assurance at Fixed Motors F11-assembly line, where the work was based on an already conducted process-FMEA. In order to verify and further investigate the customer perspective, an inquiry was also done to see what customers complained about, this with help of PQP, Product Quality Problems, and NCMR, Nonconformance reports.

    By analyzing the process-FMEA, PQP and NCMR reports an identification and prioritization of critical failures were made. The result from these steps was three failures, incorrect positioning of the bearing house, picking of incorrect material and incorrect gear timing. These three were considered to be the most critical failures to quality assure.

    The aim with the quality work were set to reduce the total RPN, Risk Priority Number, of the process-FMEA, which was rendered by applying a concept generation and a concept selection for the specific failures.

    In relation with the concept selection, interviews were made with staff that was considered important and vital for the project. This was made to identify specific customer needs regarding solutions to the three failures. From these needs a target specification was developed to ease the generation of concepts. After generating a number of well specified concepts, a concept selection was made using the two methods screening and scoring and an additional Parker method called 3P to further establish that the right concepts was chosen. Further it was then possible to update the process-FMEA with the chosen concept solutions and by doing that reaching the project aim. By implementing the solutions it was possible to reduce total RPN, 6415, with 47,5 percent.

  • 74.
    Danielsson, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    A flexible lean automation concept for robotized manufacturing industry2011In: Proceedings of the 4th International Swedish Production Symposium: 3 - 5, May, Lund, Lund: Swedish Production Academy , 2011, p. 361-367Conference paper (Refereed)
    Abstract [en]

    Due to constant changesin the market there is a need for low-cost and low-volume manufacturing.Usually this type of production is difficult to automate due to the time ittakes to become profitable and the inflexibility of such solutions.  Therefore, flexible automation solutions needto be addressed together with cost effective aspects. In this paper, a newconcept for the design of a flexible, robotized solution based on leanautomation is presented and simulated. The proposed lean automation concept isformed of standardized robot stations, human-robot collaboration and costeffective level of automation. The main goals are flexible automated productionsystem and reduced production cost. This paper shows that the proposed flexiblelean automation concept has some key advantages compared to the traditionalrobot cells; a longer lifetime for the robot cell as well as being easier tore-balance, introduce new parts to and expand the cell. Further, it also showsthat the proposed concept reduces the cost for automation of products with low volume.

  • 75.
    Danielsson, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Gustavsson, Steve
    University West.
    A Flexible Lean Automation Concept for Robotized Manufacturing Industry2010In: MESM 2010: 11th Middle Eastern Simulation Multiconference / [ed] Mar wan Al-Akai di, Ostend: Eurosis , 2010, p. 101-104Conference paper (Refereed)
    Abstract [en]

    This paper describes a general virtual manufacturing concept for industrial control systems. Our virtual manufacturing concept provides a distinct advantage; programming, verification and optimisation of complex real-time dependent control functions described by real control code, which can be directly transferred to the real manufacturing system. To achieve this distinct advantage, a time synchronised virtual manufacturing system is a necessity. The aim of this paper is thus to present and to describe in detail, our proposed virtual manufacturing concept. To the authors’ knowledge no such general virtual manufacturing concept, i.e. one that can correctly handle complex real-time dependent control functions, currently exists. To summarise previous work related to virtual manufacturing and industrial control systems, several critical issues have been identified. The virtual manufacturing concept proposed in this paper addresses these issues. To verify that our concept can manage these critical issues found and further is suitable in industrial applications a virtual manufacturing test case is also presented. The test case, that includes motion control (i.e. servo), complex control functions, real control systems etc., was carried out with success.

  • 76.
    Danielsson, Rebecka
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Kortläsare för återvinningscentral2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Avfallshanteringen Östra Skaraborg (Waste management Eastern Skaraborg) (AÖS) needs a new card reader for their recycling centers. This project will develop this with consideration to different forms of identification and user friendliness. The project is limited to reading the identification forms of passport, driver's license, European ID-card, national ID-card and ID-cards from banks. The information will be interpreted and translated before it is sent further to the database of AÖS, and after that ends the project's responsibility for the information. Product development methods like concept screening and concept scoring are used. Other tools include programming in C language in a programming environment, design of the box in a computer aided design program and a material selection from a material database.

    Information that steered concept generation and selection were for instance customer demands, climate data, technology in the realm of information reading and the layout of earlier mentioned identification forms.

    The chosen concept is a designed box containing a flatbed scanner (Canon CanoScan LiDE 220) that is connected to a computer (ASUS VivoPC VM42) that is powered on by the user with a start button. This computer is in turn connected to an I/O module (National Instruments USB-6002) that turns on lamps to inform the user if they need to rescan. The computer reads the characters on the ID-card and isolates the personal ID number before sending it in the form of three four digit 16 bits integers via network cable to the database that is localized in a raspberry pi server. The computer does this in its startup routine by first starting the program that scans and turns the scanned information into a pdf, then a translation program takes over that turns the information in the pdf into a string that another program processes to get the personal ID number. This program then sends a signal integer to the I/O-module, and the personal ID number (if found) via Modbus tcp to the database.

  • 77.
    Das, Kallol
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Effect of tool wear on surface integrity and burr formation in drilling of titanium alloy, Ti6Al4V2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Titanium alloys have been extensively used in aerospace industries and account for almost 30 wt% of materials used in an aerospace engine. Surface integrity of machined titanium components has a significant effect on reliability and sustainability those components in aer-ospace industry. Surface integrity could be affected by process parameters, cooling condi-tions and the wear level of the tools used in machining. An important example is the surface integrity of the holes drilled in titanium alloy Ti6Al4V. Although previous studies have shown that tool wear and cutting parameters influence surface integrity and burr formation, little work has been published about the effect of drill wear on the surface integrity and burr formation in drilling of titanium alloys in detail. In this study the influence of tool wear and use of coolant on surface integrity and burr formation in drilling of Ti6Al4V has been inves-tigated by metallographic study and micro hardness measurement of the material adjacent to holes drilled on plates of Ti6Al4V with drills of various wear levels and at three different cutting conditions. Micro structural and micro hardness alteration in drilled holes at the hole entrance, in the middle of the hole and at the hole exit as well as burr formation have been analyzed for the tool wear levels 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 mm. The tests were carried out in vertical direction without coolant and horizontal and vertical directions with coolant. The results show that limiting the wear level on the drills and use of coolant significantly lower the burr formation and microstructural alterations. Higher tool wear levels increase the depth of micro structural deformation, micro hardness and burr heights. These differences are not significant for wear levels up to 0.4 mm irrespective of cutting conditions but increase sig-nificantly when tool wear level exceeds 0.6 mm.

  • 78.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Automation Systems.
    Feedback Control of Robotic Friction Stir Welding2014Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The Friction Stir Welding (FSW) process has been under constant developmentsince its invention, more than 20 years ago. Whereas most industrial applicationsuse a gantry machine to weld linear joints, there are applications which consistof complex three-dimensional joints, requiring more degrees of freedom fromthe machines. The use of industrial robots allows FSW of materials alongcomplex joint lines. There is however one major drawback when using robotsfor FSW: the robot compliance. This results in vibrations and insufficient pathaccuracy. For FSW, path accuracy is important as it can cause the welding toolto miss the joint line and thereby cause welding defects.The first part of this research is focused on understanding how welding forcesaffect the FSW robot accuracy. This was first studied by measuring pathdeviation post-welded and later by using a computer vision system and laserdistance sensor to measure deviations online. Based on that knowledge, a robotdeflection model has been developed. The model is able to estimate thedeviation of the tool from the programmed path during welding, based on thelocation and measured tool forces. This model can be used for online pathcompensation, improving path accuracy and reducing welding defects.A second challenge related to robotic FSW on complex geometries is thevariable heat dissipation in the workpiece, causing great variations in the weldingtemperature. Especially for force-controlled robots, this can lead to severewelding defects, fixture- and machine damage when the material overheats.First, a new temperature method was developed which measures thetemperature at the interface of the tool and the workpiece, based on the thermoelectriceffect. The temperature information is used as input to a closed-looptemperature controller. This modifies primarily the rotational speed of the tooland secondarily the axial force. The controller is able to maintain a stablewelding temperature and thereby improve the weld quality and allow joining ofgeometries which were impossible to weld without temperature control.Implementation of the deflection model and temperature controller are twoimportant additions to a FSW system, improving the process robustness,reducing the risk of welding defects and allowing FSW of parts with highlyvarying heat dissipation.

  • 79.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Robotic Friction Stir Welding for Flexible Production2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Friction Stir Welding (FSW) is a modern welding process that joins materials by frictional heat, generated by a rotating tool. Unlike other welding processes, the material never melts, which is beneficial for the weld properties. FSW is already widely adopted in several industries but the applications are limited to simple geometries like straight lines or circular welds, mostly in aluminium. The welding operation is performed by rigid FSW machines, which deliver excellent welds but puts limitations on the system in terms of flexibility and joint geometries. Therefore, several research groups are working on the implementation of the FSW process on industrial robots. A robot allows welding of three-dimensional geometries and increases the flexibility of the whole system. The high process forces required for FSW, in combination with the limited stiffness of the robot brings some extra complexity to the system.  The limitations of the robot system are addressed in this licentiate thesis.

    One part of the thesis studies the effect of robot deflections on the weld quality. A sensor-based solution is presented that measures the path deviation and compensates this deviation by modifying the robot trajectory. The tool deviation is reduced to an acceptable tolerance and root defects in the weld are hereby eliminated. The sensor-based method provided better process understanding, leading to a new strategy that uses existing force-feedback for path compensations of the tool. This method avoids extra sensors and makes the system less complex. Another part of this work focuses on the extra complexity to maintain a stable welding process on more advanced geometries. A model is presented that allows control of the heat input in the process by control of the downforce. Finally, the robot’s limitations in terms of maximal hardness of the materials to be welded are investigated. Parameter tuning and implementation of preheating are proposed to allow robotic FSW of superalloys.

  • 80.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Deflection model for robotic friction stir welding2014In: Industrial robot, ISSN 0143-991X, E-ISSN 1758-5791, Vol. 41, no 4, p. 365-372Article in journal (Refereed)
    Abstract [en]

    Purpose - This paper aims to present a deflection model to improve positional accuracy of industrial robots. Earlier studies have demonstrated the lack of accuracy of heavy-duty robots when exposed to high external forces. One application where the robot is pushed to its limits in terms of forces is friction stir welding (FSW). This process requires the robot to deliver forces of several kilonewtons causing deflections in the robot joints. Especially for robots with serial kinematics, these deflections will result in significant tool deviations, leading to inferior weld quality. Design/methodology/approach - This paper presents a kinematic deflection model, assuming a rigid link and flexible joint serial kinematics robot. As robotic FSW is a process which involves high external loads and a constant welding speed of usually below 50 mm/s, many of the dynamic effects are negligible. The model uses force feedback from a force sensor, embedded on the robot, and predicts the tool deviation, based on the measured external forces. The deviation is fed back to the robot controller and used for online path compensation. Findings - The model is verified by subjecting an FSW tool to an external load and moving it along a path, with and without deviation compensation. The measured tool deviation with compensation was within the allowable tolerance for FSW. Practical implications - The model can be applied to other robots with a force sensor. Originality/value - The presented deflection model is based on force feedback and can predict and compensate tool deviations online.

  • 81.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Soron, Mikael
    ESAB Welding AB .
    Ilar, Torbjörn
    University West, Department of Engineering Science, Division of Production Engineering.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Process and Product Development.
    Friction stir welding with robot for light vehicle design2010In: Proceedings from the 8th International Friction Stir Welding Symposium: Timmendorfer Strand, Germany 18-20 May 2010, The Welding Institute , 2010Conference paper (Other academic)
    Abstract [en]

    Reducing weight is one of the enablers to design more environmentally friendly vehicles. Friction Stir Welding (FSW) supports low weight design through its capability to join different combinations of light weight materials, e.g. different aluminium alloys, but also through its possibilities in producing continuous joints. StiRoLight is a recently started project for robotised FSW for joining of light weight materials emphasising on the vehicle industry, an industry with a long-time experience of robotic welding. The first task involves investigation of force feedback for maintaining the desired contact force. Another important aspect in robotised FSW is the compliance of the robot, which may result in deviations from the pre-programmed path as a result of the high process forces experienced during the welding operation. The further exploration of three-dimensional FSW seams and definition of the process windows will be part of further research within this project.

  • 82.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Production Engineering.
    Verheyden, Bert
    University West, Department of Engineering Science, Division of Production Engineering.
    Robotic Friction Stir Welding for Automotive and Aviation Applications2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Friction Stir Welding (FSW) is a new technology which joins materials by using frictional heat. Inthe first part of this thesis, a profound literature study is performed. The basic principles, therobotic implementation and possibilities to use FSW for high strength titanium alloys areexamined. In the next phase, a FSW-tool is modelled and implemented on an industrial robot in arobot simulation program. Reachability tests are carried out on car body parts and jet engineparts. By using a simulation program with embedded collision detection, all possible weldinglocations are determined on the provided parts. Adaptations like a longer FSW-tool and amodified design are suggested in order to get a better reachability. In different case studies, thenumber of required robots and the reduction of weight and time are investigated and comparedto the current spot welding process.

  • 83.
    Edstorp, Marcus
    University West, Department of Engineering Science, Division of Production Engineering.
    Weld Pool Simulations2008Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This investigation is devoted to the study of welding and its effect on the workpiece, focusing on the thermo and fluid dynamical phenomena occuring during a autogenous or nonautogenous arc fusion welding process. Its aim is to simulate the behaviour of the weld pool and analyze the consequence of the solid-liquid phase change, thus obtaining a methodology for predicting the appearance of weld defects related to solidification and cooling. In order to accomplish this, we solve equations governing a number of continuum mechanical and electromagnetical quantities, as well as consider the motion of the freely moving boundary of the weld pool. Since the state of these quantities is strongly influenced by phenomena such as arc and droplet impingement, non-isothermal phase change, surface tension, Marangoni forces and Lorentz forces, much effort is necessarily devoted to the modelling of the corresponding fluxes and sources, as well as to the implementation of computationally efficient techniques for simulating the geometrical deformation of the workpiece, which in our setting is entirely determined by the motion of the weld pool surface.

    Common to all arc fusion welding processes is the employment of a welding arc. Many techniques rely on the arc to clean and shield the workpiece during the process, however in this study we consider it to be its main purpose to cause the local increase of thermal energy that is required for the establishment of the weld pool, and also to exert the mechanical forces that provoke the subsequent fluid flow which enhances heat transfer and facilitates weld penetration. The physics of the welding arc itself is quite intricate, and although the modelling of the arc is not the prime objective of this research project, we conclude that arc forces act on the pool surface, and that the investigation of the arc behaviour is important insofar that it provides input to the pool model and thus enables a more accurate prediction of the quality of the weldment that is created once the pool has solidified

  • 84.
    Edström, Johan
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Hammar, Samuel
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Framtagning av beräkningsmodell för uppvärmningssystem: med fokus på kombinationen fjärrvärme och frånluftsvärmepumpar2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As a result of the EU's environmental 2020 goal, the Swedish government and municipal boards has put up internal goals to reduce energy consumption. EU 2020 goal aims to reduce energy consumption in Europe by 20 percent by the year 2020 from that the target was set in 2010.

    At the municipal level, this has meant that private but mainly public housing properties have been required to review their energy use. The work in this report is based on one of the savings measures that have been taken, which is to supplement existing district heating systems with exhaust air heat pumps. The project aims to develop a calculation model for evaluation and computation for this type of system.

    To create a reliable basis for decisions, efforts were made to produce just calculations. Existing computational models are focused on economic factors and thus takes little consideration of technological aspects and environmental factors. The aim of the work has been to create a computational model which more closely reflects the real situation and demonstrates a more informative decision basis.

    The work began with a literature review which included relevant research and basic facts about exhaust air heat pumps and district heating systems. The calculation model has been developed continuously during the project in which new functions and new information constantly has been added.

    The project has resulted in a working computational model which includes many more parameters than previous reviewed models. Together with the client three sub goals were set up for the model, these were:

    •  To intuitively present information and data.
    •  To create a transparent structure which is simple to follow.
    •  To create a flow through the model, which follows a desired work process.

    These goals are considered to have been fulfilled in the developed calculation model, however, it's possible to further develop this model. The model could, for example, be supplemented with more automated optimization calculations and be adjusted to handle other kinds of heating systems.

  • 85.
    Edvinsson, Åke
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Förbättringsförslag för kyl och värmesystemet i en GasHub-anläggning för Stirlingmotorer2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 1816 the Stirling engine was invented and has since been tested in a variety of applications. Cleanergy using Stirling technology in its solar and gas plants to produce electricity and heat. The goal of this work is to develop proposals for an energy-efficient way to control the cooling of a GasHub plant to the desired temperatures and draft proposals on combined heat and power solutions known as CHP (Combined Heat and Power). The method of work was to identify how the system looks like, customer visits and the development of proposals for improvement. A GasHub is a facility built out of a container in which this has been designed to connect and place GasBox units. A GasBox is a unit of the Stirling engine, generator and gas burners. A necessary feature of a Stirling engine is its cooling, partly to engine components is not too hot and partly to cool the heated gas. This is because the pressure and volume of gas to be reduced in the cooling phase of the motor to rotate. Cooling and heating system in GasHub linking together all GasBox where glycol mixed cooling water rotates around in a loop. The heat from the Stirling engines is transmitted in the heat exchanger to the cooled coolant from GasHub and in this way is reduced when the heat in the cooling system to Stirling engines. A GasBox produces about 7,2kW electricity when it runs on biogas and 20kW heat energy. The customers who have chosen to install the heating system uses this mainly to heat buildings and land heat outdoors to keep this clean of snow and ice. A GasHub 5 plant produces about 36 kW of electricity. According to the data Cleanergy has estimated the average parasitic loads to about 1.5kW or about 4% of the total energy production. A study was conducted on a GasHub facility in Ulricehamn to, among other things to find out how the customer experienced how large parasite loads were and what could be the reason for this. The calculations are carried out shows that the circulation pump is correctly sized. The pump needs to cope with a delivery height of 9 meters and need a flow of 8.6 m3 / hour. The result has three suggestions for improvement of control system for the cooling presented. The first proposal is control by the temperature, then the circulation pump speed is controlled so that a temperature difference of 12 degrees from the input heat to GasBox and out of this. The second proposal involves driving at various differential pressures for various operating conditions. The third proposal involves installing a thermostat on GasBox to regulate the heat out of it. The improvement proposal is about reducing waste heat and energy are proposed to isolate pipes in GasHub. Calculations show that it is possible to save 35kWh heat-energy per day. The proposals of the CHP solutions suggested that the heat can be used for air conditioning if an adsorptions-chiller is used. It is further proposed that the heat stored in the bedrock and cooling taken from there to cool GasHub. The discussion and analysis section of the report assesses improvement proposals and temperature differential regulation proposal is considered that it is relatively easy to implement and is the most optimal for the circulation flow and lower energy consumption. Among CHP proposals considered to be relatively easy to install an adsorptions-chiller to use the heat to the air. Furthermore, the chapter raises the question whether it would be possible to cool using a lower flow in the system because this could save more energy. The question of whether it would be possible to raise the temperature in the engine of a major gas coolers are used are highlighted. The conclusion of the report states that GasHub is today a fully functional facility for the production of electricity and heat, however, that there is much potential for improvement in the plant. It is found that rules the proposals is estimated to halve the energy consumption of the circulation pump.

  • 86.
    Eggertsen, P. -A
    et al.
    University of Technology, Div. of Material and Computational Mechanics, Dept. of Applied Mechanics Chalmers.
    Mattiasson, Kjell
    University of Technology, Div. of Material and Computational Mechanics, Dept. of Applied Mechanics Chalmers.
    Larsson, Mats
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    A comprehenisve analysis of benchmark 4: Pre-strain effect on springback of 2D draw bending2011In: AIP Conference Proceedings, Seoul, 2011, Vol. 1383, p. 1064-1071Conference paper (Refereed)
    Abstract [en]

    In order to be able to form high strength steels with low ductility, multi-step forming processes are becoming more common. Benchmark 4 of the NUMISHEET 2011 conference is an attempt to imitate such a process. A DP780 steel sheet with 1.4 mm thickness is considered. In order to understand the pre-strain effect on subsequent forming and springback, a 2D draw-bending is considered. Two cases are studied: one without prestrain and one with 8% pre-stretching. The draw-bending model is identical to the "U-bend" problem of the NUMISHEET'93 conference. The purpose of the benchmark problem is to evaluate the capability of modern FE-methods to simulate the forming and springback of these kinds of problems. The authors of this article have previously made exhaustive studies on material modeling in applications to sheet metal forming and springback problems, [1],[2],[3]. Models for kinematic hardening, anisotropic yield conditions, and elastic stiffness reduction have been investigated. Also procedures for material characterization have been studied. The material model that mainly has been used in the current study is based on the Banabic BBC2005 yield criterion, and a modified version of the Yoshida-Uemori model for cyclic hardening. This model, like a number of other models, has been implemented as User Subroutines in LS-DYNA. The effects of various aspects of material modeling will be demonstrated in connection to the current benchmark problems. The provided material data for the current benchmark problem are not complete in all respects. In order to be able to perform the current simulations, the authors have been forced to introduce a few additional assumptions. The effects of these assumptions will also be discussed. © 2011 American Institute of Physics.

  • 87.
    Ehnberg, Jimmy S. G.
    et al.
    Chalmers University of Technology, Department of Electric Power Engineering.
    Bollen, Math H.J
    Chalmers University of Technology, Department of Electric Power Engineering.
    Simulation of global solar radiation based on cloud observations2005In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 78, no 2, p. 157-162Article in journal (Refereed)
  • 88.
    Ehnberg, Jimmy S.G.
    et al.
    Chalmers University of Technology,Department of Electric Power Engineering.
    Agneholm, Evert
    Gothia Power Ab, Göteborg.
    Reverse Motor Control for CCLs in AC Hybrid Minigrids2006In: 3rd European conference on PV-hybrid and Mini-grid, 2006, p. 138-143Conference paper (Refereed)
  • 89.
    Ehnberg, Jimmy S.G.
    et al.
    Chalmers University of Technology,Department of Electric Power Engineering.
    Bollen, Math H.J.
    STRI Ab,Ludvika.
    Generation Reliability for Small Isolated Power Systems entirely based on Renewable Sources2004In: Power Engineering Society General Meeting, 2004. IEEE, 2004, p. 2322-2327 Vol 2Conference paper (Refereed)
  • 90.
    Ehnberg, Jimmy S.G
    et al.
    Chalmers University of Technology, Department of Electric Power Engineering.
    Bollen, Math H.J
    STRI AB, Ludvika, Sweden.
    Reliability of a small power system using solar power and hydro2005In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 74, no 1, p. 119-127Article in journal (Refereed)
  • 91.
    Ekström, Johanna
    et al.
    University West, Department of Engineering Science.
    Emanuelsson, Stefan
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Förstudie till implementering av papperslös verkstad2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Under sommaren 2012 genomfördes ett examensarbete på Siemens Industrial Turbo­mach­inery AB i Trollhättan gällande möjligheterna att införa pappers­lös verkstad. Syftet med examensarbetet var att kartlägga möjligheterna att minska administrativ hant­ering av produktions­orderkort och öka realtidsuppdatering. För att av­gränsa studien avsåg examens­arbetet endast flödet av produk­tions­­­order­kort ifrån plan­er­ings­avdelningen genom två pro­duk­tions­grupper och vidare in på gods­­­­avdel­ningen.

    För att kartlägga flödet för den manuella hanteringen av produktionsorderkort upprättades värdeflödesanalyser. Dessutom genomfördes ett studiebesök på Volvo Aero Corporation för att se hur ett annat företag har gjort för att eliminera elektronisk produk­tionsorder. Utifrån värdeflödesanalyserna och studiebesöket identifierades tre frågeställ­ningar vilka an­sågs vara betydelsefulla för att kunna införa elektronisk produk­tions­order. Dessa var huru­vida affärssystemet klarar av att hantera införande av elektronisk produk­tions­order, hur spårbarheten av material skall bibehållas samt hur godsavdelningen skall få information om var detaljer skall förflyttas. För att besvara dessa frågor genomfördes 15 inter­vjuer med per­sonal från Siemens Industrial Turbo­machinery i Trollhättan, med per­sonal från huvud­kontoret i Finspång samt med personal från systemutvecklingsföretaget Else AB.

    Informationen från alla intervjuer samt studiebesöket på Volvo Aero Corporation belyser möjligheterna och problemen med att eliminera produktionsorderkorten och samman­ställ­des i en utvärdering. Denna utvärdering ligger till grund för kartläggningen av det fram­tida tillståndet, vilken visar ett tänkbart arbetssätt när produktions­order­korten tagits bort och ersatts med elek­tronisk produktions­order. Det som huvud­sakligen belyses i det framtida tillståndet är att affärssystemet är förberett för elek­tronisk produk­tions­order, dock rekom­men­deras införande av Warehouse Management System samt ett transportssystem. För att under­­lätta implementering av elektronisk produktionsorder skulle införande av ett web­baserat användargränssnitt vara lämpligt.

  • 92.
    Elbing, Tommy
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Parametriserad stötfångarmodell av öppen profiltyp2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis has been performed at Benteler Aluminium System Norway in Raufoss in co-operation with Benteler Engineering Service. Since the automotive industry require lighter and safer vehicles, more and more car manufactures change to a bumper beam in alumi-num instead of the traditional one in steel. A lighter vehicle can directly be linked to lower fuel consumption and therefore also a reduced environmental impact.

    The bumper beam that BASN manufactures today is based on extruded aluminum profiles which are bend and formed into desired geometry. The uniqueness of BASN is that the whole value chain is available within the same area, from casting of aluminum alloys to extrusion, forming and finishing.

    To make changes in CAD models is time consuming and costly. To achieve a more time efficient process was the goal to create a simple and accurate parametric CAD model of a bumper. Changes can then be performed in a fast and simple way and lead times of devel-opment can be reduced.

    A CAD-model has been developed that uses parameters to control the geometry of the bumper. The bumper is of open profile type. The CAD-program calculates simple collision parameters such as the maximum bending moment in pure bending and maximum force. Further has a tool been implemented that characterizes the bumpers middle section to in-crease rigidity.

    The goal of creating a parameterized CAD model is satisfied. It is also possible to create parameterized models for other types of profile like closed profiles or multi-chamber pro-files.

  • 93.
    Elfwing, Jonny
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Thersthol, Alexander
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Konceptutveckling av provriggsutrustning för framdrivningssystem2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To carry out different tests on an electric car’s driveline, it often necessary to produce different unique test rigs, which may become costly in terms of both time and money. Thus, in the development of vehicle propulsion systems, there is a need for new modular rigging equipment that can allow shorter set times for switching between different test missions and more tests could be performed at the same time. The purpose of the thesis work is to produce one or more theoretical concepts of a test rig module. In the method section, a theoretical frame of reference is presented, describing the theories and assumptions that were considered relevant for solving the task. The approach to achieving the results includes, among other things, the tools TRIZ, idea generation, literature study and concept screening and weighting matrices. The result includes a proposal for a module-based concept and its characteristics and possibilities are described. The concept consists of three different types of functional elements which are objects that are used to hold and linearize the different components of an electric cars driveline, a module used to position and stabilize the objects and fasteners to attach components to each other and to the T-slots. The final part discusses the implementation and outcome of the thesis work, but there are also suggestions for further studies. The conclusion is that it seems possible to carry out tests with different drivelines using the module-based concept.

  • 94.
    Eliasson, Richard
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Development of new concepts for a blow moulded gymshaker2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project report covers how to perform a structured product development process. The process involves several steps in which different methods and tools are used.

    The purpose of the project is to develop a gymshaker in order to make the company, Emballator Mellerud Plast AB, competitive on the gymshaker market. The main goal of this project has been to present a viable proposal for a physical prototype of the product.

    The product development process starts, in this report, with opportunity identification and ends with a prototype of the product. Methods that are used throughout the process are for example; structured requirement lists with metrics and values, concept generation by exploring different sources, concept selection through different selection tools and computer-aided design modelling.

    A final model of the gymshaker was not officially made, but a preliminary model and drawing were made.

    In conclusion, structured documentation was important throughout the whole process to ensure that every solution was preserved and to be able to reflect thoroughly. The product development process resulted in a prototype of a gymshaker with only three components, the cap (two-parted) and the body. The shaker will be a low cost product considering the few components and the material cost

  • 95.
    Ellers, Fredrik
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Knutsson, Stefan
    University West, Department of Engineering Science, Division of Automation Systems.
    Utveckling, konstruktion och CE-märkning av robotcell för utbildningssyfte2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis work has focused on the efforts to CE-mark a robot cell that has been developed by us to be used for educational purposes. A significant part of the thesis work was to gather the necessary information regarding the CE-marking, robot safety and risk assessments. Security measures have been taken to achieve the requirements concerning the standards, and the conditions concerning both the limited surface and the environment the robot cell is to be used in. This thesis work has developed a large amount of technical documentation. This will be the basis for the final CE-marking of the robot cell. The CE-marking is not completed because the robot cell is not fully developed yet. This leads to that the CE marking cannot be completed until the final tests have been performed on the completed cell, regarding the construction and safety integrity of the structure

  • 96.
    Emanuelsson, Viktor
    et al.
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Wahlberg, Christoffer
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Omkonstruktion av fixtur avsedd för manuell svetskontroll av turbinmotorstativ2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor's thesis treats the production of a fixture for manual physical and visual weld inspection of an aircraft engine stand, 30k TEC (Turbine Exhaust Case), for GKN Aerospace in Trollhättan. The main problem is that the inspection of 30k TEC had not previously occurred to the extent that is current today. The purpose was to facilitate the inspection staff's work situation and to determine whether it is possible to use parts of a fixture adapted to a different aircraft engine stand.The work is based, for the project, on relevant methods that includes data collection, inter¬pretation of collected data, concept generation and concept selection. Interested parties were identified with their respective demands on the fixture and the environment. Concept proposals were generated along with interviews and observations of similar fixtures. The concept proposals went through a concept selection process, which resulted in a final concept.The final concept allows motorized rotation of the aircraft engine stand and it is equipped with supports which prevents the aircraft engine stand to fall off the fixture. The support prevents the turbine exhaust case from falling off during the inspection, which could result in both material damage to the aircraft engine stand and equipment as well as physical damage to the inspection staff. Due to the possibility to rotate the aircraft engine stand with a motor the fixture is classified as a machine and must therefore be CE marked by the manufacturer. The work therefore includes in-depth knowledge in the Machinery Directive and the requirements for CE marking of machines. To meet the ergonomic aspects for the inspection staff, guidelines for ergonomic work.The report presents the final concept and its included components. The employer's work deliverables consists of order documents ready to be sent to the manufacturer of the fix-ture containing drawings and parts lists. Both manufacturers and inspection staff have shown a positive attitude towards the outcome.

  • 97.
    Engman, Linus
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Stanisic, Oliver
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Kravspecifikation som förbättrar förpackningslogistik och arbetsmiljö: En problemlösande studie hos smaksättningsföretaget Santa Maria2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The study presented in the report is a qualitative study conducted by two students at Högskolan Väst. It includes a logistics and a working environment problem at the spice company Santa Maria. The report writers have been told by Santa Maria to review a certain number of articles/commodities that are delivered from different suppliers in a way that makes it unfavorable for employees when they handle the raw materials. The problem can be anything from high pallets, to pallets packed in a way that makes it difficult for employees to handle in certain parts of Santa Maria's production process. To try to fix this, a requirement specification must be prepared which is also the goal of the study. The idea is that Santa Maria will have the opportunity to demonstrate to its suppliers how the raw materials should be packaged and dispatched, and using a requirement specification as a source for decision making. The procedure in the study is based on the steps that follows in a product development process, which means that several different methods have been used to obtain useful information. Such as a current situation analysis, stakeholder analysis, benchmarking and SWOT analysis. Using these methods, we received the necessary information about Santa Maria, such as the current situation, the stakeholders included in the study, and the strengths and threats that the study and requirement specification causes. By carrying out a variety of interviews with Santa Maria, the report writers have gained a good picture and understanding of the problem that the employees experienced.

    The preparation of the requirement specification was based primarily on two aspects, such as economic and work environment aspects. This resulted in a requirement specification that covered both the working environment of Santa Maria employees and the economic aspects, such as how the raw materials should be loaded to optimize loading in a container. With the recommendations made by the report writers, Santa Maria should now have a good awareness of what things that should be improved and how to proceed to get a successful modification.

    The result in the form of the specification was analyzed in the discussion to determine its relevance. This led to the theory and previous research being rooted in the requirements specification. Both theory and previous research were in line with the requirements of stakeholders for the design of pallet goods. The conclusion drawn is that the study is relevant and the problem is appropriate for Santa Maria to consider. By demonstrating that employees' needs are considered, it can gain commitment and motivation can be generated by employees.

  • 98.
    Ericson Öberg, Anna
    et al.
    Chalmers Tekniska Högskola.
    Hammersberg, Peter
    Chalmers Tekniska Högskola.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    The right evaluation method - an enabler for process improvement2013Conference paper (Other academic)
    Abstract [en]

    This paper aims at describing the procedure where an alternative evaluation process was developed to support the improvement of both welding and weld quality evaluation. Welded structures are important when striving for reduced fuel consumption due to vehicle weight. Hence good control of the fabrication process is critical to keep welding performance on target, avoiding waste in terms of added weight and overproduction. The resulting distribution of weld weight has shown to be an important control parameter in the sense of keeping cost down.

    To identify the causes for deviations between actual and theoretical weld weight, information about the weld was needed. The currently used evaluation method showed not to be capable of giving the information needed. It was necessary to know the throat size as well as weld geometry. The current evaluation method introduced more variation due to the measurement than the actual fabrication process itself, leading to drift of process target and overproduction.

    To fulfil the need of information, that different functions within the company had, a PULL-approach was used. The information need, information presentation and sequence were outlined for each information receiver individually. An alternative measurement method was developed and named WIA – Weld Impression Analysis. The method consists of two parts; creating the replica and analysing the shape in an image analysis program.

    The method was tested to see if it was capable of delivering accurate and precise measurements, satisfying repeatability and reproducibility requirements for this particular situation. A thorough measurement system analysis was carried out. The measurement system assigned 98.98% of the total variation to part-to-part variation corresponding to long-term process variation. The variation that stems from taking the impressions and preparing them was as well investigated, also showing satisfying results. Finally it was investigated if the impressions reflect the true shape of the welds accurately. The results showed a tendency of slightly higher cross sectional areas in the range of 0-3 %. This however indicated that the accuracy of the measurement system was sufficient for its purpose.

    The PULL-approach generated a sufficient method which enabled the possibility to perform process improvement and gain large production cost savings.

  • 99.
    Eriksson, Amanda
    et al.
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Westman, Anna
    University West, Department of Engineering Science, Division of Mechanical Engineering and Natural Sciences.
    Uppgiftsväxling: identifikation av motstånd och förslag tillförbättringar vid NU-sjukvården2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The lack of nurses is becoming a national problem in Sweden as well in NU-Hospital Group, region Trollhättan and Uddevalla. In 2016 NU-Hospital Group area I of III started a program for switching duties performed by nurses with focus on optimizing the resources. During the winter of the same year as the project started the leaders of the clinics began to resist the change. This year in autumn of 2017, NU-Hospital Group will launch a new program to switch nurses’ duties throughout the organization. This report addresses why the project “task switching” stagnated and what could be done differently in the upcoming program. The purpose of this report is to help NU-Hospital Group to achieve an improvement, avoid resistance from the co-workers and thereby implement a successful program. The authors have completed their work through performing an organizational charting, studying status reports, and applying the methods of literature reviews, interviews, surveys and a compilation of other hospitals achievements and what they have accomplished. These selected methods are chosen to ensure the result is valid and reliable. The healthcare needs to constantly improve their organization. The program “task switching” stagnated because the management perceived the resistance, which was of importance. The change made the leaders of the clinics feel lack of treatment, participation and trust. The purpose and goal of the project was unclear and changed during time. NU-Hospital Group still understand that this change is necessary for the healthcare and therefore they are planning to start the new program of switching duties, which concerns the entire organization. Ahead of the upcoming program the authors have identified a number of suggestions to improve the program. The suggestions are: focus on the project management, focus on the existing processes before switching duties, involvement from the employees and apply a Lean-philosophy. The result of this thesis is considered reliable because several methods have been used and the result have been analyzed from different perspectives. Therefore, we assert the validity and reliability of the study.   

  • 100.
    Eriksson, Kristina. M.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    A comparison of changeover time reduction through design changes and changeover sensitive heuristics2007In: PLANs forsknings- och tillämpningskonferens 2007: kundfokuserade varor och tjänster : artiklar från konferensen på Tekniska högskolan i Jönköping 5-6 september 2007, PLAN - Logistikföreningen , 2007, p. 51-66Conference paper (Refereed)
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