his.sePublications
Change search
Refine search result
78910 451 - 482 of 482
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.
  • 451.
    Treijner, Christofer
    et al.
    University of Skövde, School of Technology and Society.
    Svensson, Mattias
    University of Skövde, School of Technology and Society.
    Experimentell studie av reversibel axialfläkt: Med avseende på utformning av nav/skovelbas samt minsta/största skovelvinkel2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In this thesis a new construction of a reversible axial flow fan is being studied. By performing experiments on different variants of a fan wheel an evaluation is done. Factors to be varied are the design of the hub and the blade base as well as blade angle. All tests is performed in a test rig established by AB Akron-maskiner. The test rig is constructed according to ISO 5801.

    Experiments show that the hub design itself does not have a significant impact on the performance. Changes in performance are detected when various combinations of hubs and blade base are tested. The greatest difference in efficiency between the best and worst hub/blade base combination is about 20%. It is of great interest to have access to this information because a simpler design of the hub allows greater flexibility in the manufacturing. An upper limit for the maximum blade angle is partly due to the appearance of stall but mainly the limitations of the fan motor. The minimum blade angle has also the result founding in engine size. The performance is improved if the radial airflow through the blades cavity is blocked. A blockage causes an increase in efficiency by 5-12% and a reduction in sound power level of 2-3 dB. For optimal performance, the design of the hub should be spherical and the blade base curved and shaped to the hub. This is the same type of hub that is produced today. Maximum and minimum useful blade angle is 50° and 25° to the rotation direction.

  • 452.
    Tressing, Erik
    et al.
    University of Skövde, School of Engineering Science.
    Banck, Gustav
    University of Skövde, School of Engineering Science.
    Utveckling av laddstolpe med befintlig elektronik2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During this project you will see the process behind the development of a charging station for electric vehicles with electronics developed by Sea Ice AB. Sea Ice AB wanted two concepts, one accessory that would allow installations of a charging box without access to a wall. Also a concept of a charging pole. These concepts had to be discreet, and blend in with the surrounding environment, which will be the niche for the produkt. The needs and desires from the user became a central topic for the project. In the prestudy these were found using forms, observations and other methods. The ideageneration were performed on the problems “form, cablemanagement, and function” which later will be welded together and solve the problem as a whole. Mockups, user tests and creative thinking were heavily used during the ideation phase. The project is summarized, evaluated, and communicated with CAD-models and an appearance prototype. All parties are satisfied with the result but its still uncertain if it's going to produktion.

  • 453.
    Udén, Emelie
    et al.
    University of Skövde, School of Engineering Science.
    Westerberg, Sara
    University of Skövde, School of Engineering Science.
    Utveckling av hygienisk golvränna2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    AB Furhoffs Rostfria was founded in Skövde in 1899 to produce pots and cauldrons in copper. Today´s production is focused on products for HVAC (heating, ventilation and air conditioning) as well as for restaurant kitchens and customized products. The production is located in Skövde with machines suited for processing stainless steel.

    Demands from the market as well as Furhoff´s competitors are focusing on hygienic floor drain gutters. Because of this, Furhoffs wants to be the leading company of this kind of development. This project aims to develop a floor drain gutter that is suitable for environments with high requirements of hygiene to prevent spreading of diseases. These environments can be food factories, laboratories, hospitals and restaurant kitchens. The product needs to be safe to use in industries where traffic from heavy vehicles occur. This means that the product must withstand a load of 12 500 kg.

    To adjust the product to fit the user, interviews were performed in a large dairy, a food factory and in a restaurant. An observation was also performed in the restaurant to observe the cleaning process of a floor drain gutter. The information from the user study resulted in a list of needs. These, combined with demands from the company, formed the product specification. This specification was the basis for how the product later was developed. The components of the floor drain gutter, gully with a stench trap, gutter, cover and strainer basket, was developed separately and adapted to each other. Tests and cost analysis were performed to make well-founded concept choices. Water flow and removal of waste was tested to choose the most optimal gutter profile. To make sure the floor drain gutter is safe to use in the intended environment, load tests, slip tests and tests of flow rates were made.   

    The final product is adjusted for Furhoff´s production methods. The floor drain gutter fulfils the requirements and is suitable for environments with high hygiene demands. The result from this thesis will be used for further development of Furhoff´s future floor drain gutter. 

  • 454.
    Vahlgren, Simon
    University of Skövde, School of Engineering Science.
    Stopptidsanalys och standardiseringsförslag: Examensarbete på Semper AB2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The food processing company Semper AB in Götene has, after implementing software for monitoring production down time,identified a need for improvements considering time consumption in the cleaning process of Torn 4.After conducting studies, evaluations and analyses within the production, a need for standardization and time determination for the process has been identified. The project has resulted in propositions for new work standards considering time consumption for the included operations within the cleaning process, as well as definitions regarding the steps conducted parallel to one another to reduce the required time and streamline the process.The problem which was initially identified, as visualized through Semper’s down time tracking soft-ware Axxos, has through the course of the project been clarified as a symptom of a neglected work around standardization on the studied object. The need for increased standardization, control and planning is called for from both production management and operators alike, hence the competence involving the process exists within the organization, but need to emphasize and make use of it is nec-essary in a more efficient way.

  • 455.
    Vandi, Poujan
    et al.
    University of Skövde, School of Engineering Science.
    Salomé, Joel
    University of Skövde, School of Engineering Science.
    Arbetssätt för att automatisera inhämtning av data till simuleringsmjukvaran FACTS2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
  • 456.
    Vennapusa, Siva Koti Reddy
    University of Skövde, School of Engineering Science.
    Design of bi-adhesive joint for optimal strength2019Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    To support the trust in the design development of adhesively bonded joints, it is important to precisely predict their mechanical failure load. A numerical simulation model with a two-dimensional linear elastic cohesive zone model using a combination of a soft and a stiff adhesive is developed to optimize the strength of a lap-joint. Separation under mixed-mode conditions (normal and shear direction) is considered. By varying the length of the adhesives, the fracture load is optimized. The results obtained from the numerical experiments show an improvement in strength.

  • 457.
    Vilaplana Alamilla, Maria
    et al.
    University of Skövde, School of Engineering Science.
    Hylander Ruiz, Gustavo
    University of Skövde, School of Engineering Science.
    Design of a modular delivery vehicle for cities2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report describes the conceptual design and development of a virtual prototype of a sustainable delivery vehicle for cities in the European Union. The project was carried out as a multidisciplinary project where one product design engineering student and one mechanical engineering student participated. The project’s design process was based on “The Mechanical Design Process” methodology by Ullman and secondary it was influenced by the product process of Ulrich & Eppinger.

    The initial phase of the project aimed to define the problem area and to set the requirements for the vehicle. This phase included: study of the problem, study of stakeholders, market research and an ergonomics study. When the requirements were set and clarified, the concept generation phase followed. The generated design concepts were then assessed according to the fulfilment of set requirements. One final concept was chosen for further development in the following product generation phase. In this phase, the vehicle was designed using virtual tools, and the design was developed and evaluated in further detail. The final concept is considered to fulfil most requirements, although there are some requirements that require further investigation and development.

  • 458.
    von Dewall, Johannes
    et al.
    University of Skövde, School of Engineering Science.
    Johansson-Näslund, Markus
    University of Skövde, School of Engineering Science.
    Hållfasthetssimulering av hydrauliska högtryckskopplingar2018Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Hydraulic FEM ½" high pressure couplings are studied with the purpose of establishing an effective methodology that can be used to predict the strength of the couplings. The methodology consists of finite element analyzes (FEA) and is validated by experimental pressure tests, performed on the FEM ½” couplings pairs.  Using FEA, the couplings solid mechanical behavior and maximum load ability can be viewed virtual, reducing the need for experimental tests and gives the potential for optimized products. The work is performed at Parker Hannifin AB in Skovde.

    Experimental tests are performed on 20 FEM ½” couplings pairs, to understand the solid mechanical behavior of the couplings until failure occurs, and to predict the maximum pressure that can be applied. The experimental structure and performance is based on the method Design of Experiments (DOE). Critical components are identified based on the results from the experimental tests, which are then studied more closely through FEA. The analysis are validated based on the applied material model, and data collected during the experimental tests.

    From the experimental tests it is shown that the components: ball cage, guide and plug housing are the components in which failure occur. In case of failure, two failure modes appear as common, that the ball cage is worn apart and that the guide burst, both types of failure modes occur at a similar pressure. The analysis for the guide and ball cage corresponds with the experimental outcomes. Differences occurs however when looked at the deformations, in which the plug housing shows the largest deviation when compared to the experimental results.

    The usage of FE-models appears to be appropriate for predicting and evaluating the mechanical strengths of the couplings during pressure loads. The analysis are however entirely dependent on the input data, where an incorrect material model generates incorrect results. The relationship is shown for the plug housing, which lack the mechanical properties related to curing processes.

  • 459.
    Vuoluterä, Fredrik
    et al.
    University of Skövde, School of Engineering Science.
    Carlén, Oliver
    University of Skövde, School of Engineering Science.
    Analysis of material flow and simulation-based optimization of transportation system: The combination of simulation and Lean to evaluate and design a transportation system2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis has been performed in cooperation with a Swedish manufacturing company. The manufacturing site of the company is currently implementing a new machine layout in one of its workshops. The new layout will increase the product flow to another workshop on the site. The goal of the thesis was to evaluate the current transportation system and suggest viable alternatives for the future product flow. By means of discrete event simulation these alternative solutions would be modelled and subsequently optimized to determine if their performance is satisfactory. An approximated investment cost of the solutions would also be estimated.

    By performing a literature review and creating a frame of reference, a set of relevant methodologies were selected to provide a foundation to the project. Following these methodologies, the current state of transportation was identified and mapped using Value Stream Mapping. Necessary data from the current flow was identified and collected from the company computer systems. This data was deemed partly inaccurate and further verification was needed. To this end, a combination of Genchi Genbutsu, assistance from onsite engineers and a time study was used to verify the unreliable data points. The data sets from the time study and the company data which was deemed valid were represented by statistical distributions to provide input for the simulation models.

    Two possible solutions were picked for evaluation, an automated guided vehicle system and a tow train system. With the help of onsite personnel, a Kaizen Event was performed in which new possible routing for the future flow was evaluated. A set of simulation models portraying the automated guided vehicle system and the tow train system were developed with the aid of simulation software. The results from these models showed a low utilization of both systems. A new set of models were developed, which included all the product flows between the workshops. The new flows were modelled as generic pallets with the arrival distribution based on historical production data. This set of models were then subject for optimization with regard to the work in process and lead time of the system. The results from the optimization indicates the possibility to reduce the overall work in process by reducing certain buffer sizes while still maintaining the required throughput. These solutions were not deemed to be ready for implementation due to the low utilization of the transportation systems. The authors instead recommend expanding the scope of the system and including other product flows to reach a high utilization.

  • 460.
    Walander, Tomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Chalmers University of Technology.
    Influences of temperature, fatigue and mixed mode loading on the cohesive properties of adhesive layers2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns some aspects that have influence on the strength of adhesive layers. The strength is determined by the stress deformation-relation of the layer. This relation is also referred to as cohesive law. The aspects having influence on the cohesive laws that are studied in this work are temperature, fatigue, multi-axial fatigue and mixed mode loading.

    For each aspect, a model is developed that can be used to describe the influence of the aspects on the cohesive laws numerically, e.g. by using the finite element method. These models are shown to give good agreement with the experimental results when performing simulations that aims at reproducing the experiments. For the aspect of temperature, a FE-model is suggested that can be used to simulate the mechanical behaviour in pure mode loadings at any temperature within the evaluated temperature span. Also, a damage law for modelling high cycle fatigue in a bonded structure in multi-axial loading is presented. Lastly, a new experimental set-up is presented for evaluating strength of adhesives during mixed mode loading. The set-up enables loading with a constant mode-mix ratio and by the experimental results, a potential model for describing the mechanical behaviour of the evaluated adhesive is presented.

  • 461.
    Walander, Tomas
    et al.
    University of Skövde, School of Technology and Society.
    Biel, Anders
    University of Skövde, School of Technology and Society.
    Stigh, Ulf
    University of Skövde, School of Technology and Society.
    An evaluation of the temperature dependence of cohesive properties for two structural epoxy adhesives2012In: 19th European Conference on Fracture, Kazan Scientific Centre of the Russian Academy of Sciences , 2012Conference paper (Refereed)
    Abstract [en]

    Cohesive modelling provides a more detailed understanding of the fracture properties of adhesivejoints than provided by linear elastic fracture mechanics. A cohesive model is characterized by astress-deformation relation of the adhesive layer. This relation can be measured experimentally.Two parameters of the stress-deformation relation are of special importance; the area under thecurve, which equals the fracture energy, and the peak stress. The influence of temperature of theseparameters is analyses experimentally and evaluated statistically for two structural epoxy adhesivesin the span from of -40°C to +80°C. The adhesives are used by the automotive industry and atemperature span below the glass transition temperature is considered. The results show that thattemperature has a modest influence on the adhesives Mode I fracture energy. For one of theadhesives, the fracture energy is independent of the temperature in the evaluated temperature span.In mode II, the influence of temperature is larger. The peak stresses decreases almost linearly withan increasing temperature in both loading cases and for both adhesives.

  • 462.
    Walander, Tomas
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Stigh, Ulf
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Temperature dependence of cohesive laws for an epoxy adhesive in Mode I and Mode II loading2013In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 183, no 2, p. 203-221Article in journal (Refereed)
    Abstract [en]

    The influence of the temperature on the cohesive laws for an epoxy adhesive is studied in the glassy region, i.e. below the glass transition temperature. Cohesive laws are derived in both Mode I and Mode II under quasi-static loading conditions in the temperature range C. Three parameters of the cohesive laws are studied in detail: the elastic stiffness, the peak stress and the fracture energy. Methods for determining the elastic stiffness in Mode I and Mode II are derived and evaluated. Simplified bi-linear cohesive laws to be used at any temperature within the studied temperature range are derived for each loading mode. All parameters of the cohesive laws are measured experimentally using only two types of specimens. The adhesive has a nominal layer thickness of 0.3 mm and the crack tip opening displacement is measured over the adhesive thickness. The derived cohesive laws thus represent the entire adhesive layer as having the present layer thickness. It is shown that all parameters, except the Mode I fracture energy, decrease with an increasing temperature in both loading modes. The Mode I fracture energy is shown to be independent of the temperature within the evaluated temperature span. At C the Mode II fracture energy is decreased to about 2/3 of the fracture energy at C. The experimental results are verified by finite element analyses.

  • 463.
    Walander, Tomas
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Eklind, Alexander
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Carlberger, Thomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Stigh, Ulf
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Fatigue damage of adhesive layers: experiments and models2014In: Procedia Materials Science, ISSN 2211-8128, Vol. 3, p. 829-834Article in journal (Refereed)
    Abstract [en]

    Mode I fatigue crack growth at load levels close to the threshold is studied with the aim of improving the understanding of the fatigue properties. We also aim at identifying a suitable damage evolution law for large-scale simulation of built-up structures. A fatigue test rig is designed where up to six specimens are tested simultaneously. Each specimen is evaluated separately indicating the specimen-to-specimen variation in fatigue properties. A rubber-based and a PUR-based adhesive are tested. The two adhesives represent adhesives with very different material properties; the rubber adhesive is a stiff structural adhesive and the PUR adhesive is a soft modular adhesive. The experiments are first evaluated using a traditional Paris’ law approach. Inspired by an existing damage evolution law, a modified damage evolution law is developed based on only three parameters. The law is implemented as a user material in Abaqus and the parameters are identified. The results from simulations show a very good ability to reproduce the experimental data. With this model of fatigue damage, a zone of damage evolves at the crack tip. The extension of this zone depends on the stiffness of the adherends; stiffer adherends leads to a larger damage zone. This means that the rate of crack growth depends on the stiffness of the adherends. Thus, not only the state at the crack tip governs the rate of crack growth. This is in contrast to the results of a model based on Paris’ law where only the state at the crack tip, through the energy release rate, governs the rate of crack growth. This indicates that the threshold value of the energy release rate may depend on the stiffness of the adherends.

  • 464.
    Walander, Tomas
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Eklind, Alexander
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Carlberger, Thomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Stigh, Ulf
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Rietz, Andreas
    Scania STC, Södertälje, Sweden.
    Prediction of mixed-mode cohesive fatigue strength of adhesively bonded structure using Mode I data2016In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 66, p. 15-25Article in journal (Refereed)
    Abstract [en]

    A cohesive zone model is presented for analyzing the fatigue life of an adhesive joint in the range of 104–106 load cycles. The parameters of the model are derived from Mode I double cantilever beam experiments. Fatigue experiments with adhesively joined components from the automotive industry are performed, and the results from the experiments are compared to the results of simulations. The error in the predicted fatigue strength is of the same order as the statistical deviation of the fatigue experiments, indicating that the simulation method produces acceptable predictions of the fatigue strength for applications in e.g. early product development.

  • 465.
    Wallin Johansson, Daniel
    University of Skövde, School of Engineering Science.
    KARTLÄGGNING AV VÄRDEFLÖDEOCH IDENTIFIERING AV SLÖSERIERFÖR ÄGGPRODUKTION2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Dava Foods in Skara has been the industry for this final year project where they processing egg in different conditions. For this project has the process where they manufacture protein drinks as they sold to the stores been in focus. The main goals for the project were to bring a value streaming map of the current state of the production and suggest improvements based on this map. The second goal was to find which types of wastes that occur and find improvements.

    To create an understanding of the existing process, an analysis was made where the stream was observed. Observations and interviews were used to collect data for the project. The analysis of the exciting process has been based on for the implementation stage.

    During the implementation stage was different tools used to collect data. PDCA has been a tool where was followed during the whole project. The value streaming map has been a central tool which was used to bring out a value streaming map. To collect the times which was needed for the value streaming map a stopwatch was used.

    The project result in different improvement proposal where many of the proposals included was to automate the processes. One solution was to change the operator against a robot cell which would streamline the process which would result in a lower throughput. Change machine was another solution where many stops occur. A full automation concept was suggested to combine these two suggestions, where both a robot and a machine was bought. The last suggestion of the value streaming map was about to just produces one product at a time. Within the wastes were three suggestions given where maintenance was the best solution to reduce the wastes. To determine which one of the suggestions was the best solution a pick chart was used to priority how hard the suggestion was and benefit.

    The conclusion was to purchasing the machine where stops frequently occur. This suggestion would create a higher efficiency in the production at the same time where the condition about price would give the best solution. Improvements of maintenance would also result as the best solution to increase the efficiency for the current machines and reduce the number of stops.

  • 466.
    Wang, Lihui
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Collaborations towards adaptive manufacturing2012In: Proceedings of the 2012 IEEE 16th International Conference on Computer Supported Cooperative Work in Design (CSCWD) / [ed] Liang Gao, Weiming Shen, Jean-Paul Barthès, Junzhou Luo, Jianming Yong, Wenfeng Li & Weidong Li, IEEE conference proceedings, 2012, p. 14-21Conference paper (Refereed)
    Abstract [en]

    This paper presents a new approach for real-time collaborations in adaptive manufacturing, including web-based remote monitoring and control of an industrial robot, and active collision avoidance for human-robot collaborations. It is enabled by using virtual 3D models driven by real sensor data and depth images of human operators. The objectives of this research are to significantly reduce network traffic needed for real-time monitoring over the Internet and to increase the human safety in a human-robot coexisting environment. The results of a case study show that the approach consumes less than 1% of network bandwidth of traditional camera-based methods, and is feasible and practical as a web-based solution.

  • 467.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2012Collection (editor) (Refereed)
  • 468.
    Wang, Lihui
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    International Journal of Manufacturing Research2012Collection (editor) (Refereed)
  • 469.
    Wang, Wei
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Bandaru, Sunith
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Sánchez de Ocãna Torroba, Adrian
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Improved Human-Robot Collaboration Through Simulation-Based Optimization2019In: Advances in Manufacturing Technology XXXIII: Proceedings of the 17th International Conference on Manufacturing Research, incorporating the 34th National Conference on Manufacturing Research, 10–12 September 2019, Queen’s University, Belfast, UK / [ed] Yan Jin, Mark Price, Amsterdam: IOS Press, 2019, Vol. 9, p. 153-158, article id 10.3233/ATDE190027Conference paper (Refereed)
    Abstract [en]

    In order to pursue the dream combination of human flexibility and robot automation, human robot collaboration (HRC) is increasingly being investigated through academic research and industrial scenarios. HRC involves several challenges ranging from safety and comfort of the human to process efficiency and cost of robot operation. Achieving the right balance between these aspects is critical to implementing a safe, profitable and sustainable HRC environment. In this paper,we propose the use of simulation-based optimization (SBO) for assembly task allocation and scheduling for a HRC working cell in which an industrial robot assists a human worker. The list of product assembly operations are classified according to the capability of human worker and robot, and the sequencing constraints on them are the initial inputs of the method. The operators’ ergonomic load scores and cycletime of the assembly process are achieved by simulation. The optimized solutions are sorted to find the trade-offs between ergonomics and cycle time. We demonstratethe feasibility of the proposed approach through an industrial case study.

  • 470.
    Wenäll, Johan
    University of Skövde, School of Technology and Society.
    Högskolan i Skövde tränar inför IPMA-certifiering2012In: Projektvärlden, ISSN 1652-3016, no 3, p. 29-29Article in journal (Other (popular science, discussion, etc.))
  • 471.
    Werner, Elin
    University of Skövde, School of Engineering Science.
    Materialanalys & optimering av hydrauliska högtryckskopplingar med hjälp av simuleringar2018Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Optimizing the burst pressure with finite element analysis is done on the FEM ½” coupling at Parker Hannifin AB. The critical components which is the ball cage, guide and plug housing are in focus. A more accurate material analysis is done to make a more real-based data of the material in the coupling.  

    After being in contact with the company that performs the hardening of the component, the entire plug housing is assumed to be hardened. For more information about material data, static pressure test is performed on a coupling. The measured strains from the tests are compared to the strains in the simulations. The tensile strength and hardness coefficient on the guide and ball cage can be adjusted slightly from the tests, but the result has several uncertainties. 

    The number of balls can be reduced, numbers of balls between 15 and 12 are investigated at request from the company. Analysis of how hardening of the material for the guide is done and hardening of the surface for the plug housing. 

    The smallest deformation occurs when hardening the guide. The ball cage clearly demonstrated minor deformations and stresses as the number of balls is reduced from 15 to 12 balls in the coupling. To reduce the burst pressure on the plug housing, it is recommended to harden the surface with a 27 % harder surface than the current. Due to estimated values of material data on hardened surface, more information is needed to determine the thickness needed on the surface of the hardening when having 12 balls in the coupling. 

  • 472.
    Wiktorsson, Magnus
    et al.
    KTH Royal Insitute of Technology, Dept of Sustainable Production Development, Södertälje, Sweden.
    Noh, Sang Do
    Sungkyunkwan University, Dept of Industrial Engineering, Suwon, South Korea.
    Bellgran, Monica
    KTH Royal Insitute of Technology, Dept of Sustainable Production Development, Södertälje, Sweden.
    Hanson, Lars
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Scania CV, Global Industrial Development, Södertälje, Sweden.
    Smart Factories: South Korean and Swedish examples on manufacturing settings2018In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 25, p. 471-478Article in journal (Refereed)
    Abstract [en]

    What constitutes a company's capabilities to develop a Smart Factory? South Korean and Swedish perspectives are here illustrated by company examples of smart factory solutions and related strategic aspects of their digitalization. It is concluded that the "smart-factory-capability" of a manufacturing company is integrated with its corporate production systems and includes perspectives on application areas, value adding processes as well as enabling technologies. It is furthermore challenged by the transformational inabilities of legacy systems. By its concrete examples is use and financial benefits, the paper contributes to the definition of the smart factory and its corresponding development scheme. 

  • 473.
    Wingren, Magdalena
    University of Skövde, School of Technology and Society.
    Windscreen study using a free moving headform: An investigation of windscreen behaviour when subjected to headform impact2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Pedestrian protection performance becomes more and more in focus for the car manufactures and systems to reduce injury risk are under development. A wider understanding of both the present and the future windscreen performance in free moving headform testing is needed to optimize these systems. The purpose of this thesis was therefore to learn and understand windscreen behaviour when subjected to head impact and to gain knowledge of CAE status for head impact in windscreens from a pedestrian point of view.

    A literature review concluded that there are different ways to model a windscreen. It was found that the computer material models for laminated windscreen glass were not capable of fully representing the behaviour of this material under all impact conditions, particularly the non-linear behaviour after fracture or failure.

    Experimental testing on three different windscreen models, with a free moving headform in a horizontal impactor, has been performed. Test set up was according to Euro NCAP pedestrian testing protocol and three different windscreen angles were tested. The parameter investigated was curvature and HIC and deformation depth on the windscreen were used as evaluation tools. Deformation was measured with a laser positioned behind the windscreen at impact. Film analysis and integration of headform accelerations were used as comparison. The testing concludes that different curvature alone will not have a big influence on HIC and deformation.

     

    Keywords: PVB laminated windscreen, pedestrian, impact, free moving headform

  • 474.
    Wänerberger, Alexander
    et al.
    University of Skövde, School of Engineering Science.
    Said, Sayyed Hamid
    University of Skövde, School of Engineering Science.
    Lagerstyrning och prognostisering av råmateriallagret2014Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Production to customer order usually requires keeping a supply warehouse. Increased customer demands for short lead-times require that materials must be in stock. This result in increasing stock levels in a company leads to more capital tied up and simultaneously leads to poorer yields. To avoid keeping a large storage warehouse whilst keeping a good service requires an effective inventory control.

    The purpose of this project is to find out how the demand looks like in the current situation of the company and to develop an appropriate forecasting method and calculation model against a certain pace for inventory control. The methods mentioned in this work are the ABC analysis, calculation of safety stock and forecasting methods.

    The results from this work will answer the objectives of the project aims. A variety of analyzes and experiments shall be used to investigate what type of forecasting method that the company should use. The methods and theories raised in the report also aims to be used by similar companies. The aim of the selected forecasting method is also to lead to a better base, from which better forecast precision is one part in order to improve the inventory management. This has, as far as possible, been put in relation to the working methods used in the company today. Some of the work has been to find out how much demand changes during the lead times, i.e. from the ordering of raw material until the material is in the raw material stock. This has also been used to compare forecasting methods against the present approach.

    Because the company wants to expand its production, a calculation model has also been developed. This model indicates the inventory level to a desired pace, i.e. demand level.

  • 475.
    Xia, Johnny
    University of Skövde, School of Engineering Science.
    A NEW STUDY OF UNBALANCED PRODUCTION LINE WITH OPTIMIZATION2018Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project is a continuous research of a topic well-known in the literature, namely, the performance study of unbalanced unpaced production system. In the literature, there were many studies that investigated the statistical outputs of an unbalanced production line using simulation. This project focuses on researching the outputs like average buffer level and idle time that are rarely studied in previous research by using optimization tools from discrete event simulation software FACTS.The models used in the article (Shaaban & McNamara, 2009) have been used as a guideline during the development of the simulation models for this project. Two simulation models were created, each using different discrete event simulation software, namely FACTS analyzer and Plant simulation. Those simulation models fulfills its role in verification & validation stage, with their statistical outputs compared to each other and with Shaaban and McNamara’s results. After verification & validation comes optimization of those simulation models, by using optimization tools from FACTS.The research area expanded during the optimization phase. Originally Shaaban et.al analyzed unbalanced production line with one fixed value of coefficient of variation. In order to expand the view on the properties of an unbalanced production line, three more coefficient variation were added with total of four in this project. As a result, 12 optimization results were created at the end of this project. Each optimization has 30 000 iterations to ensure its convergence.The first step of analysis is done by locating all Pareto-optimal solutions with optimization tools in FACTS. The raw data of all solutions are later transferred and converted into EXCEL files. Using scatter graph and putting all outputs against each other in EXCEL, it creates visual graph that can be used to analyze and to investigate interesting behavior in an unbalanced production line.The analysis on the optimization results showed several interesting behaviors from production line with different settings. One being that if a production line possess worse coefficient of variation than its competition. By raising the inter-stage buffer level of the production line with inferior coefficient of variation, it can achieve the same level, if not greater outputs than its competitor who possess better coefficient of variation. The other interesting behavior are optimization results with highest outputs in regard of either idle time or average buffer level, with deep analyzation using optimization tools from FACTS. Certain operation time pattern and inter-stage buffer pattern could be observed from those results.

  • 476.
    Yousefi, Milad
    et al.
    Department of Production and Transportation Engineering, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
    Yousefi, Moslem
    Department of Mechanical Engineering, Islamic Azad University, Roudehen Branch, Roudehen, Iran.
    Fathi, Masood
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Fogliatto, Flavio
    Department of Production and Transportation Engineering, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
    Patient visit forecasting in an emergency department using a deep neural network approach2019In: Kybernetes, ISSN 0368-492X, E-ISSN 1758-7883Article in journal (Refereed)
    Abstract [en]

    This study aims to investigate factors affecting daily demand in an emergency department (ED) and to provide a forecasting tool in a public hospital for horizons of up to 7 days.In this study, first the important factors to influence the demand in EDs were extracted from literature then the relevant factors to our study are selected. Then a deep neural network is applied for constructing a reliable predictor.Although many statistical approaches have been proposed for tackling this issue, better forecasts are viable through employing the abilities of machine learning algorithms. Results indicate that the proposed approach outperforms statistical alternatives available in the literature such as multiple linear regression (MLR), autoregressive integrated moving average (ARIMA), support vector regression (SVR), generalized linear models (GLM), generalized estimating equations (GEE), seasonal ARIMA (SARIMA) and combined ARIMA and linear regression (LR) (ARIMA-LR).We applied this study in a single ED to forecast the patient visits. Applying the same method in different EDs may give us a better understanding of the performance of the model. The same approach can be applied in any other demand forecasting after some minor modifications.To the best of our knowledge, this is the first study to propose the use of long short-term memory (LSTM) for constructing a predictor of the number of patient visits in EDs.

  • 477.
    Zetterberg, Stefan
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, School of Technology and Society.
    Into, Camilla
    University of Skövde, School of Technology and Society.
    Transitlager som en strategi i ett globalt distributionssystem2009Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Nuförtiden är det stora flertalet försörjningskedjor internationella till sin karaktär och trenden går alltmer mot fokuserade fabriker. Det innebär att ett fåtal fabriker som var och en fokuserar på ett fåtal produkter tar hand om produktionen för hela världsmarknaden. Då tillverkningen sker på få utvalda platser och marknader världen över ska försörjas ifrån dessa krävs ett globalt distributionssystem som ska klara av att hantera den ökade konkurrensen, kundernas krav på kortare ledtider och den ökade differentieringen av produkter.

    Det finns olika strategier för att hantera ett globalt distributionssystem. Syftet med denna uppsats är att utreda om en transitlagerstrategi kan vara ett konkurrenskraftigt komplement eller alternativ till de mer vanligt förekommande distributionsstrategierna. Studien har gjorts genom att skapa ett teoretiskt ramverk vilket beskriver hur det globala distributionssysteme kan hanteras. Med förutsättningen att företagen idag har ett globalt distributionssystem måste de kunna distribuera sina varor över hela världen och teorin behandlar tre distributionsstrategier för att hantera detta och det är centraliserad distributionsstrategi, decentraliserad distributionsstrategi och transitlagerstrategi. De olika distributionsstrategiernas egenskaper samt för- och nackdelar beskrivs för att avgöra i vilka affärsmiljöer respektive strategi lämpar sig.

    Det teoretiska ramverket behandlar hur företag kan välja mellan och kombinera de olika distributionsstrategierna utifrån deras förutsättningar att produkterna ska nå många marknader från ett fåtal fabriker. För att underlätta valet av distributionsstrategi har en matris konstruerats i ramverket. Matrisen bygger på ett antal utvalda variabler vilka är viktiga att ta hänsyn till. Avslutningsvis när en strategi eller en kombination av strategier är vald ska teorin behandla hur företagen praktiskt kan arbeta med de olika strategierna.

    Empirin kommer att redogöra för två fallstudier där de olika företagen är Etylenaminer och Eka Chemicals. Det kommer att beskrivas hur deras distributionssystem ser ut idag, vilka distributionsstrategier som de använder samt hur de arbetar praktiskt med dem.

    I analysen har det teoretiska ramverket ställts emot den insamlade empirin för att utreda om transitlagerstrategin kan vara ett konkurrenskraftigt komplement till den centrala distributionsstrategin och den decentraliserade distributionsstrategin. Den slutsats som forskningen leder fram till är att det finns mer än ett sätt att strukturera distributionssystemet på och genom det bli framgångsrik på en global marknad. Oavsett vilket distributionssystem ett företag har byggt upp kan transitlagerstrategin utgöra ett bra komplement eller alternativ till den centraliserade distributionsstrategin och den decentraliserade distributionsstrategin för att vinna konkurrensfördelar på marknaderna. Transitlagerstrategin kan bland annat ge upphov till kortare ledtider än vad som kan uppnås med den centraliserade distributionsstrategin och mindre kapitalbindning än vad tillämpningen av den decentraliserade distributionsstrategin ger genom att produkten inte behöver lagras lokalt för att erbjuda kunden korta ledtider. Forskningen visar vidare på att det tar mycket lång tid att utveckla en renodlad transitlagerstrategi men att företagen redan i de tidiga utvecklingsfaserna av strategin kan tillgodogöra sig stora konkurrensfördelar.

  • 478.
    Zhang, Xiaoyang
    et al.
    Faculty of Engineering, Environment and Computing, Coventry University, Coventry, United Kingdom.
    Lu, Xin
    Faculty of Engineering, Environment and Computing, Coventry University, Coventry, United Kingdom.
    Wang, Sheng
    Faculty of Engineering, Environment and Computing, Coventry University, Coventry, United Kingdom.
    Wang, Wei
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Li, Weidong
    Faculty of Engineering, Environment and Computing, Coventry University, Coventry, United Kingdom.
    A multi-sensor based online tool condition monitoring system for milling process2018In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 72, p. 1136-1141Article in journal (Refereed)
    Abstract [en]

    Tool condition monitoring has been considered as one of the key enabling technologies for manufacturing optimization. Due to the high cost and limited system openness, the relevant developed systems have not been widely adopted by industries, especially Small and Medium-sized Enterprises. In this research, a cost-effective, wireless communication enabled, multi-sensor based tool condition monitoring system has been developed. Various sensor data, such as vibration, cutting force and power data, as well as actual machining parameters, have been collected to support efficient tool condition monitoring and life estimation. The effectiveness of the developed system has been validated via machining cases. The system can be extended to wide manufacturing applications.

  • 479.
    Zia, Muhammad Irfan
    et al.
    University of Skövde, School of Technology and Society.
    Cortés Mora, Felipe
    University of Skövde, School of Technology and Society.
    Automation of packing process2008Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The design work that precedes the automation of a process is not an easy job. Each one of the variables and possible risks involved in process must be carefully considered before implement the final design as well the requirements in performance and cost. However automate a dangerous, inefficient or just uncomfortable task entails many benefits that make up for the long period of design process. A well automated line will benefit the production with quality, productivity and capacity among other profits. In this project the immediate objective is to automate the “SANDFLEX Hacksaw blades” packaging process in the plant that SNAEurope owns in Lidköping. Actually the packing is completely manual. One operator packs the blades into the boxes meanwhile one more operator loads and unloads the packing station with empty and full boxes respectively. The task is both, tiring and uncomfortable for the operators as well inefficient for the company since the production rate is limited.

    Analyzing and observing carefully product and process, different theories and strategies to achieve the goal were developed. Three are the possible solutions to solve the problem, with different levels of automation and technologies. The robotic solution uses an articulated robot to perform all the tasks; the hybrid solution uses pneumatic devices to pack the blades and an articulated robot to support the station loading and unloading the boxes. Finally the pneumatic solution uses only pneumatic devices, which hold, open and close, push box and blades using airpower; a few sensors detect positions and states, since a PLC coordinates and controls all process. By means of discussing these solutions with the company’s engineers and workers, after a deep literature study and two test of performance, was it possible to select the most suitable solution to accomplish the packaging task. The pneumatic solution is cheap and simple, but at the same time robust and reliable. This design performs the packaging task efficiently and fast. And more important, the operator passes from pack manually the blades to monitor the process.

  • 480.
    Zini, Omar
    University of Skövde, School of Technology and Society.
    A simplified forging simulation tool: validation with finite element method2013Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Nowadays, the forging industry has a great importance in the fabrication of metallic parts. Therefore, new theoretical models, or modifications to others already existing, continuously appear to improve the process. New investigations culminated, recently, in equations designed to obtain the necessary pressure to forge a part. The purpose is to have a fast, not expensive and efficient alternative to the numerical methods in such calculation. With the double intention of divulgating this new theory created in the University of Málaga (Spain) and confirming its validity, it is interesting to carry out a comparison with the finite element method. In this comparison, geometrical factors relative to the workpiece (part subjected to forging) and the friction coefficient come into play. The goal is then to find validity ranges in the equations for the variables previously mentioned, with the aim to delimit those forging situations in which they could be applied. The implementation of these variables into the commercial FE-code Abaqus is simple, although two aspects arise: the meshing and the correct modeling of the contact between the workpiece and the upper die. The limitation of the Abaqus Student Version (used throughout the analyses) in the allowed number of nodes, prevented performing sufficiently dense meshes. Many alternatives are investigated that, unfortunately, do not show any satisfactory result for the simulation of the process. Performing forging simulations is quite complex and requires a great knowledge in the field and an extraordinary knowledge of how different elements work in large plastic strain. However, this project leaves a collecting data method and a procedure to determine the initial geometry of the workpiece to ensure plastification and to reach a determined shape factor after the forging. The most important is that the way to further analyses has been cleared by confirming the suitability for certain parameters in the simulation (element type, non-linear geometry, contact model, etc.). The recommendation for future simulation efforts is to use ALE (Arbitrary Lagrangian-Eulerian) adaptive meshing.

  • 481.
    Öberg, Daniel
    University of Skövde, School of Engineering Science.
    Utveckling av ett cykelskåp anpassat för stadsmiljö2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The project began as an open question in collaboration with a consulting company in product development to develop a more secure parking for bicycles. Therefore, a comprehensive feasibility study was performed to evaluate the bicycle values and to see potential development opportunities for different types of bicycle parking. Blidsberg mekaniska is a company that manufactures bicycle parking and other types of outdoor environment products. They were involved in the work and wanted to expand their range with a new bike box. The designprocess started with a marketreasearch with the aim to analyze cycle parks in a pre-study. During the pre-study demands was researched and formed a requirement specification. The creative work in the development of a new cycle park was helped by many creative methods that generated many concepts that later was compared in a matrix. The final concept was able to compete with the existing solutions. The result was a combination of already existing solutions. The bicycle locker does not take up more space than is necessary for most bicycles to fit in. The bicycle locker is modularly adapted and can therefore be placed more space efficiently in different places. A light indication on the handle indicates whether the bicycle locker is free or occupied and opened with a tag that is scanned on a RFID-reader.

  • 482.
    Öhnström, Magnus
    et al.
    University of Skövde, School of Engineering Science.
    Göhlin, Victor
    University of Skövde, School of Engineering Science.
    Förbättring av passivdämpande hörselskydd2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Magnus Öhnström and Victor Göhlin are two design engineer students from the University of Skövde. To obtain their bachelor in engineering they have completed a study for Hellberg Safety to improve the sound dampening effect in their passive earmuffs. The goal is a standard shell that can be optimized for different grades of sound dampening. In order to obtain knowledge a pilot study was performed. This included an analysis of one of the major competitor’s products. In order to reach the goal, the shell, absorber and cushion had to be examined. Modifications made were evaluated with an Acoustic Test Fixture (ATF) located in Hellbergs sound lab. Different modifications were combined, evaluated and sent to Germany for further evaluation. From the given results parts of the shell were further developed.

78910 451 - 482 of 482
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