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  • 401.
    Skoogh, Anders
    et al.
    Chalmers University of Technology, Gothenburg, Sweden.
    André, Jean-Patrick
    Chalmers University of Technology, Gothenburg, Sweden.
    Dudas, Catarina
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Svensson, Jacob
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Urenda Moris, Matias
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Johansson, Björn
    Chalmers University of Technology, Gothenburg, Sweden.
    An automated approach to input data management in discrete event simulation projects: A proof-of-concept demonstrator2007In: EUROSIM 2007, 2007Conference paper (Refereed)
    Abstract [en]

    Despite the fact that Discrete Event Simulation (DES) is claimed to be one of the most potent tools for analysis and optimization of production systems, industries worldwide have not been able to fully utilize its potential. One reason is argued to be that DES projects are not time efficient enough due to extensive time consumption during the input data phases. In some companies, input data is totally missing, but even in projects where data is available it usually takes a considerable amount of time to analyze and prepare it for use in a simulation model. This paper presents one approach to the problem by implementing a software that automates several steps in the input data process such as extracting data from a database, sorting out the information needed and fitting the data to statistical distributions. The approach and the software have been developed based on a case study at Volvo Trucks in Gothenburg, Sweden. The work presented in this paper is part of a more comprehensive project called FACTS. The project scope is to develop methods and IT-tools for conceptual plant development. 

  • 402.
    Stigh, Ulf
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Applications of equilibrium of configurational forces for the measurement of cohesive laws2016In: Proceedings ECCM17: 17th European Conference on Composite Materials Munich, Germany, 26-30th June 2016, 2016Conference paper (Refereed)
    Abstract [en]

    A methodology to develop experimental methods to measure cohesive laws is introduced. This methodology is based on the property of all configurational forces equilibrium acting on a specimen to be in equilibrium. Two applications are given. The first shows a method to measure the cohesive law for shear representing the mechanical behaviour of an adhesive layer. The second application is a method to measure the cohesive law for the formation of a kink-band in a unidirectional composite. It is concluded that the methodology is critically dependent on the ability to associate a pseudopotential to the inelastic properties of the deforming material where the fracture process takes place. The importance to clearly identify the material that is modelled with the cohesive zone is also stressed.

  • 403.
    Stigh, Ulf
    University of Skövde, School of Technology and Society.
    Continuum Damage Mechanics and the Life-Fraction rule2006In: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 73, no 4, p. 702-704Article in journal (Refereed)
    Abstract [en]

    This paper gives a short review of two different methods for life prediction at high temperature; namely continuum damage mechanics (CDM) and the linear life-fraction rule (LFR). It is well known that the class of CDM theories with a separable evolution law gives a life prediction in accordance with the LFR. However, it appears to be an open question if this is a necessary condition. It is here shown that in order for a CDM theory to comply with the LFR it must have a separable evolution law. That is, if we can assume that a material follows the LFR, it is necessary to chose a separable evolution law for this material. The reverse is also true, to get a life-fraction different from unity, we must chose a nonseparable evolution law.

  • 404.
    Stigh, Ulf
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Effects of strain rate on the cohesive properties and fracture process of a pressure sensitive adhesive2018In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 203, p. 266-275Article in journal (Refereed)
    Abstract [en]

    Pressure sensitive adhesives provide high toughness at low stress and stiffness. These properties are beneficial for bimaterial bonding. In the present study the tape is modelled with a cohesive layer characterized by a cohesive law. This is suitable for FE-analysis of bonded structures. The cohesive law is measured using a method based on the path independent property of the J-integral. Complementing an earlier study, we here focus on influences of loading rate on the properties of the pressure sensitive adhesive. Transparent PMMA substrates are used with the transparent tape in Double Cantilever Beam specimens. The transparency of both the tape and the substrates provides the possibility of in-situ studies of the fracture process. The results indicate that the fracture energy levels off at about 1 kN/m for small loading rates. Moreover, the cohesive law also appears to level off below an engineering strain rate of about 2 s-1. The cohesive law contains two peak stresses. The first is associated with the nucleation of cavities in the tape. This occurs at a stress level comparable to the critical stress associated with an unbonded growth rate of a spherical cavity in rubber. The second peak stress is associated to the breaking down of walls formed between the fully developed cavities. This process precedes the final fracture of the tape. It also appears as nucleation of cavities is influenced by the strain rate where slower rates give more time for cavities to nucleate. This results in larger cavity density at smaller loading rates. The results also indicate a similarity of the effects of loading rate and ageing of the macroscopic properties of the present pressure sensitive adhesive.

  • 405.
    Stigh, Ulf
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Shear properties of an adhesive layer exposed to a compressive load2014In: Procedia Materials Science, ISSN 2211-8128, Vol. 3, p. 1626-1631Article in journal (Refereed)
    Abstract [en]

    Adhesive joints are designed to transfer load in shear since both the fracture energy and the fracture stress are larger in shear than in peel. Shear deformation is isochoric, however, the fracture process involves nucleation and growth of a multitude of slanted microcracks. In order to grow, these microcracks open up. Thus, adhesive layers show a tendency to deform in peel during shear fracture. This opening is localized to the fracture process zone and the adherends have to separate locally over the process zone to allow for the adhesive to swell. Depending on the stiffness of the adherends, the opening mode is more or less prohibited. With stiffer adherends, the opening is obstructed more efficiently than with softer adherends. Micromechanical studies indicate that the constraints of the peel deformation during shear loading have a profound influence on the strength of the joint. In the present study, we compress the process zone during experiments. Repeated experiments with ENF-specimens are performed. A compressive force is applied on the first part of the adhesive layer by use of a pneumatic cylinder. The experiments are evaluated using the path independent J-integral. Together with measurements of the shear and peel deformation of the adhesive layer at the start of the layer, the complete shear stress vs shear deformation relations are evaluated. It is shown that the inhibited peel deformation gives a substantial increase of the fracture energy

  • 406.
    Stigh, Ulf
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Studies of fracture in shear of a constrained layer2017In: Advanced Problems in Mechanics: Proceedings of the XLV Summer School Conference / [ed] Dmitri A. Indeitsev & Anton M. Krivtsov, St Petersburg: Institute for Problems in Mechanical Engineering RAS , 2017, p. 420-428Conference paper (Refereed)
    Abstract [en]

    Cracks normally propagate in the opening mode associated with a state of local symmetry at a crack tip. However, the micro- or macrostructure of a material or structure sometimes forces cracks to propagate in a shearing mode. Irrespective of the actual material studied, fracture in shear is frequently asso- ciated with the formation of a large number smaller sigmoidal-shaped cracks in the propagation direction of the major crack. Propagation of the major shear crack is accomplished by coalescing the sigmoidal-shaped cracks. Ex- periments show that the formation of sigmoidal cracks due to shear loading leads to a normal separation of the joined substrates. Theoretical studies show that constraining the local opening of the sigmoidal cracks increases the frac- ture resistance for the propagation of the major crack. In the present study, experiments with a ductile adhesive loaded in shear and where the normal sep- aration is constrained are presented. The experiments are evaluated using the path independent J-integral. The associated cohesive law shows that consid- erable normal compressive stress develops in the adhesive during macroscopic shear loading. It is also concluded that by ignoring the normal separation in the evaluation of the experiments, the strength of the adhesive is underesti- mated. Thus, the procedure developed in earlier studies is conservative from a strength analysis perspective. The present technique might be possible to extend to other materials to reveal their properties in shear fracture.

  • 407.
    Stigh, Ulf
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    Department of Wind Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark.
    Svensson, Daniel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Cohesive zone modelling and the fracture process of structural tape2016In: Proceedia Structural Integrity, ISSN 2452-3216, Vol. 2, p. 235-244Article in journal (Refereed)
    Abstract [en]

    Structural tapes provide comparable toughness as structural adhesives at orders of magnitude lower stresses. This is potentially useful to minimize the effects of differences in thermal expansion in the joining of mixed materials. The strength properties are modelled using the cohesive zone model. Thus, a cohesive zone represents the tape, i.e. stresses in the tape are transmitted to the substrates through tractions determined by the separations of the surfaces of substrates. This simplification allows for structural analysis of large complex structures. The relation between the traction and the separation is measured experimentally using methods based on the path independence of the J-integral. Repeated experiments are performed at quasi-static loading. A mixed mode cohesive law is adapted to the experimental data. The law is implemented as a UMAT in Abaqus. Simulations show minor thermal distortions due to thermal loading and substantial structural strength in mechanical loading of a mixed material structure.

  • 408.
    Stigh, Ulf
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Biel, Anders
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Walander, Tomas
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Fracture of Adhesive Layers in Mode II2012In: Proceedings of the 19th European Conference on Fracture, Kazan Scientific Centre of the Russian Academy of Sciences , 2012Conference paper (Refereed)
    Abstract [en]

    Measuring fracture properties of adhesives in Mode II is often problematic. Indeed, no method can today be regarded as established by the community. In this paper a number of methods are presented. Experiments show that the evaluated properties of the same adhesive sometime vary considerably with the choice of specimen. Even just modest variations in loading conditions using the same specimen can yield considerable variation in the evaluated properties. Sources for these deficiencies are identified.

    It has long been understood that Mode II testing using the end-notched flexure specimen (ENF) is conditionally stable. That is, the length of the crack has to be large enough to achieve a stable experiment. This is also the case for other Mode II specimens. A condition for stability is derived leading to an easily evaluated equation. Moreover, careful studies of the crack tip area during Mode II experiments often reveal an expansion of the adhesive during the final phase of loading. That is, negative Mode I loading. Due to the stiffness of the adherends, this leads to a compressive transversal loading of the process zone. Experiments and simulations show that the evaluated fracture energy depends on this constraint. A more detailed analysis of Mode II loading considering large-scale process zones gives some insight into the problem. It is also clear that Mode II has to be more carefully defined than is necessary for Mode I. Due to the transversal expansion of the process zone associated with shear, we may choose to define Mode II as a state of pure shear deformation or a state of pure shear stress. In experiments, none of these states are easily achieved. Moreover, transversally loaded short specimens can result in a process zone extending under the loading point. The result is compression of the process zone and exaggerated evaluated fracture energy. This problem is especially important to consider when evaluating soft and tough adhesives. If better understood and modelled, these effects might also be used in design so that an adhesive joint is loaded in a more favourable way.

  • 409.
    Stigh, Ulf
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Walander, Tomas
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Shear strength of adhesive layers – models and experiments2014In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 129, p. 67-76Article in journal (Refereed)
    Abstract [en]

    The mode II properties of adhesives joints are of special interest since these joints are strongest if loaded in shear. Today no standardized method is available to measure shear properties. After a brief discussion of different models used to analyse adhesive joints, we identify some of the reasons for problems that arise in some of the more frequently used experimental methods. It is shown that transversally loaded specimens with elastically deforming adherends can lead to unstable crack growth provided the un-cracked specimen is flexible. With tough adhesives, a substantial process zone develops at the crack tip. That is, most specimens are in a state of large scale yielding. If not properly taken into account, the evaluated properties will be in error. Moreover, the process zone may grow in under the loading point which hinders its evolution and yield errors in the evaluated properties. Modest variations in loading conditions using the same specimen can yield considerable variation in the evaluated properties. However, properly designed and used, both the thick-adherend lap-shear joint and the end-notched flexure specimen provide useful results.

  • 410.
    Stigh, Ulf
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Svensson, Daniel
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    On cohesive laws for delamination of composites2010In: 14th European conference on Composite materials, Budapest: University of Technology and Economics , 2010, p. 1-10, article id 159-ECCM14Conference paper (Refereed)
    Abstract [en]

    Analysis of delamination of carbon fibre reinforced composite using cohesive models is studied. A method to measure the cohesive law associated with delamination is presented. The method allows for identification of a cohesive law fit to model the fracture process at the crack tip, i.e. not considering fibre bridging. Due to the small size of the cohesive zone, an elaborated method involving simulations of the fracture process is developed. The results show larger scatter in the parameters of the cohesive law than in the fracture energy.

  • 411.
    Sukia Garmendia, Alex
    et al.
    University of Skövde, School of Technology and Society.
    Echaniz Granado, Iñigo
    University of Skövde, School of Technology and Society.
    Design, Verification and Manufacturing of a New Binding System for Crampons2013Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Crampons are a device composed of a framework containing prongs, a front-part binding and a rear-part binding system that are attached to the boots in order to climb through steep walls covered by ice, snow or rocks. Currently, the process to attach the binding system is complicated and time consuming. A new design of the rear-part binding system of the step-in crampon adapted to the current boot is therefore desired to create. The Five-Step Method is implemented to obtain the concept design. The refinement of the concept is then performed and the mechanism is designed based on the action of a spring. This improvement provides a simpler and faster attachment process to the boot and it does not require removing the gloves. The steps for the new fastening and unfastening process are lowered compared to the step-in crampon. The Value Engineering Method is used when establishing the materials and manufacturing process of the components. Chromoly steel AISI 4130 is determined for the most critical components suffering highest stresses. High Density Polyethylene polymer is used for the parts with the lowest demands concerning the stresses they have to bear. These materials stand extremely low temperatures and provide low density and high tensile strength. Commercial elements are used when possible to reduce the costs and simplify the design and assembly process. A CNC milling machine is used to manufacture the steel pieces with simple shape. The moulding process for steels is established for the steel components with more complicated shapes. Injection moulding is determined to produce the polymer parts. A simple and effective process is established for the assembly of the elements, which does not required high ability or specific tools. The design of the assembly provides the opportunity to recycle the materials. The functionality of the attachment mechanism is proved. It is verified that the critical components withstand the stresses created at them according to a security factor of 4. This is concluded accomplishing an analytical analysis and also using the Finite Element Method. The cost of the new product is estimated to be more expensive than the reference step-in crampon. The designed product weights almost the same than the current step-in crampon and it has reduced dimensions for storing it. It includes a security system that avoids the binding system being released even if a high force is applied to the system. It is important to regulate the binding system to the height of the rear-part groove of the boot and to fasten the security system tightly to avoid any clearances between the boot and the crampon. 

  • 412.
    Sumic, Aldin
    et al.
    University of Skövde, School of Engineering Science.
    Slaattelia Larsson, Andrea
    University of Skövde, School of Engineering Science.
    UTVECKLING AV RÄDDNINGSUTRUSTNING FÖR SPINALSKADADE PATIENTER2014Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During the spring of 2014, Aldin Sumic and Andrea Slaattelia Larsson, two product design engineer students at University of Skövde carried out a product development project in cooperation with the company AB Germa. The aim of the project was to develop solutions to a conceptual "vacuum-scoop" by using Germas existing vacuum technology that is used to immobilize a patient with suspected spinal injury and integrate it into the existing scoop stretcher with its function to "scoop" a patient from the accident site. The aim of the project was also to reduce the number of patient transfers and to improve safety and quality in the rescue. One of Germas strategies, to compete on the market, is to launch two new products annually. Therefore, it was more desirable that, during the mission, bring out many ideas, gladly innovative ones, than get a fully functional solution in the end. The mission was carried out according to the product development methodology set based concurrent engineering to achieve this. Working with the methodology resulted that solutions were investigated and developed in parallel and were eliminated gradually if they, for some reason established deficiencies. The mission begins with a preliminary study and empirical data gathering, which included literature review, interviews and site visits to gain deeper knowledge of the subject. Using this, the functional analyzes and the standard EN-1865 the work was detailed and a set of requirements were made. Then an idea generation session started using various creative methods and complement. The drafts from the idea generation were of different character and quality. A selection session was used on a variety of ideas for distinguishing concepts which resulted in that the concept was excluded, grouped in terms of similarity or combine. Finally, there remained three working concept. The authors chose ignore the product development methodology to develop and detail design one of the three concepts for the final presentation - the concept that became known as the vacuumskop (vakuum scoop).

  • 413.
    Svantesson, Fredrik
    et al.
    University of Skövde, School of Engineering Science.
    Grönborg, Jimmy
    University of Skövde, School of Engineering Science.
    Analysera miljöpåverkan ur ett processperspektiv med DES och LCA2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Volvo Powertrain in Skövde manufactures engines and engine components for the Volvo Group's global factories. The foundry is one of the production facilities in Skövde and is the largest foundry in Northern Europe. Over 100 000 castings are produced every year in the form of cylinder blocks, cylinder heads and flywheels. In the foundry and especially the smelter, environmental impacts are becoming significant due to its large energy demand. In the long term, the foundry needs to improve production processes from to minimize its environmental impact. The purpose of the thesis work is to identify focus areas and parameters that contribute to potential environmental impacts with the combination of DES and LCA. An analysing methodology was developed based on a process-oriented perspective. Based on relevant methods, theoretical reference framework and literature study, the project was developed. The thesis work continued by building a conceptual model for data collection. Based on the conceptual model and collected data, the simulation model is developed on an integrated Excel file for easy interface of the input data. The main purpose of the simulation model is to estimate the environmental impacts in terms of global warming, acidification and eutrophication. Two data processes are performed in the simulation model. Firstly, the input data from the conceptual model is compiled into a quantified inventory analysis. Secondly, the quantified inventory results are further categorized into potential environmental impacts, thereafter the results of the assessed environmental impacts are compiled and export to Excel file. The analysis results are presented over identified parameters with regards to the defined functional unit. The results indicate that the usage of coke is the major contributor to potential environmental impact. Therefore, efforts and further analyses should be focus on the usage of coke and identifying alternative solutions. In addition to the environmental impact assessment, a comparative analysis was conducted on a historical and alternative production scenario.  The analysis shows that the alternative production scenario utilizes 28% less electricity compared to the historical scenario.

  • 414.
    Svenman, Edvard
    et al.
    GKN Aerospace Engine Systems, Trollhättan, Sweden / Engineering Science, University West, Trollhättan, Sweden.
    Christiansson, Anna -Karin
    Engineering Science, University West, Trollhättan, Sweden.
    Runnemalm, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Engineering Science, University West, Trollhättan, Sweden .
    Experimental validation of an inductive probe for narrow gap measurement based on numerical modelling2019In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 146, p. 396-402Article in journal (Refereed)
    Abstract [en]

    Experimental validation of numeric results for an inductive probe shows that narrow gaps between two plates can be measured with accuracy suitable for laser beam welding. A two-coil inductive probe for measurement of the gap was built based on finite element modelling results. The individual coils were calibrated using a complex response method, and results from the physical coils closely match the numerical results regarding distance to gap and lift-off above the plate. The measurement of a realistic gap shows results that can be used in industrial applications for position, plate height and height alignment. 

  • 415.
    Svensson, Carl-Johan
    et al.
    University of Skövde, School of Technology and Society.
    Åkerstedt, Jesper
    University of Skövde, School of Technology and Society.
    Prognosprocessen: En fallstudie hos Asko Cylinda AB2007Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Balansering av tillgång och efterfrågan har alltid varit ett aktuellt ämne och för att klara av denna balansering krävs information om kommande efterfrågan. Denna information måste ligga så långt fram i tiden som det tar för att med säkerhet få hem exempelvis material. För att lyckas med detta använder sig företag i olika utsträckning av uppskattad framtida efterfrågan, så kallade prognoser. Prognoser kan definieras som systematiska metoder för att förutsäga framtida händelser.

    Problemet är att oavsett hur prognoser görs stämmer det prognostiserade värdet nästan aldrig överens med det verkliga utfallet. Många företag vet att deras prognoser inte är exakta utan att veta vad de ska göra åt saken. Många gånger ignorerar de bara problemet och hoppas att det ska lösa sig självt. För att kunna förbättra sina prognoser bör därför dokumentation och uppföljning ske av det arbete som görs. Med hjälp av uppföljning kan prognosfel beräknas, ett prognosfel är avvikelsen mellan det prognostiserade värdet och det verkliga utfallet. I de fall då prognosfelen är små kan företag genom dokumentation identifiera vad som urskilde dessa perioder från de med högre prognosfel.

    Författarna har i denna uppsats försökt beskriva hur företag kan uppnå en förbättrad prognosprocess med en lägre prognosavvikelse. Uppsatsen syftar också till att väcka intresset för samarbete över företagsgränser. Collaborative forecasting är en av metoderna som författarna har använt sig av för att överkomma problemen med traditionell prognostisering och som samtidigt är i linje med supply chain management. Denna metod samlar ihop och sammanställer information från både interna och externa källor för att sedan sammanställa en prognos som stöds av hela organisationen.

    Uppsatsen är en fallstudie hos vitvaruföretaget Asko Cylinda AB. För att få ytterligare idéer om hur prognosprocessen kan se ut i praktiken har författarna också tittat på prognosprocessen hos Volvo Penta AB. Båda företagens prognosprocesser har sedan analyserats och jämförts med hjälp av teori från litteratur och artiklar. Genom denna analys har författarna kommit fram till förslag på arbetssätt som Asko Cylinda AB och företag med liknande företagsmiljö kan använda sig av för att förbättra sin prognosprocess.

    Analyskapitlet är uppbyggt enligt tre scenarier, en nulägesbeskrivning, ett förslag på en enkel prognosprocess och ett förslag på en mer avancerad prognosprocess. I analysen har olika mätetal används för att åskådliggöra hur prognosavvikelsen varierar då till exempel olika prognosberäkningsmetoder används.

    Utifrån scenarierna som analyserats har författarna kommit fram till att det finns många fördelar med Asko Cylinda AB:s nuvarande arbetssätt och att flera av dessa stöds av teorin. En fördel med en enklare prognosprocess är att den allokerar betydligt mindre resurser än vad som görs i dagsläget. Detta är enligt författarna inte tillräckligt skäl att använda sig av den enkla varianten då framtiden går mot mer samarbete över företagsgränserna för att gemensamt öka konkurrenskraften. Arbetssättet som analyseras i scenario 3 ses av författarna som det bästa alternativet. Detta scenario har hämtat mycket inspiration från teorierna om collaborative forecasting, vilket bidrar till en process som arbetar mer enligt supply chain management. Även delar från både den nuvarande prognosprocessen och Volvo Penta AB:s prognosprocess har använts för att för att uppnå detta arbetssättsförslag som baserats på både teori och praktik och utformats för att vara slagkraftigt i framtiden.

  • 416.
    Svensson, Daniel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Chalmers Tekniska Högskola.
    On Cohesive Modelling ofCarbon/Epoxy Composites: Delamination and Fibre Compressive Failure2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Carbon Fibre Reinforced Polymers are widely used in engineering applications where weight saving and high mechanical performance are a key factors. However, an inheren tweakness of laminated CFRP:s is there relatively low resistance to delamination. Therst part of this thesis is devoted to extract cohesive laws associated with delamination.The method is based on fracture mechanical tests and measurement of the displacementeld close to the crack tip. The second part of the thesis is concerned with mixed modecohesive modelling under small scale yielding conditions. Under such loading conditions,a robust cohesive model should conform to Linear Elastic Fracture Mechanics (LEFM). Itis shown that two design rules for mixed mode cohesive laws are sucient to achieve thisproperty. The third part focuses a failure mode entirely dierent from delamination. Theobjective is to determine cohesive laws associated with longitudinal compressive failure.Equilibrium of congurational forces is used for this purpose. Identied congurationalforces are continuously measured by monitoring the displacements eld on the specimen'slateral surface. This allows for identication of the cohesive law.

  • 417.
    Svensson, Daniel
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Alfredsson, K. Svante
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Biel, Anders
    University of Skövde, School of Engineering Science.
    Stigh, Ulf
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Measurement of cohesive laws for interlaminar failure of CFRP2014In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 100, p. 53-62Article in journal (Refereed)
  • 418.
    Svensson, Daniel
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Alfredsson, K. Svante
    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.
    On the ability of coupled mixed mode cohesive laws to conform to LEFM for cracks in homogeneous orthotropic solids2016In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 163, p. 426-448Article in journal (Refereed)
    Abstract [en]

    The ability of coupled cohesive laws to conform to the predictions of linear elastic fracturemechanics (LEFM) in the case of small-scale-yielding (SSY) is explored. The study is concerned with cracks in homogeneous orthotropic solids and the results apply also for the case of isotropy. Both potential based and non-potential based cohesive laws are considered. It is shown that the initial stiffnesses of the cohesive law must be matched to the elastic moduli of the orthotropic solid in order to achieve a constant ratio of the cohesive stress components ahead of the crack tip. A simple condition for this is provided. For non potential based laws an additional apparently sufficient condition on the non-linear part of the cohesive law is identified: The traction vector must not change direction if the directionof the separation vector is constant. Fulfillment of this condition provides a uniform local mode mix in the cohesive zone with a value equal to the global mode mix. It is demonstrated that potential based cohesive laws display a varying local mode mix at the crack tip for cases with a mode dependent work of separation. This is identified as acomplicating feature in terms of calibrating the parameters of a cohesive law to experimental data.

  • 419.
    Svensson, Daniel
    et al.
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Alfredsson, K. Svante
    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.
    Jansson, N. E.
    GKN Aerospace Engine Systems Sweden, Trollhättan, Sweden.
    An experimental method to determine the critical energy release rate associated with longitudinal compressive failure in CFRP2013In: Proceeding of the 19th international conference on composite materials (ICCM 19), 2013Conference paper (Refereed)
    Abstract [en]

    A test specimen for measurement of the critical energy release rate associated with longitudinal compressive failure is proposed. High strains are localized by decreasing the out-of-plane thickness towards the anticipated damage region which consists of a unidirectional (UD) laminate. Thus, the compressive fibre failure mode is isolated. Microscopic studies show that the UD-material fails in a kinking mode. A method based on a generalized form of the J-integral and full-field measurements of the strain field is developed to extract the fracture energy. The fracture energy in four experiments is measured to be 20-40 kN/m. Finite element simulations  are  performed  to  validate  the experimental results. The essential features of the response are captured by modelling the damage region with cohesive elements.

  • 420.
    Svensson, Daniel
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Alfredsson, K. Svante
    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.
    Jansson, Nicklas E.
    GKN Aerospace Engine Systems, Trollhättan, Sweden.
    Measurement of cohesive law for kink-band formation in unidirectional composite2016In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 151, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Kink-band formation is an important mechanism limiting the compressive strength of high strength composites. A cohesive zone model is used to model the material in a unidirectional carbon fibre composite that forms the kink-band. Equilibrium of configurational forces is used to design and evaluate the experiments. Microscopic studies show that a kink-band is formed with the height of about 200 μm. The corresponding cohesive law has a peak stress of about 1.5 GPa, a compression at failure of about 50 μm and a fracture energy of about 25 kJ/m2.

  • 421.
    Svensson, Daniel
    et al.
    University of Skövde, School of Technology and Society.
    Walander, Tomas
    University of Skövde, School of Technology and Society.
    Evaluation of an Interphase Element using Explicit Finite Element Analysis2008Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    A research group at University of Skövde has developed an interphase element for implementation in the commercial FE-software Abaqus. The element is using the Tvergaard & Hutchinson cohesive law and is implemented in Abaqus Explicit version 6.7 using the VUEL subroutine. This bachelor degree project is referring to evaluate the interphase element and also highlight problems with the element.

    The behavior of the interphase element is evaluated in mode I using Double Cantilever Beam (DCB)-specimens and in mode II using End Notch Flexure (ENF)-specimens. The results from the simulations are compared and validated to an analytical solution.

    FE-simulations performed with the interphase element show very good agreement with theory when using DCB- or ENF-specimens. The only exception is when an ENF-specimen has distorted elements.

    When using explicit finite element software the critical time step is of great importance for the results of the analyses. If a too long time step is used, the simulation will fail to complete or complete with errors. A feasible equation for predicting the critical time step for the interphase element has been developed by the research group and the reliability of this equation is evaluated.

    The result from simulations shows an excellent agreement with the equation when the interphase element governs the critical time step. However when the adherends governs the critical time step the equation gives a time step that is too large. A modification of this equation is suggested.

  • 422.
    Svensson, Erik
    et al.
    University of Skövde, School of Technology and Society.
    Viitala, Tero
    University of Skövde, School of Technology and Society.
    FEM- analys av standardräls BJV50: Undersökning av belastningsfall vid vägning av malmvagn UID II2007Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    When goods wagons are weighed out with a strain gage assembled to a rail there are certain factors that affect the results of the measurement. This report investigates by computer based simulations how the foundation and the speed of a wagon affect the strain and the deformation of a rail. Furthermore, in the report investigations are made how disturbances in the form of changes in temperature and changes of the contact force between the wheel of a wagon and the rail affect strain. The changes can occur due to non-round wheels, vibrations of a wagon or irregular rail.

  • 423.
    Svensson, Erik
    et al.
    University of Skövde, School of Engineering Science.
    Wiechert, Marcus
    University of Skövde, School of Engineering Science.
    Abrasiv nötning av polymerer tillverkade genom 3D-skrivning2015Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Volvo Cars in Skövde manufacture and assemble Volvo engines. When attaching the ignition coil to all 4-cylinder engines, a special mounting tool is required. This mounting tool is currently manufactured from injection-molded polyoxymethylene (POM), a thermoplastic. It has been noted that the life span of the tool is shortened as a result of abrasive wear that occurs during the attachment process of the ignition coil.

    An investigation of the possibility of manufacturing the mounting tool with a 3D-printer is undertaken in cooperation with ÅF, a consultant to Volvo Cars. A literature study is first presented to introduce broader knowledge on the subject. The abrasive wear and other material characteristics such as tensile strength, compressive strength and elongation of  POM and an alternative material for 3D-printing,  Ultem™, an amorphous thermoplastic polyetherimide are discussed.  These material characteristics are studied further and considered in tandem with both a theoretical analysis and a wear experiment, based on the pin-on-disc method.

    It is shown in the theoretical analysis that the wear is approximately six times larger for Ultem™ when compared to POM. The wear resistance of Ultem™ is highest when wear occurs parallel to the direction of the printed layers. In contrast, the experiment shows that the wear is about three times larger in Ultem™ than in POM.  The highest tensile strength of Ultem™ is also found in the direction of the printed layers. Some issues with the small elongation of the 3D-printed material are presented.

    It is recommended that ÅF apply the 3D-printing technique with Ultem™ only for construction details with complex geometries and where the material elongation will not exceed 5%. It is also recommended that ÅF both support and contribute to this innovative technique in order to develop leading edge competence in the subject.

  • 424.
    Svensson, Patrik
    et al.
    University of Skövde, School of Technology and Society.
    Klippberg, Lovisa
    University of Skövde, School of Technology and Society.
    Jansson, Björn
    University of Skövde, School of Technology and Society.
    Den nya generationen KinBag: The new generation of KinBag2007Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    This report summarizes a Bachelor Degree Project in Integrated Product Development,carried out during the spring semester in 2007 by three students at the Product Design Engineering programme at the University of Skövde. The project was performed as an assignment for KinBag ab, a sister subsidiary to Kinnegrip ab in Lidköping, who develop,manufacture and market the golf bag KinBag, a bag with an integrated wheel carriage system. The purpose of the project was to redesign the golf bag to attract a target group consisting of golfers aged between 20 and 40.

    The layout of the project was as follows: The project began with a feasibility study where different problems were identified with the basis of a market research which eventually was summarized in a dynamic specification of requirements. The feasibility study was followed by a generation of ideas which contained everything from sketches to simple mock-ups with an intensive amount of thoughtful brainwork and information gathering in between. This led

    to the development of a number of design concepts, both on an overall level and on different parts of the golf bag. Even more detailed models were created and visualized in a three dimensional environment by means of a CAD program.

    The report portrays the product design process and methods utilized in the project, as well as the final result - a full-scale operational prototype of the new generation of KinBag.

  • 425.
    Svensson, Victor
    et al.
    University of Skövde, School of Engineering Science.
    Martinsson, Philip
    University of Skövde, School of Engineering Science.
    Människa-robot samarbete med hjälp av virtuell simulering2019Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The introduction of industry 4.0 initiated the vision of a smart factory with all the supplied characteristics of highly individualized processes connecting the real world with virtual reality. Collaboration between humans and machines has been desirable for a long time but the associated risks have been a restriction. The interaction between collaborative processes and virtual reality offers the possibility where new concepts and ideas can be developed in a safe and sustainable environment. The capability to reconstruct, evaluate and test new concepts and ideas without affecting the real world is desirable relative to the newly introduced awareness in sustainability. The purpose of this project is to investigate the possibilities regarding in what extent virtual reality can contribute when training operators, identifying possible improvements, identifying risks associated with ergonomics and assisting the simulation development. The projects associated company is located in Skövde and is regarded one of the leading companies within the vehicle manufacturing industry. The overall aim of the project is to develop a simulation environment using human-robot collaboration capable of interaction through virtual reality. Several limitations have been engaged in order to narrow the project scope down to a reasonable level. These limitations involve exclusively using Siemens Process Simulate software, HTC Vive for equipment regarding virtual reality and usage of Universal Robots UR10e as the collaborative robot.

    In order to construct the simulation environment in a good way and achieve the project aims a suitable methodology has been developed. The procedure started with an extensive literature review and theoretical framework in order to obtain the necessary knowledge in the area. Both qualitative and quantitative research methods have been used for gathering relevant information regarding necessary equipment and manufacturing operations. A summary of the collected data and theory resulted in a specification for the simulation environment prior to the construction phase. The two final versions of the simulation environment have successfully been able to achieve the project goals of training operators, possible improvement identification and ergonomics.

  • 426.
    Syberfeldt, Anna
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Multi-Objective Optimization of a Real-World Manufacturing Process Using Cuckoo Search2014In: Cuckoo Search and Firefly Algorithm: Theory and Applications / [ed] Xin-She Yang, Springer, 2014, p. 179-193Chapter in book (Refereed)
  • 427.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Andersson, Martin
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ng, Amos
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Bengtsson, Victor
    PostNord AB, Solna, Sweden .
    Multi-Objective Evolutionary Optimization of Personnel Scheduling2015In: International Journal of Artificial Intelligence & Applications, ISSN 0976-2191, E-ISSN 0975-900X, Vol. 6, no 1, p. 41-52Article in journal (Refereed)
    Abstract [en]

    This paper presents an evolutionary multi-objective simulation-optimization system for personnelscheduling. The system is developed for the Swedish postal services and aims at finding personnelschedules that minimizes both total man hours and the administrative burden of the person responsible forhandling schedules. For the optimization, the multi-objective evolutionary algorithm NSGA-II isimplemented. In order to make the optimization fast enough, a two-level parallelisation model is beingadopted. The simulation-optimization system is evaluated on a real-world test case and results from theevaluation shows that the algorithm is successful in optimizing the problem.

  • 428.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Ayani, Mikel
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    A holistic solution for integrating a simulated twin of an automation system during the system’s entire life-cycle2018In: Advances in Manufacturing Technology XXXII: Proceedings of the 16th International Conference on Manufacturing Research, incorporating the 33rd National Conference on Manufacturing Research, September 11–13, 2018, University of Skövde, Sweden / [ed] Peter Thorvald, Keith Case, Amsterdam: IOS Press, 2018, p. 405-410Conference paper (Refereed)
    Abstract [en]

    This paper describes a project that attempts to develop a holistic solution for integrating a simulated twin of an automation system during the system’s entire life-cycle. With such holistic solution, virtual commission could be undertaken in all steps of the life-cycle which facilitates companies in realizing flexible and intelligent automation systems. Based on the simulated twin, the companies could easily and cost-efficiently evaluate modifications, make improvements, and train operators when changes in the production setup occurs due mass-customization or new products being introduced. This aids the companies in staying competitive on a global and rapidly changing market and meet the challenges coming with the forth industrial revolution, such as mass-customization and short product life-cycles.

  • 429.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Danielsson, Oscar
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Holm, Magnus
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Wang, Lihui
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Royal Institute of Technology, Stockholm, Sweden.
    Dynamic operator instructions based on augmented reality and rule-based expert systems2016In: Research and Innovation in Manufacturing: Key Enabling Technologies for the Factories of the Future - Proceedings of the 48th CIRP Conference on Manufacturing Systems / [ed] Roberto Teti, Elsevier, 2016, Vol. 41, p. 346-351Conference paper (Refereed)
    Abstract [en]

    Augmented reality is currently a hot research topic within manufacturing and a great potential of the technique is seen. In this study, we aim to increase the knowledge of the adaptation and usability of augmented reality for the training of operators. We propose an approach of using dynamic information content that is automatically adjusted to the individual operator and his/her learning progress for increased efficiency and shorter learning times. The approach make use of the concept of expert systems from the field of artificial intelligence for determine the information content on-line. We develop a framework called "Augmented Reality Expert System" (ARES) that combines AR and expert systems. A proof-of-concept evaluation of the framework is presented in the paper and possible future extensions are discussed.

  • 430.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Gustavsson, Patrik
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Increased Robustness of Product Sequencing using Multi-Objective Optimization2014In: Proceeding of 47th CIRP Conference on Manufacturing Systems, Elsevier, 2014, Vol. 17, p. 434-439Conference paper (Refereed)
    Abstract [en]

    Almost all manufacturing processes are subject to uncontrollable variations, caused, for example, by human operators or worn-out machines. When optimizing real-world product sequencing problems, it is of importance to find solutions that are robust, that is, whose performance remains relatively unchanged when exposed to uncertain conditions. In this paper, an extension of the traditional method of handling variations through replications is suggested that aims at finding solutions with an increased degree of robustness. The basic idea is to use standard deviation as an additional optimization objective and transform the single-objective problem into a multi-objective problem. Using standard deviation as an additional objective aims to focus the optimization on solutions that exhibit both high performance and high robustness (that is, having low standard deviation). In order to optimize the two objectives simultaneously, a multi-objective evolutionary algorithm is utilized. The proposed method for improved robustness is evaluated using a real-world test case found at the company GKN Aerospace in Sweden. GKN Aerospace manufactures a variety of different components for aircraft engines and aero derivative gas turbines. The company has recently installed a new workshop, and the focus of the study is on the x-ray stations in this workshop. For performing optimizations the company has created a simulation model that realistically mimics the workshop. As an optimization technique, a multi-objective evolutionary algorithm called NSGA-2 is being used. The algorithm considers the mean value and standard deviation from replications of the stochastic simulation as objectives, optimizing both of them simultaneously. Results from the study show that the optimization is able to successfully find robust solutions using the proposed method. However, the general increase in algorithm performance expected with the proposed method is absent, and possible reasons for this are discussed in the paper.

  • 431.
    Syberfeldt, Anna
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Gustavsson, Patrik
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Svantesson, Joakim
    GKN Aerospace.
    Almgren, Torgny
    GKN Aerospace.
    A Case Study of Evolutionary Simulation Based Optimization in Aircraft Engine Manufacturing2014In: Industrial Simulation Conference, Skövde, June 11-13, 2014, 2014, p. 91-96Conference paper (Refereed)
  • 432. Szekely, Bulcsu
    et al.
    Saranen, Juha
    Hilmola, Olli-Pekka
    Hilletofth, Per
    University of Skövde, School of Technology and Society.
    Globalization and International Division of Work: New Ways of Co-operation within Lean Production Networks – Evidence from Russia, Finland & Sweden2008In: Fourth International Railway Logistics Seminar: Co-operation among Transportation Modes in Northern Europe, Lappeenranta University of Technology , 2008, p. 181-198Conference paper (Other academic)
  • 433.
    Tan, Anita
    et al.
    University of Skövde, School of Engineering Science.
    Edenfeldt, Isabelle
    University of Skövde, School of Engineering Science.
    Studie av Crowdsourcing som metodik inom produktutveckling av träningshandskar2016Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis has been carried out at the University of Skövde in collaboration with Casall Sports AB. The project goal was to evaluate and implement the method Crowdsourcing in Casall’s current product development process. The founder of the term Crowdsourcing, Jeff Howe, believed in engaging the public to solve different ranges of problems within a company. To explore the possible use of the method, a product development process was created for the company to work after when using Crowdsourcing.  This process was an outcome from literature studies in product development processes and in Crowdsourcing methods. With the use of this developed process, implementation of Crowdsourcing to Casall’s product development process was made. The result is presented as a guide for Casall using Crowdsourcing when developing new products or product lines. The online-platform crowdSPRING.com was chosen for applying phases including Crowdsourcing. To evaluate the guide, a mission statement for the development of training gloves was created for evaluation with a focus group of 10 people. The outcome of this project is a product development process with implementation of the method Crowdsourcing presented as a guide and accordingly a new approach for Casall when using crowdSPRING.

  • 434.
    Thannan, Andreas
    et al.
    University of Skövde, School of Technology and Society.
    Göransson, Andreas
    University of Skövde, School of Technology and Society.
    Utformining av vindavledare för flakkåpa2012Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to future EU-regulations, car manufacturers need to reduce their carbon dioxide emissions in order to compete with other companies. This report discusses the development of a wind deflector for Auto-kaross i Floby AB´s Ekobox mounted on a Volkswagen Transporter. The goal is to, due to future regulations of a maximum of 175 CO2/km for lightweight transport vehicles, reduce fuel costs and carbon diox-ide emissions by reducing air resistance. A study of aerodynamics and today’s market was made to find solutions applied to similar prob-lems. Through a costumer survey made by Autokaross, customer needs could be identified which formed the product specification. To gather a big amount of ideas during the concept generation several brainstorming methods were applied in sessions. The ideas were de-veloped into concepts and through consultations from the supervisor at Autokaross the most interesting concepts were picked out. The most important part in the project was the analysis in CFD, Computational Fluid Dynamics, where different cross sections were tested as well as full 3D-models to see what forms performs best and gets the lowest air resistance. When the final concept was to be chosen a concept selec-tion matrix was made were the results from the CFD-simulations had the biggest impact. The final result consists of two parts, a roof spoiler and a boattail, together with Autokaross existing side skirt which ful-fills the goal to reduce the air resistance and thus the carbon dioxide emission and the fuel costs. With these three parts the air resistance is reduced by 27 percent.

  • 435.
    Thorvald, Peter
    University of Skövde, School of Technology and Society. University of Skövde, The Virtual Systems Research Centre.
    Presenting Information in Manual Assembly2011Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Ever since industrialization, manufacturing companies have competed with each other in trying to make the best and the cheapest product and the automotive industry is definitely no exception. The ‘arms race’ between truck and car manufacturers has pushed manufacturing technology and production practice to where it is today. However, whereas companies have traditionally competed with the engineering excellence and technology of their products, the human effort in production is often neglected. After all, there are still many tasks that require the flexibility and intelligence of a human worker.

    This thesis focuses entirely on the information context of assembly workers. It investigates and discusses their general information behaviour in terms of information need, syntax of information, information sources and technology as well as basic cognitive abilities used to utilize information such as attention and memory. The thesis presents relevant literature on the subject of information behaviour and pinpoints potential hazards of information design in manual assembly. It also identifies three hypotheses that suggest improved productivity and quality of work as a result of certain changes in the information landscape. One hypothesis deals with the layout of information, a second deals with the syntax used to identify parts and a third deals with the information medium used to convey information.

    Analysis of empirical data gathered shows, among other things, that using unstructured and batched information favours productivity of work; using a syntax with semantic content as opposed to traditional article numbers without any semantic content also improves productivity of work; and using a mobile information unit betters the quality of work.

    The purpose of the thesis is to present the beginnings of a road map towards the greater understanding of information presentation in manual assembly. As previous research on this application area has been scarce, it draws upon existing theories found in other sciences, primarily cognitive science and its applications such as Human-Computer Interaction (HCI), information theory and human error.

    􀀁

  • 436.
    Thorvald, Peter
    et al.
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Bäckstrand, Gunnar
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Högberg, Dan
    University of Skövde, The Virtual Systems Research Centre. University of Skövde, School of Technology and Society.
    Case, Keith
    Loughborough University, Loughborough, UK.
    Syntax and Sequencing of Assembly Instructions2012In: Advances in Usability Evaluation: Part II / [ed] Francesco Rebelo & Marcelo M. Soares, CRC Press, 2012, p. 266-275Chapter in book (Refereed)
    Abstract [en]

    Minimalism of design is a concept often found in Human-computer interaction (HCI). It is a concept that emphasizes the presentation of as little information as possible to reduce the perceptual strain and visual search of the subject. However, in a manufacturing context, such as in manual assembly, state of the art information presentation is rarely minimalistic. Rather, organizations tend to push out as much information as possible without necessarily concerning themselves with how this information is presented to, or perceived by, the worker. This leads to a situation that is far from ideal from an HCI perspective, likely to reduce human performance and wellbeing, in turn negatively affecting overall production system performance. Obviously, there are several potential ways of addressing this issue. Perhaps the most evident way is to simply reduce the amount of information that is presented and only present the essentials. This paper will investigate and discuss how information presentation can be minimized without reducing the information content through information syntax and layout.

  • 437.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Case, KeithUniversity of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Loughborough University.
    Advances in Manufacturing Technology XXXII: Proceedings of the 16th International Conference on Manufacturing Research, Incorporating the 33rd National Conference on Manufacturing Research, September 11-13, 2018, University of Skövde, Sweden2018Conference proceedings (editor) (Refereed)
  • 438.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Distributed cognition at work - A systemic perspective on human based manufacturing2015In: Proceedings of ICMR 2015 / [ed] Linda Newnes, Aydin Nassehi & Vimal Dhokia, Bath, UK: University of Bath , 2015, p. 195-200Conference paper (Refereed)
    Abstract [en]

    Cognitive science is becoming increasingly central within human factors & ergonomics and, since at the same time, there has long been a call for a more systemic perspective in the area with a somewhat wider unit of analysis, this paper argues that the theoretical framework of distributed cognition would greatly benefit the area. It would offer a more complete understanding of the user within a greater context, be it social, cultural or materialistic. This paper aims to characterize and analyse the domain of manufacturing as a complex socio-technical system from a distributed cognition perspective; focusing on the use, mediation and integration of different forms of representations, tools and artefacts in this domain.  The paper further proposes and exemplifies benefits of using a distributed cognition framework in the manufacturing domain as studied by human factors and ergonomics.

  • 439.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Virtual Systems Research Centre.
    Andreasson, Rebecca
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre. Uppsala Universitet.
    CLAM – A method for cognitive load assessment in manufacturing2017In: Advances in Manufacturing Technology XXXI / [ed] Gao, J., El Souri, M., Keates, S., Amsterdam: IOS Press, 2017, Vol. 6, p. 114-119Conference paper (Refereed)
    Abstract [en]

    The increasing complexity and demands of assembly operations in manufacturing has been shown to lead to increased cognitive load in assembly workers. Previous work has outlined the complexity of an assembly worker’s situation both in terms of difficulty and speed of work and there have been a few attempts at creating frameworks and methods for understanding the key aspects of what creates increased cognitive load. This paper presents a tool for assessing cognitive load in manufacturing, primarily assembly. The paper presents the method and an accompanying tool as well as some insights derived from this method development. The intended contribution of the work is to make a difference in reducing the cognitive load of assembly workers on the shop floor, thus focusing the development on applicability and usability of the tool in practice. 

  • 440.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Andreasson, Rebecca
    Uppsala University, Department of Information Technology, Uppsala, Sweden.
    On the development of a method for cognitive load assessment in manufacturing2019In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 59, p. 252-266Article in journal (Refereed)
    Abstract [en]

    The increasing complexity and demands of assembly operations in manufacturing has been shown to lead to increased cognitive load in assembly workers. Previous work has outlined the complexity of an assembly worker's situation both in terms of difficulty and speed of work and there have been a few attempts at creating frameworks and methods for understanding the key aspects of what creates increased cognitive load. This paper presents the development of an analytic method, denoted CLAM (Cognitive Load Assessment for Manufacturing), and a tool for assessing cognitive load in manufacturing, primarily assembly. It outlines the journey of the development as well as discusses and problematizes relevant meta-methodological issues paired with method development. The intended contribution of the work is to make a difference in reducing the cognitive load of assembly workers on the shop floor, thus focusing the development on applicability and usability of the tool in practice. With this purpose in mind, focus of the method development has been on the practitioners, i.e. the method should not require any expert knowledge to be applied. The CLAM method and accompanying documentation such as a handbook containing instructions towards using the method and interpreting the results, is available in an online tool.

  • 441.
    Thorvald, Peter
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Chalmers University of Technology, Gothenburg, Sweden.
    Lindblom, Jessica
    University of Skövde, School of Informatics. University of Skövde, The Informatics Research Centre.
    Kolbeinsson, Ari
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Embodied Interactions in Cognitive Manufacturing2020In: Advances in Neuroergonomics and Cognitive Engineering: Proceedings of the AHFE 2019 International Conference on Neuroergonomics and Cognitive Engineering, and the AHFE International Conference on Industrial Cognitive Ergonomics and Engineering Psychology, July 24-28, 2019, Washington D.C., USA / [ed] Hasan Ayaz, Springer, 2020, p. 419-426Conference paper (Refereed)
    Abstract [en]

    This paper presents a discussion on the role of embodied interaction with a basis in social embodiment effects and how they can be viewed in light of manufacturing ergonomics. The social embodiment effects are four statements, grounded in empirical findings, which highlight the interplay of social stimuli, embodied responses, and cognitive processing. They suggest and base an argument for how embodiment is central to cognitive processing, how bodily states interact extensively with cognitive states, and ultimately how embodied interaction is ubiquitous in human cognition. The paper further presents a view on how human based manufacturing can be studied in light of this argument, exploring other areas where social embodiment has been further researched, with an aim to suggest examples of where social embodiment effects might be found in manufacturing ergonomics and form a basis for future investigations. 

  • 442.
    Tjus, Anna
    et al.
    University of Skövde, School of Technology and Society.
    Johansson, Annie
    University of Skövde, School of Technology and Society.
    A minor field study for combined rainwater andpond harvesting system and purification technology in the village Macedonia, Amazon basin, Colombia2008Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    This study is a bachelor degree project which focuses on the lack of safe drinking water in a small village known as Macedonia in the Amazon basin in Colombia. The inhabitants of the village are 850 to the number and have never had access to safe drinking water. To solve this problem a system has been built where the rainwater is harvested in a pond and also from a church roof

    During the dry season the rainwater in the pond is harvested and pumped into sedimentation tanks. Thereafter, the water is led into the sand filtration tanks. While during the rain season, the rainwater is harvested from a church roof which is situated at highest level in Macedonia. The water is stored in a cistern and then it is led into sand filtration tanks via pipes. This means that the pond water and rainwater are never mixed before entering the filtration tanks.

    The sand filtration tanks contain about 1000 mm thick layer of sand and under it, a layer of gravel which is placed in the bottom of the tank. It takes a while for the water to be filtered through the sand filtration tank. Afterwards, it is led into the final tank, where the drinking water is stored ready to be used.

    The method of using slow sand filtration (SSF) is suitable for small scale-projects and therefore for this project a good idea for making drinking water. SSF requires no mechanical power or replaceable parts, this is why the technique is good for purifying water in developing and isolated areas.

    The result of the system is water with satisfied quality running through pipes and taps, ready to be consumed.

     

     

     

     

  • 443.
    Torosian, Rojé
    et al.
    University of Skövde, School of Technology and Society.
    Elmehag, Elin
    University of Skövde, School of Technology and Society.
    Life Cycle Assessment of an Ocean Energy Power Plant: Evaluation and Analysis of the Energy Payback Time with Comparison Between Sweden and Tanzania2013Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Energy is an essential asset in the present society. It is needed for transportation, electricity and heating. Fossil fuels, being a limited reserve, are presently the dominating resource from which energy is being used. As indus-tries and consumers around the world use more energy for each passing day it becomes vital to shed some light on how important it is to decrease the global energy demand. Fossil fuels are needed to be replaced by renewa-ble energy sources, such as solar and wind power, in order to obtain a more sustainable development.When a new product is being developed it is usually important to analyze the potential environmental impact, suggestively by conducting a life cycle analysis, prior to manufacturing. Deep Green, being a tidal energy device for generation of electricity, is a product in its initial developing stage. In this thesis a lifecycle assessment has been conducted of the complete product with the purpose of achieving an analysis of how different choices of materials affect the energy usage, CO2 footprint and the energy payback time. Identifications by comparison have been taken into account to determine which component of Deep Green that contributes mostly to the energy usage and CO2 footprint. In addition to the Life Cycle Assessment, LCA, a digital model, created in an Excel workbook, has been developed to simplify calculations of the energy usage, CO2 footprint and energy payback time. The digital model, namely ENCO©, provides the possibility to interchange choice of materials for each component in order to evaluate the potential environmental impact and the energy payback time. Deep Green consist of 34 different components which are included in the LCA but an initial analysis shows that only twelve specific parts contribute largely to the energy usage and the CO2 footprint. The foundation and the wing structure account for 78 % and 15 % respectively of the energy usage along with ten other parts which together stand for an additional 6 %. Remaining 27 parts share the final percentile. Given the materials provided by the company of Minesto the total energy usage and CO2 footprint for the complete product corresponds to approx-imately 4500 GJ and 342 tonne respectively. The foundation is the part of Deep Green that contributes most to the total environmental impact.Depending on the defined materials for each component the energy payback time varies between 220 to 260 days which is to say that a production of Deep Green would be profitable. Nevertheless the conducted LCA has several delimitations which should be reflected upon prior a final decision is made.The resulted Energy Payback time, EP, should be carefully used and presented with the system boundaries, since they affect the EP very much. The outcome of energy consumption and CO2 footprint, depend highly on the choice of end of life management. Based on the result it is recommended that the foundation is left on the sea-bed at the end of its lifecycle to obtain the best EP.An investigation of whether it is possible to position the complete supply-chain within the boundaries of a de-veloping country, namely Tanzania, has also been conducted along with the LCA. It is believed that most of the raw materials, which are necessary for the manufacturing of Deep Green, are mined in Tanzania. It is however possible to import those materials which are not available within the country. When considering Tanzania, as a point of implementation for Deep Green, the energy payback time will become higher compared to Sweden or England since more components need to be imported which in turn generates an increase of transportation.It is recommended that a new calculation of the EP and the carbon footprint are done when Deep Green is fully developed. ENCO© can advantageously be used for this. It is also recommended that the distribution cables and the installation are included.

  • 444.
    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.

  • 445.
    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.

  • 446.
    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. 

  • 447.
    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.

  • 448.
    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
  • 449.
    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.

  • 450.
    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.

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