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  • 401. Byggeth, Sophie
    et al.
    Broman, Göran
    Environmental Aspects in Product Development: an Investigation among Small and Medium Sized Enterprises2000Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Small- and Medium sized Enterprises (SMEs) represent a large part of industry. Environmental considerations during product development in SMEs therefore imply a large potential for reducing society's environmental impact. Implementing environmentally adapted product development among SMEs has been considered difficult and is uncommon. Our approach is to develop a qualitative Method for Sustainable Product Development (MSPD) that relates both to a framework for sustainability and to the ordinary product development process. The aim is to guide the user to avoid problems related to social and ecological non-sustainability without demanding extensive expertise knowledge. Two surveys in ten Swedish SMEs have been carried out. An initial survey registered their product development procedures and environmental work as well as desired characteristics of a new suggested method for integrating environmental aspects into the product development process. A second survey registered additional desired characteristics and improvement suggestions when testing an early version of our MSPD. The surveys and the structure of our MSPD are presented, and the desired characteristics for a workable method in SMEs, found in our investigation and in literature, are discussed.

  • 402.
    Byggeth, Sophie
    et al.
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Broman, Göran
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Holmberg, John
    Lundqvist, Ulrika
    Robèrt, Karl-Henrik
    A Method for Sustainable Product Development In Small and Medium Sized Enterprises2000Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A qualitative Method for Sustainable Product Development (MSPD) is presented. It consists of three tools: an Integrated Product Development Model (IPDM), a strategic planning process based on backcasting (ABCD-analysis), and a matrix containing hierarchically ordered and guiding questions. This Sustainability Product Analysis (SPA) matrix has conditions for sustainability along one axis and the life cycle of the product along the other axis. The SPA-matrix is used in the ABCD-analysis, which in turn is used in the IPDM. Integrating the tools in this way and using overall conditions for sustainability is unique compared to many other tools and methods for design for the environment. The MSPD is being developed in discussions with ten small- and medium sized enterprises.

  • 403.
    Byggeth, Sophie
    et al.
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Broman, Göran
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Lundqvist, Ulrika
    Robèrt, Karl-Henrik
    Blekinge Tekniska Högskola, Institutionen för maskinteknik.
    Holmberg, John
    An Approach to Sustainability Product Analysis in Product Development2001Konferansepaper (Fagfellevurdert)
  • 404.
    Byggeth, Sophie
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Broman, Göran
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Robèrt, Karl-Henrik
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    A method for sustainable product development based on a modular system of guiding questions2007Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 15, nr 1, s. 1-11Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a Method for Sustainable Product Development (MSPD) with the aim of integrating social and ecological aspects of sustainability with a strategic business perspective in product development. The method applies backcasting from basic principles for sustainability, which allows a strategic approach, and it includes a modular system of guiding questions that are derived by considering these principles and the product life cycle. Initial testing in Swedish companies indicates that the suggested MSPD promotes a ‘bird’s eye’ perspective and encourage and aid development of products that support society’s transformation towards sustainability. Furthermore, it is concluded that the modular system provides flexibility and user-friendliness.

  • 405.
    Byggeth, Sophie
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Hochschorner, Elisabeth
    Handling trade-offs in Ecodesign tools for Sustainable Product Development and Procurement2005Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 14, nr 15-16, s. 1420-1430Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Trade-off situations often occur in the product development and procurement processes when alternative solutions emphasize different aspects that have to be balanced against each other. Ecodesign tools can be used in both product development and purchasing, for example to prescribe design alternatives, assess environmental impacts or to compare environmental improvement alternatives. However, it is not always clear what should be chosen in trade-off situations. In this study, fifteen different Ecodesign tools were analyzed to ascertain whether a valuation is included in the tools, in what way the tools give support in different types of trade-off situations and whether the tools give support from a sustainability perspective. Nine of the fifteen tools analyzed included a valuation and were able to give support in a trade-off situation, but the support was not sufficient. The valuation should include a lifecycle perspective and a framework for sustainability. Otherwise it can lead to strategically incorrect decisions from a sustainability perspective with concomitant risks of sub-optimized investment paths and blind alleys. However, all the analyzed tools can be complemented with other tools and methods based on strategic planning towards sustainability in order to include a framework for sustainability.

  • 406.
    Byggeth, Sophie
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Ny, Henrik
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Wall, Johan
    Broman, Göran
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Robèrt, Karl-Henrik
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för maskinteknik.
    Introductory Procedure for Sustainability-Driven Design Optimization2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In response to the increasingly competitive global market, there is a growing interest in design optimization. Being able to include aspects of socio-ecological sustainability in product design should aid companies to both improve current competitiveness and to identify viable long-term investment paths and new business opportunities in the evolving sustainability-driven market. A case study of a water jet cutting machine is used to illustrate a new iterative optimization procedure that combines a technical assessment with a sustainability assessment. Sustainability assessment methods/tools are first used to identify prominent sustainability problems from present-day flows and practices (“societal indicators”) and to generate ideas of long-term solutions and visions. Based on this, preliminary ideas about likely desirable changes in machine properties are obtained. Technical investigations are then performed to assess if/how these particularly desirable changes in machine properties could in principle be realized through changes in design variables. After that, obtainable changes are fed back to a new and more refined sustainability assessment to find out the societal implications of these changes. This may in turn result in other desirable design changes, which may call for a new and more refined technical assessment, etcetera. The experience from the case study indicates that the suggested integrated and iterative working procedure should be able to add information about socio-ecological impacts of product properties and influence design criteria used in prioritisation situations during product development.

  • 407. Bylund, Nicklas
    et al.
    Eriksson, Magnus
    Simulation driven car body development using property based models2001Inngår i: Proceedings of the IBEC 2001, International Body Engineering Conference and Exhibition: October 16 - 18, 2001, Detroit, Michigan, USA ; co-located at Cobo Center with Digital Car Conference & Exhibition, Detroit: Society of Automotive Engineers, Incorporated , 2001Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A method for the development of car bodies, from conceptual to detailed design, is presented. The conceptual design is broken down to a numerical property- based model (PBM) representing the mechanical behavior of the concept. In the PBM, the local properties are balanced to fulfill the global stiffness requirements. The main topology is defined and the structural components, i.e., joints, beams and sheets are connected in predefined nodes and represented in a finite element (FE) model as super elements, beam elements and thin shell elements. In the realization of the car structure, the performance of the PBM components are used as requirements in the detailed design. Different technologies, materials and manufacturing processes can be considered as long as the properties of the component agree with the ones stated by the PBM. The detailed design of each component is made by design engineers, supported by single purpose tools. The design engineers iterate the design until only a small difference between target and component performance exists

  • 408.
    Byström, Berth-Ove
    et al.
    Luleå tekniska universitet.
    Nilsson, Anders
    Luleå tekniska universitet.
    Olsson, Erland
    Luleå tekniska universitet.
    Chain saw vibration: of hand vibration and development of mechanical hand model1978Rapport (Annet vitenskapelig)
  • 409.
    Byström, Berth-Ove
    et al.
    Luleå tekniska universitet.
    Nilsson, Anders
    Luleå tekniska universitet.
    Olsson, Erland
    Luleå tekniska universitet.
    Development of artificial hands for use in chain saw vibration measurement1982Inngår i: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 82, nr 1, s. 111-117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dynamic properties of the human hand were measured in the laboratory. The results were compared with those obtained by others and used to test three different hand model ideas. One of these was further developed and designed to fit in a test rig. Measurements were made on chain saws in the rig during cutting and with the chain running free. The results are compared to similar measurements on hand held chain saws. The hand model test results show good agreement with the hand held measurements but have much better repeatability.

  • 410.
    Bäckman, Tobias
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Ehmke, Gustav
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Utveckling av testsystem för Interface Test Adapter till Gripen ATE2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

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

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

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

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

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

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

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

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

  • 411.
    Bäckström, Mikael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Rännar, Lars-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Kuzmin, Leonid
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för teknik och hållbar utveckling.
    Influencing factors on time-loss after shooting in Biathlon2011Inngår i: Moderns systems for application in Biathlon, Omck: Russian Sports Federation , 2011, s. 154-159Konferansepaper (Fagfellevurdert)
  • 412.
    Bängtsson, Erik
    et al.
    Department of Information Technology, Uppsala University.
    Noreland, Daniel
    Department of Information Technology, Uppsala University.
    Berggren, Martin
    Department of Information Technology, Uppsala University.
    Shape optimization of an acoustic horn2003Inngår i: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 192, s. 1533-1571Artikkel i tidsskrift (Fagfellevurdert)
  • 413. Bölcs, A
    et al.
    Fransson, Torsten
    KTH, Skolan för industriell teknik och management (ITM).
    Schläfli, D
    AGARD Conference Proceedings No. 468 on "Unsteady Aerodynamic Phenomena in Turbomachines", Luxemburg, August, 1989.1989Konferansepaper (Fagfellevurdert)
  • 414. Bölcs, A
    et al.
    Fransson, Torsten
    KTH, Skolan för industriell teknik och management (ITM).
    Schläfli, D
    Time-Dependent Measurements on Vibrating Annular Turbine Cascades Under Various Steady-State Operating Conditions1989Konferansepaper (Fagfellevurdert)
  • 415.
    Bölke, Alexander
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Swahn, Lars
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Att simulera en uthållighetsidrottare2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    De två fysiologiska egenskaper som har störst betydelse för en individs uthållighet är maximalsyreupptagningsförmåga och den så kallade övre laktattröskeln. Dessa egenskaper tas bäst fram genomett så kallat tröskeltest och ett maxtest, vilket en litteraturstudie och en intervju av en expert i ämnethar visat.

    Egenskaperna skulle sedan kopplas till en Matlabmodell utvecklad för att simulera bland annatutmattning för en individ på en given bana. För att åstadkomma detta genomfördes ett tröskeltest ochett maxtest på två individer för att mäta den övre laktattröskeln och den maximalasyreupptagningsförmågan. Testerna utfördes på Aktivitus i Solna. Därefter simulerades maxtesternaför varje individ i denna Matlabmodell.

    Det visade sig att den övre laktatröskeln hade en ganska direkt koppling till Matlabmodellen vilketinnebär att man kan föra in uppmätta värden direkt i modellen medan den maximalasyreupptagningsförmågan koppling till modellen behöver undersökas närmare.

    Experimenten har genomförts som en del av ett projekt som drivs av professor Anders Eriksson påKTH och hans kollegor från Karolinska Institutet och Mittuniversitetet. Teknik/arbetsekonomi somhar betydelse för uthålligheten har i detta arbete förbisetts. För att få bättre och säkrare resultatbehöver fler tester utföras.

  • 416.
    Börvik, Tore
    et al.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Clausen, Arild H.
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Eriksson, Magnus
    Berstad, Torodd
    SINTEF Materials and Chemistry.
    Langseth, Magnus
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Experimental and numerical study on the perforation of AA6005-T6 panels2005Inngår i: International Journal of Impact Engineering, ISSN 0734-743X, E-ISSN 1879-3509, Vol. 32, nr 1-4, s. 35-64Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Extruded aluminium panels find their use in many different structures such as offshore platforms, bridge decks, train and ship components and lightweight protection systems. Impacts or other types of high-speed loading conditions are thus a relevant issue for several of these applications. There are, however, not many investigations published on the perforation of extruded aluminium panels covering experiments in combination with numerical analyses. This paper presents an experimental and numerical study on the perforation of AA6005-T6 aluminium panels impacted by ogival-nosed steel projectiles. The chosen panel has three triangular-shaped cells with a total depth of 130 mm. The wall thickness is 6 mm in the front and rear side plate, and 3 mm in the slanting webs. A rather comprehensive material test programme has been carried out in order to determine the material's response to dynamic loading. The experimental results were used to calibrate slightly modified versions of the Johnson-Cook constitutive relation and fracture criterion. 3D numerical simulations of the perforation process were then performed on a high-performance computer using the MPP version of the explicit finite element code LS-DYNA. In the simulations, the typical dimension of the elements was less than 1 mm. The numerical model is able to capture the main trends in the experiments in an adequate manner, and excellent agreement between numerical and experimental results is obtained.

  • 417.
    Calleecharan, Yogeshwarsing
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Contributions to the electromechanics of unbalanced magnetic pull in a synchronous hydropower generator2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Misalignment between the rotor geometrical axis and the geometrical stator axis in a hydropower generator is usually present at standstill and when the machine is under operation. Now, rotor-stator eccentricity in a rotating electrical machine is a harbinger to abnormal operating conditions of the machine. This rotor-stator eccentricity gives rise to a phenomenon called the unbalanced magnetic pull (UMP). Though the topic of UMP has been studied for more than a century, little attention has been paid to another phenomenon which is whirling and more specifically to non-synchronous whirling. Whereas the rotor-stator standstill misalignment can be cured to an acceptable level, a rotor when under operation normally entails whirling as well. Whirling is a reality in hydropower generators which are vertical machines and the latter are studied in this thesis work. It turns out that studying the effects of whirling in conjunction with the UMP can lift off pre-conceived ideas and hence provide a more qualitative and quantitative assessment of the effects of the nature and consequences of having a hydropower generator operating with UMP present. This thesis work provides simple theoretical conceptualisations that capture the phenomena of whirling and of the UMP, and purports to provide mechanical and electrical engineers with information on the necessity of studying these two phenomena simultaneously. With only the rotor eccentricity type considered in this work, the contributions are limited to mechanical dynamic simulations in the first part of the research work in addition to electromagnetic (EM) simulations in the second part of the research work. The validity of these EM simulations has been verified with an actual reported measurement. As for the mechanical dynamic analyses that cover the first part of the research work and which concern in essence one case of rotor eccentricity, valuable information such as the maximum rotor centre displacements inside the stator of the generator together with stability characteristics of the rotor motion are arrived at. These analyses indicate how stable the hydropower generator is under operation when UMP is present due to rotor eccentricity. It shows that one needs to consider both components of the UMP which are the radial UMP and the tangential UMP. Leaving out the tangential UMP component and/or considering a simplified whirling-independent model of the radial UMP lead(s) to a false representation of the dynamics of the generator when treated as a mechanical system. The analyses are new as a model that is used cares for both components of the UMP. In the second part of the research work, an electromechanics approach is preferred and emphasis is put on showing that important EM parameters such as force or the UMP, currents and ohmic losses are affected when non-synchronous whirling exists. The consideration of whirling as intimately linked to the UMP leads in the last stages of the research work to a robust and reliable method to compute the steady state UMP magnitude(s) up to sufficiently large eccentricities when two primary types of eccentricities, which are a purely static eccentricity and a purely dynamic eccentricity, co-exist. This novel computation method is of utmost importance and is a breakthrough in this area for four reasons: Firstly, there is no other work in the literature that has looked at mixed eccentricities motion of the geometric centre of the rotor in conjunction with simultaneous consideration of the UMP and the whirling phenomena. Secondly, it is fast as it is a semi-analytical method that rests on some previously done EM simulations which can be obtained with certain commercial EM field modelling software packages. Thirdly, it dispenses the analyst to have one of the rare contemporary commercial EM software products that can handle such intricate rotor centre motion since the proposed method rests upon less complicated EM simulations. And fourthly, it enables an analyst to obtain very good estimates of the UMP for a rotor centre motion that better mimics the true motion occurring in practice inside the stator of a hydropower generator. Altogether, the contributions in this thesis work can profoundly shape the strategies for better machine designs and analysis of the UMP without discounting previous knowledge that has been amassed since the end of the nineteenth century in this field. It is hoped that the research work carried out will help in the long interdisciplinary pursuit and allegiance to honing hydropower technology through creating an awareness of the need to study non-synchronous whirling effects as opposed to only looking at the usual synchronous whirling motion.

  • 418.
    Calleecharan, Yogeshwarsing
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    On the dynamics of an hydropower generator subjected to unbalanced magnetic pull: characterisation and analysis2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Eccentricity leading to unbalanced magnetic pull (UMP) in rotating electrical machines is a significant concern in industry. The UMP arises due to magnetic flux crossing the air-gap between the rotor and stator, and can be more intense than the useful peripheral force that the machine develops. Electric machines are the workhorses of any modern society and for over a century, the UMP phenomenon has been studied and this mainly by electrical engineers. Though, several refinements have been made in the equations describing this electromagnetic force to account for the effects such as saturation of iron parts and parallel circuits in the machine armature, the treatment of UMP is scarce in literature, and its characterisation and analysis remains a conundrum, and stays a subject of current research in electrical machinery design. Until a few years back, the UMP was thought to consist only of one component which acts in the radial direction. Though theoretical and mathematical developments have advanced to a very high level and are still forthcoming, there is generally no agreed model. The UMP model that tends to be utilised in industry only assumes the existence of the radial UMP and further simplifies the analysis by considering the maximum radial UMP stiffness to be applicable at all whirling angular velocities of the rotor. The present work comes in as furnishing two original contributions with emphasis on the understanding of the dynamics in lieu of considering both mechanical and electrical parameters that would create hard-to-analyse abstractions. First, it is shown that the simple model currently being used in industry may be fraught with risks. A new corrected model that accounts for both UMP components is thereby proposed in this work. This model is cast into stiffness terms and the separate effects of the radial UMP and that of the tangential UMP as well as their combined effects are explored quantitatively. So as to have tangible results that can be explained and the dynamics understood, a symmetrical Jeffcott rotor is used to simulate the newly proposed UMP model. Other pertinent simplifications include the use of a combined damping value for the rotor and bearings, the exclusion of unbalance force on the rotor due to mass eccentricity effect, the omission of the effects of saturation in the magnetic circuits together with assumption of linear behaviour of the UMP curves with eccentricity for low eccentricity values. Several important results surface from the analysis. It is found that the new UMP model is sensitive to forcing frequency in the rotor movements and that this sensitivity to forcing frequency increases with decreasing rotor system stiffness. Moreover, quasi-periodic motion in the rotor displacements is observed and it is noted that the rotor does not need to be forced by frequencies above its critical speed for this less desirable motion to occur.The second contribution in this thesis lays ground for stability consideration which is a cornerstone in the sound understanding of the design and operation of any machinery. Stability analysis is indispensable as disturbances do exist in real-life that can drive machines away from an equilibrium operating point. For the system at hand, it becomes essential to investigate the effect(s) of non-synchronous whirling on the stability of the system. Eigenvaluebased stability analysis is performed on the simple Jeffcott model and results show that damping, and stiffness of the rotor and of the bearings are important when non-synchronous whirling of the rotor comes into play. The original contributions in this work as depicted above comes primarily from the formulation and use of an UMP model that accounts for both the radial and the tangential UMP components. This allows unprecedented results to be arrived at that can be expected to be part of a crucial milestone in the generation of better rotor design parameters which can help to curb rotor-stator malfunction and can contribute in the design of long lasting rotors. This influential contribution will help in the long interdisciplinary pursuit and allegiance to honing hydropower technology.

  • 419.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Dynamics of a hydropower generator subjected to unbalanced magnetic pull2011Inngår i: Proceedings of the Institution of mechanical engineers. Part C, journal of mechanical engineering science, ISSN 0954-4062, E-ISSN 2041-2983, Vol. 225, nr 9, s. 2076-2088Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eccentricity leading to unbalanced magnetic pull (UMP) in electrical machines is a significant concern in industry. The UMP is known to be composed of two components: a radial component and a tangential one. Models that are used in industry tend to include the radial component alone. In this article, a Jeffcott rotor model together with a new UMP model that incorporates both radial and tangential UMP constituents is studied for an industrial hydropower generator. Characterizing the UMP as springs permits the model to inherit UMP stiffness contribution. Interesting dynamics are observed with the new model for a wide range of external forcing frequencies. It is shown firstly that the new UMP model is sensitive to forcing frequency in the rotor movements. Secondly, it is found that this sensitivity to forcing frequency increases with decreasing rotor system stiffness. Moreover, quasi-periodic motion in the rotor displacements is observed and it is noted that the rotor does not need to be forced by frequencies above its critical speed for this less desirable motion to occur. Thus, it becomes interesting to be able to account for the UMP stiffness contribution in order to curb machine malfunction which might result from these UMP forces

  • 420.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    On the dynamics of an hydropower generator subjected to unbalanced magnetic pull2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Eccentricity leading to unbalanced magnetic pull (UMP) in electrical machines is a significant concern in industry. The UMP is known to be composed of two components: A radial component and a tangential one. Models that are used in industry currently tend to include the radial component alone. In this paper, a Jeffcott rotor model together with a new UMP model that incorporates both radial and tangential UMP constituents is studied for an industrial hydropower generator. Characterising the UMP as springs permits the model to inherit UMP stiffness contribution. Interesting dynamics are observed with the new model for a wide range of external forcing frequencies. It is shown firstly that the new UMP model is sensitive to forcing frequency in the rotor movements. Moreover, complex dynamics in the displacements of the rotor are observed for some forcing frequencies and it is noted that the rotor does not need to be forced by frequencies above its critical speed for this less desirable motion to occur. Eigenvalue-based stability analysis is performed and shows that damping of the rotor and of the bearings are important when non-synchronous whirling of the rotor is considered. Accounting for both components of UMP is an important cornerstone in the generation of better rotor design parameters which can help to curb rotor-stator malfunction and can contribute in the design of long lasting rotors to the betterment of hydropower technology.

  • 421.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    On the dynamics of an hydropower generator subjected to unbalanced magnetic pull2011Inngår i: The Institution of Engineering and Technology 8th International Conference on Computation in Electromagnetics: (CEM 2011), Wroclaw, Poland, 11-14 April 2011, 2011, s. 50-51Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Eccentricity leading to unbalanced magnetic pull (UMP) in electrical machines is a significant concern in industry. The UMP is known to be composed of two components: A radial component and a tangential one. Models that are used in industry currently tend to include the radial component alone. In this paper, a Jeffcott rotor model together with a new UMP model that incorporates both radial and tangential UMP constituents is studied for an industrial hydropower generator. Characterising the UMP as springs permits the model to inherit UMP stiffness contribution. Interesting dynamics are observed with the new model for a wide range of external forcing frequencies. It is shown firstly that the new UMP model is sensitive to forcing frequency in the rotor movements. Moreover, complex dynamics in the displacements of the rotor are observed for some forcing frequencies and it is noted that the rotor does not need to be forced by frequencies above its critical speed for this less desirable motion to occur. Eigenvalue-based stability analysis is performed and shows that damping of the rotor and of the bearings are important when non-synchronous whirling of the rotor is considered. Accounting for both components of UMP is an important cornerstone in the generation of better rotor design parameters which can help to curb rotor-stator malfunction and can contribute in the design of long lasting rotors to the betterment of hydropower technology.

  • 422.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Stability analysis of an hydropower generator subjected to unbalanced magnetic pull2011Inngår i: IET Science, Measurement & Technology, ISSN 1751-8822, E-ISSN 1751-8830, Vol. 5, nr 6, s. 231-243Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eccentricity leading to unbalanced magnetic pull (UMP) in electrical machines is a significant concern in industry. The UMP is known to be composed of two components: A radial component and a tangential one. Models that are used in industry currently tend to include the radial component alone. In this study, a Jeffcott rotor model together with a new UMP model that incorporates both the radial and tangential UMP constituents is studied for an industrial hydropower generator. Characterising the UMP as springs permits the proposed model to inherit UMP stiffness contribution. It is shown firstly that the new UMP model is sensitive to forcing frequency in the rotor movements and secondly, that this sensitivity to forcing frequency increases with decreasing rotor system stiffness. Moreover, quasi-periodic motion in the rotor displacements is observed for some forcing frequencies and system stiffnesses. Eigenvalue-based stability analysis is performed and shows that damping and stiffness of the rotor and of the bearings are important when non-synchronous whirling of the rotor comes into play. Accounting for both UMP components is an important cornerstone in the generation of better rotor designs which can help to curb rotor-stator malfunction and can contribute in the design of long lasting rotors.

  • 423.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Brauer, J.P
    No-load electromagnetic simulations of a hydropower generator considering the effect of rotor whirling2015Inngår i: Balkan Journal of Electrical and Computer Engineering, ISSN 2147-284X, Vol. 3, nr 3, s. 124-134Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electromagnetic (EM) analysis of hydropower generators iscommon practice but there is little emphasis on studying the effect of rotorwhirling in the analysis. This paper explores the effect on electromagneticanalysis as the rotor is allowed to whirl both in forward and inbackward directions under no-load conditions. As a hydropower generatorrotor shaft can experience whirling when under eccentric operation,the objective is to examine how whirling can affect the unbalancedmagnetic pull (UMP), flux densities, damper currents, and ohmic lossesin a synchronous hydropower generator. These results are obtained ina commercial FEM-based EM field modelling software package thatallows various degrees of freedom in motion types and multiple motioncomponents to be set. It is seen that backward whirling tends to inducehigher eddy currents than forward whirling does.

  • 424.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jauregui, Ricardo
    DEE Universitat Politècnica de Catalunya , El Grupo de Compatibilidad Electromagnética GCEM, Barcelona.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Estimating forces in mixed eccentricities motion for purley dynamic eccentric rotor centre motion in a hydropower generator and their validation against EM simulations2015Inngår i: Balkan Journal of Electrical and Computer Engineering, ISSN 2147-284X, Vol. 3, nr 2, s. 78-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electromagnetic analysis of hydropower generators is commonpractice but there is little emphasis on studying the effect ofrotor whirling in the analysis. This paper demonstrates the use ofthe unbalanced magnetic pull (UMP) curves based on purely dynamiceccentricity motion for a wide range of whirling frequencies in theprediction of the steady state UMP in the case of mixed eccentricitiesmotion. The latter motion type is more realistic in practice. Actualelectromagnetic (EM) simulations are also carried out for these mixedeccentricities motion cases in order to verify the proposed method. Goodagreement between the UMP from the actual EM simulations and theUMP predictions are made when low eccentricities exist. The proposedmethod is thus very useful since firstly, very few EM software packagescan handle mixed eccentricities motion and secondly, since actual EMsimulations of intricate rotor centre motion are time-consuming, theproposed method is a big time saver. A modified feature selective validation(FSV) method, the FSV-UPC, is also applied to assess the similarities andthe differences in the force computations.

  • 425.
    Calleecharan, Yogeshwarsing
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jauregui, Ricardo
    DEE Universitat Politècnica de Catalunya , El Grupo de Compatibilidad Electromagnética GCEM, Barcelona.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Towards a general method for estimating the unbalanced magnetic pull in mixed eccentricities motion including sufficiently large eccentricities in a hydropower generator and their validation against EM simulations2013Inngår i: European Physical Journal: Applied physics, ISSN 1286-0042, E-ISSN 1286-0050, Vol. 63, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electromagnetic (EM) analysis of hydropower generators is common practice but rotor whirling is little studied. This paper suggests a novel semi-analytical method for estimating the steady state unbalanced magnetic pull (UMP) when the rotor centre is undergoing mixed eccentricities motion. The ability to estimate the UMP for mixed eccentricities motion in finite element method (FEM)-based modelling software packages is rare. The proposed methodology in its formulation takes advantage of the fact that a purely dynamic eccentricity motion including non-synchronous whirling and a purely static eccentricity motion can be more amenable to implement in existing FEM-based EM modelling software products for UMP estimation. After these initial separate UMP results are obtained, the proposed method can be applied for virtually any mixed eccentricities motion cases up to sufficiently large eccentricities for quick analysis instead of running the mixed eccentricities simulations directly in a FEM-based software package. Good agreement between the UMP from the actual EM mixed eccentricities motion simulations in a commercial FEM-based software package and the UMP estimations by the novel method is made for a wide range of eccentricities that may commonly occur in practice. A modified feature selective validation (FSV) method, the FSV-UPC, is applied to assess the similarities and the differences in the UMP computations

  • 426.
    Calmunger, Mattias
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Konstruktionsmaterial.
    Effect of temperature on mechanical response of austenitic materials2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Global increase in energy consumption and global warming require more energy production but less CO2emission. Increase in efficiency of energy production is an effective way for this purpose. This can be reached by increasing boiler temperature and pressure in a biomass power plant. By increasing material temperature 50°C, the efficiency in biomass power plants can be increased significantly and the CO2emission can be greatly reduced. However, the materials used for future biomass power plants with higher temperature require improved properties. Austenitic stainless steels are used in most biomass power plants. In austenitic stainless steels a phenomenon called dynamic strain aging (DSA), can occur in the operating temperature range for biomass power plants. DSA is an effect of interaction between moving dislocations and solute atoms and occurs during deformation at certain temperatures. An investigation of DSA influences on ductility in austenitic stainless steels and nickel base alloys have been done. Tensile tests at room temperature up to 700°C and scanning electron microscope investigations have been used. Tensile tests revealed that ductility increases with increased temperature for some materials when for others the ductility decreases. This is, probably due to formation of twins. Increased stacking fault energy (SFE) gives increased amount of twins and high nickel content gives a higher SFE. Deformation mechanisms observed in the microstructure are glide bands (or deformations band), twins, dislocation cells and shear bands. Damage due to DSA can probably be related to intersection between glide bands or twins, see figure 6 a). Broken particles and voids are damage mechanisms observed in the microstructure.

  • 427.
    Cameron, Christopher
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Lind, Eleonora
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Balancing structural and acoustic performance of sandwich panels for vehicle applications with topology, property, and size optimization2010Inngår i: 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010, ACCM-7 Organizing Committee , 2010, Vol. 2, s. 835-838Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Within this paper, a process for the design of a multifunctional sandwich body panel for vehicle applications is proposed. The method, presented with a case study, attempts to achieve a balance between structural and acoustic performance using numerical tools for topology optimization and combined size and property optimization. The goal of the work is to achieve an optimal distribution of traditional sandwich foam material and light weight acoustic foam within the core of the panel. The significance of the coupling between the panels inner face sheet and the acoustic foam is examined and proves to be a critical parameter in the design. An adaptation to existing topology optimization schemes is proposed to deal with the presence or absence of such a coupling. The results show promise in simplifying construction, reducing weight, and streamlining the assembly process.

  • 428.
    Cameron, Christopher
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik.
    Multi-Scale Structural-Acoustic Optimization of a Multi-Functional Vehicle Body Panel2009Konferansepaper (Annet vitenskapelig)
  • 429.
    Cante, J.
    et al.
    E.T.S. d’Enginyeries Industrial i Aeronáutica de Terrassa, Technical University of Catalonia (UPC), Campus Terrassa UPC.
    Dávalos, C.
    International Center for Numerical Methods in Engineering (CIMNE), C/. Gran Capitan s/n, 08034 , Barcelona.
    Hernández, J.A.
    E.T.S. d’Enginyeries Industrial i Aeronáutica de Terrassa, Technical University of Catalonia (UPC), Campus Terrassa UPC.
    Oliver, J.
    E.T.S. d’Enginyers de Camins, Canals i Ports de Barcelona, Technical University of Catalonia (UPC), Campus Nord UPC.
    Jonsén, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Gustafsson, Gustaf
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-Åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    PFEM-based modeling of industrial granular flows2014Inngår i: Computational Particle Mechanics, ISSN 2196-4378, Vol. 1, nr 1, s. 47-70Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The potential of numerical methods for the solution and optimization of industrial granular flows problems is widely accepted by the industries of this field, the challenge being to promote effectively their industrial practice. In this paper, we attempt to make an exploratory step in this regard by using a numerical model based on continuous mechanics and on the so-called Particle Finite Element Method (PFEM). This goal is achieved by focusing two specific industrial applications in mining industry and pellet manufacturing: silo discharge and calculation of power draw in tumbling mills. Both examples are representative of variations on the granular material mechanical response—varying from a stagnant configuration to a flow condition. The silo discharge is validated using the experimental data, collected on a full-scale flat bottomed cylindrical silo. The simulation is conducted with the aim of characterizing and understanding the correlation between flow patterns and pressures for concentric discharges. In the second example, the potential of PFEM as a numerical tool to track the positions of the particles inside the drum is analyzed. Pressures and wall pressures distribution are also studied. The power draw is also computed and validated against experiments in which the power is plotted in terms of the rotational speed of the drum.

  • 430.
    Canton, Jacopo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Auteri, F.
    Carini, M.
    Linear global stability of two incompressible coaxial jets2017Inngår i: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 824, s. 886-911Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The linear stability of two incompressible coaxial jets, separated by a thick duct wall, is investigated by means of both a modal and a non-modal approach within a global framework. The attention is focused on the range of unitary velocity ratios for which an alternate vortex shedding from the duct wall is known to dominate the flow. In spite of the inherent convective nature of jet flow instabilities, such behaviour is shown to originate from an unstable global mode of the dynamics linearised around the axisymmetric base flow. The corresponding wavemaker is located in the recirculating-flow region formed behind the duct wall. At the same time, the transient-growth analysis reveals that huge amplifications (up to 20 orders of magnitude) of small flow perturbations at the nozzle exit can occur in the subcritical regime, especially for high ratios between the outer and the inner velocities.

  • 431.
    Cao, Cejun
    et al.
    Tianjin Univ, Peoples R China; Jinan Univ, Peoples R China.
    Li, Congdong
    Tianjin Univ, Peoples R China; Jinan Univ, Peoples R China.
    Yang, Qin
    Sichuan Normal Univ, Peoples R China.
    Liu, Yang
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten. Jinan Univ, Peoples R China; Univ Vaasa, Finland.
    Qu, Ting
    Jinan Univ, Peoples R China.
    A novel multi-objective programming model of relief distribution for sustainable disaster supply chain in large-scale natural disasters2018Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 174, s. 1422-1435Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To save lives and reduce suffering of victims, the focus of this paper is to design the strategies of relief distribution regarding beneficiary perspective on sustainability. This problem is formulated as a multi objective mixed-integer nonlinear programming model to maximize the lowest victims perceived satisfaction, and minimize respectively the largest deviation on victims perceived satisfaction for all demand points and sub-phases. Then, genetic algorithm is proposed to solve this mathematical model. To validate the proposed methodologies, a case study from Wenchuan earthquake is illustrated. Computational results demonstrate genetic algorithm here can achieve the trade-off between solution quality and computation time for relief distribution with the concern of sustainability. Furthermore, it indicates that the methodology provides the tools for decision-makers to optimize the structure of relief distribution network and inventory, as well as alleviate the suffering of victims. Increasingly, this paper expects to not only validate the proposed model and method, but also highlight the importance and urge of considering beneficiary perspective on sustainability into relief distribution problem. (C) 2017 Elsevier Ltd. All rights reserved.

  • 432.
    Carlson, Philip
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörsvetenskap och fysik, Science, Mathematics and Engineering Education Research (SMEER).
    Konstruktions- och Materialförbättring hos Superkritiska Ventiler2015Independent thesis Basic level (university diploma), 15 poäng / 22,5 hpOppgave
  • 433. Carlsson, J.
    et al.
    Lundberg, Bengt
    Luleå tekniska universitet.
    Sundin, Karl-Gustaf
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Determination of force, particle velocity and related quantities in a dynamically loaded non-uniform rod from strain histories at two cross sections1990Inngår i: Experimental mechanics : 9th International conference : Papers., Lyngby: Technical University of Denmark , 1990Konferansepaper (Fagfellevurdert)
  • 434.
    Carlsson, J.
    et al.
    Luleå tekniska universitet.
    Sundin, Karl-Gustaf
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Lundberg, Bengt
    Luleå tekniska universitet.
    Method for determination of in-hole dynamic force-penetration data from two-point strain measurement on a percussive drill rod1990Inngår i: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, ISSN 0148-9062, E-ISSN 1879-2073, Vol. 27, nr 6, s. 553-558Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of the present investigation is to establish a testing method suited for determination of in-hole dynamic force-penetration data for non-uniform standard percussive drill rod-bit configurations. The method is based on a version of the method of two-point strain measurement, which permits non-uniform rods, i.e. rods with variable characteristic impedance. This version allows normal force and particle velocity to be evaluated at an arbitrary cross-section of a homogenous non-uniform elastic rod from strain measurements performed at two different cross-sections of the same rod. The main problem of this investigation is to assess whether the influence of threads can be considered insignificant. As a part of the study force-penetration relationships have been determined for the penetration of a standard Sandvik Rock Tools button bit into Swedish Bohus granite.

  • 435.
    Carlsson, Janne
    Luleå tekniska universitet.
    Analysis of elastic waves in rods from two-point strain measurement: extension tin non-uniform systems and applications to bit-rock interaction and rotational mobility1989Licentiatavhandling, monografi (Annet vitenskapelig)
  • 436.
    Carlsson, Janne
    Luleå tekniska universitet.
    Methods for mechanical testing based on analysis of elastic waves in rods1992Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis summarizes six papers on development and applications of a method to evaluate the normal force and particle velocity at any cross-section of a nonuniform rod from measurements of strain at two different cross-sections. In Paper A the method is developed. It is an extension of that developed by Lundberg and Henchoz for uniform rods. Theoretical results, based on onedimensional elastic wave theory, are provided for the general case as well as for cases of piecewise constant characteristic impedance. In Paper B an extension of the method has been used to determine the characteristic impedance function for an initially uniform rod heated at one end. The results show that force and particle velocity at the heated end can be evaluated with the same accuracy as for a uniform rod. In Paper C the method has been used to extend the split-Hopkinson pressure bar technique to testing of high-strength materials such as ceramics. The technique gives an accurate value of the fracture stress and a fair approximation of the strain rate. A modified Hopkinson pressure bar has been used in Paper D to determine the dynamic fracture toughness from the load-point displacement of a three-point bend specimen. The latter quantity was assumed to be proportional to the stress intensity factor. The results agreed well with those obtained from strain measurement near the notch tip. From the penetration tests made in Paper E it was concluded that the method established allows force-penetration data to be determined satisfactorily for standard threaded rod-bit configurations. Paper F presents a rod transducer for rotational point mobility. The tests showed that the transducer works satisfactorily in frequency and mobility ranges of approximately two decades.

  • 437.
    Carlsson, Jenny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Dynamic crack growth in porous materials2017Konferansepaper (Annet vitenskapelig)
  • 438.
    Carlsson, Jenny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Snabba brott i trä2018Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 439.
    Carlsson, Jenny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Crack dynamics and crack tip shielding in a material containing pores analysed by a phase field method2019Inngår i: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 206, s. 526-540Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many naturally occurring materials, such as wood and bone, have intricate porous micro-structures and high stiffness and toughness to density ratios. Here, the influence of pores in a material on crack dynamics in brittle fracture is investigated. A dynamic phase field finite element model is used to study the effects of pores with respect to crack path, crack propagation velocity and energy release rate in a strip specimen geometry with circular pores. Four different ordered pore distributions are considered, as well as randomly distributed pores. The results show that the crack is attracted by the pores; this attraction is stronger when there is more energy available for crack growth. Crack propagation through pores also enables higher crack propagation velocities than are normally seen in strip specimens without pores (i.e. homogeneous material), without a corresponding increase in energy release rate. It is further noticed that as the porosity of an initially solid material increases, the crack tip is increasingly likely to become shielded or arrested, which may be a key to the high relative strength often exhibited by naturally occurring porous materials. We also find that when a pore is of the same size as the characteristic internal length then the pore does not localise damage. Since the characteristic internal length only regularises the damage field and not the strain end kinetic energy distributions, crack dynamics are still affected by small pores.

  • 440.
    Carlsson, Jenny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Dynamic crack propagation and crack tip shielding in porous materials analyzed by the phase field method for fracture2018Konferansepaper (Annet vitenskapelig)
  • 441.
    Carlsson, Jenny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Dynamic crack propagation in wood fibre composites analysed by high speed photography and a dynamic phase field model2018Inngår i: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 144-145, s. 78-85Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using an experimental setup, with a high-speed camera to track crack tip velocity, dynamic fracture is studied in wood fibre polylactic acid (PLA) composite and pure PLA. The experiments are analysed quantitatively in terms of the relation between energy release rate and crack tip velocity, and qualitatively in terms of branching occurrence and fracture surface appearance. Branching occurs frequently in PLA specimens but not in wood fibre composite specimens, in spite of high energy release rates. Scanning electron microscopy images of the fracture surfaces show that the fracture surfaces in wood fibre composite materials are rugged and uneven compared to PLA, whose surfaces are smoother. The experimental results are compared to numerical results, obtained using a dynamic phase field finite element model. Simulations correlate well with experiments with respect to the relation between energy release rate and crack tip velocity. For PLA, the simulations also predict branching correctly, but for wood fibre composites, the simulations slightly over-predict the amount of branching and point to a need for further development of fracture models in order to better capture the constitutive behaviour of these heterogeneous materials.

  • 442.
    Carlsson, Jenny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Fracture nucleation and continued crack growth on the cell scale in wood analysed by as high-resolution finite element model2016Inngår i: The Eccomas Congress 2016 Proceedings, 2016Konferansepaper (Fagfellevurdert)
  • 443.
    Carlsson, Jenny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    High-velocity crack speed in wood fibre composites: an experimental and numerical study2017Inngår i: CFRAC 2017, International Conference on Computational Fracture and Failure of Materials and Structures, Book of abstracts, 2017, s. 155-Konferansepaper (Fagfellevurdert)
  • 444.
    Carlsson, Jenny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Joffre, Thomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Isaksson, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Dynamic crack propagation in wood fibre composites2017Inngår i: Svenska Mekanikdagar 2017, Uppsala 12 – 13 juni, 2017Konferansepaper (Fagfellevurdert)
  • 445.
    Carlsson, Markus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik.
    Konstruktion av beslag med dörrfunktion till spridarlucka2013Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis was performed at Zetterbergs Industri AB. Zetterbergs is designing, building and mounts body systems for trucks, including dumpers and tippers. The assignment for the thesis was to design a door hinge for a spreader gate. The spreader gate is the top of the two tailgates on a dumper or tipper and opens back and outwards when tipping the cargo. The spreader gate controls the mass flow of the material being tipped. Zetterbergs want to offer their customers an opportunity to also open the spreader gate as a door and place it along the outside of the tipper to get easier access to the platform when loading equipment. They already have an existing solution for both the tipper and the dumper, but there is a need to improve and coordinate these solutions. The existing solution is not entirely rigid which causes problems of sagging when used, and a result of this is heavy lifting for the operator.

     

    The process with designing a new hinge began with an initial study where, among others, the existing hinge and prototype solutions of the hinge at Zetterbergs were examined. To get to understand the process and which parts that needed to be taken into consideration when designing, a participation in the production was made. The initial study was finalized with the preparation of a user and technical specification.

     

    Following the initial study several concepts was generated with a method called “ the five step method”.  Afterwards the concepts were evaluated and compared which lead to the selection of one of the concepts for a final design.

     

    The result of this thesis is a door hinge with tree different configurations. Those three configurations were made to fit the combinations between tipper and dumper as well as aluminum and steel hatch. The hinges are similar to each other and only a few details separate them. All components in the door hinge are adjusted for the production at Zetterbergs. The door hinge is designed in a way that prevents the operator from using it improperly.

  • 446.
    Carlsson, Per
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lycksam, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Gren, Per
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Gebart, Rikard
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wiinikka, Henrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Iisa, Kristiina
    National Renewable Energy Laboratory, Golden, Colorado.
    High-speed imaging of biomass particles heated with a laser2013Inngår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 103, s. 278-286Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work two types of lignocellulosic biomass particles, European spruce and American hardwood (particle sizes from 100 μm to 500 μm) were pyrolysed with a continuous wave 2 W Nd:YAG laser. Simultaneously a high-speed camera was used to capture the behavior of the biomass particle as it was heated for about 0.1 s. Cover glasses were used as a sample holder which allowed for light microscope studies after the heating. Since the cover glasses are not initially heated by the laser, vapors from the biomass particle are quenched on the glass within about 1 particle diameter from the initial particle. Image processing was used to track the contour of the biomass particle and the enclosed area of the contour was calculated for each frame.The main observations are: There is a significant difference between how much surface energy is needed to pyrolyses the spruce (about 75% more) compared to the hardwood. The oil-like substance which appeared on the glass during the experiment is solid at room temperature and shows different levels of transparency. A fraction of this substance is water soluble. A brownish coat is seen on the unreacted biomass. The biomass showed insignificant swelling as it was heated. The biomass particle appears to melt and boil at the front that is formed between the laser beam and the biomass particle. The part of the particle that is not subjected to the laser beam seems to be unaffected.

  • 447.
    Carlsson, Susanna
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    Larsson, Per-Lennart
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.).
    On Microindentation of Viscoelastic Polymers1998Inngår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 17, nr 1, s. 49-75Artikkel i tidsskrift (Fagfellevurdert)
  • 448.
    Carlsson, Torgny E.
    et al.
    Swedish Defence Research Agency, FOI.
    Mattsson, Roger
    Luleå tekniska universitet.
    Gren, Per
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Elfsberg, Mattias
    Swedish Defence Research Agency, FOI.
    Tegner, Jon
    Swedish Defence Research Agency, FOI.
    Combination of schlieren and pulsed TV holography in the study of a high-speed flame jet2006Inngår i: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 44, nr 6, s. 535-554Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents studies of the propagation of a high-speed turbulent flame jet of an air/hydrogen gas mixture. The experimental results are recorded with the schlieren and the pulsed TV holography method. These methods are compared and combined to benefit from the advantages of each of them. Abel inversion has been used to achieve three-dimensional information i.e. refractive index distributions. Evaluation, calibration and Abel inversion algorithms are described together with experimental results. The results obtained from the different techniques show remarkable similarities concerning both qualitative and quantitative aspects.

  • 449.
    Casellas, Daniel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Frómeta, David
    Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa, Spai.
    Lara, Toni
    undació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa, Spai.
    Molas, Silvia
    undació CTM Centre Tecnològic, Plaça de la Ciència 2, 08243 Manresa, Spai.
    Jonsén, Pär
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Golling, Stefan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Oldenburg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    A fracture mechanics approach to develop high crash resistant microstructures by press hardening2017Inngår i: 6th International Conference Hot Sheet Metal Forming of High-Performance Steel CHS2: June 4-7 2017, Atlanta, Georgia, USA : proceedings / [ed] Mats Oldenburg, Braham Prakash, Kurt Steinhoff, Warrendale, PA: Association for Iron & Steel Technology, AIST , 2017, s. 101-107Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Crashworthiness is a relevant engineering property for car parts. However it is not easy to measure at laboratory scale and complex impact tests have to be carried out to determine it. Crash resistance for high strength steel is commonly evaluated in terms of cracking pattern and energy absorption in crashed specimens. Accordingly, the material resistance to crack propagation, i.e. the fracture toughness, could be used to rank crashworthiness. It has been proved in a previous work by the authors, so the measure of fracture toughness, in the frame of fracture mechanics in small laboratory specimens, would allow determining the best microstructure for crash resistance parts. Press hardening offers the possibility to obtain a wide range of microstructural configurations, with different mechanical properties. So the aim of this work is to evaluate the fracture toughness following the essential work of fracture methodology for ferrite-pearlite, bainite, ferrite-bainite, martensite and martensite-bainite microstructures. Results showed that bainitic microstructures have high fracture toughness, similar to TWIP and CP steels, which allows pointing them as potential candidates for obtaining high crash resistance in parts manufactured by press hardening.

  • 450.
    Casellas, Daniel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Lara, Antoni
    Fundació CTM Centre Tecnològic, Manresa.
    Frómeta, David
    Fundació CTM Centre Tecnològic, Manresa.
    Gutiérrez, David
    Fundació CTM Centre Tecnològic, Manresa.
    Molas, Silva
    Fundació CTM Centre Tecnològic, Manresa.
    Pérez, Lluís
    Fundació CTM Centre Tecnològic, Manresa.
    Rehrl, Johannes
    Voestalpine Stahl GmbH, Linz.
    Suppan, Clemens
    Voestalpine Stahl GmbH, Linz.
    Fracture Toughness to Understand Stretch-Flangeability and Edge Cracking Resistance in AHSS2017Inngår i: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 48A, nr 1, s. 86-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The edge fracture is considered as a high risk for automotive parts, especially for parts made of advanced high strength steels (AHSS). The limited ductility of AHSS makes them more sensitive to the edge damage. The traditional approaches, such as those based on ductility measurements or forming limit diagrams, are unable to predict this type of fractures. Thus, stretch-flangeability has become an important formability parameter in addition to tensile and formability properties. The damage induced in sheared edges in AHSS parts affects stretch-flangeability, because the generated microcracks propagate from the edge. Accordingly, a fracture mechanics approach may be followed to characterize the crack propagation resistance. With this aim, this work addresses the applicability of fracture toughness as a tool to understand crack-related problems, as stretch-flangeability and edge cracking, in different AHSS grades. Fracture toughness was determined by following the essential work of fracture methodology and stretch-flangeability was characterized by means of hole expansions tests. Results show a good correlation between stretch-flangeability and fracture toughness. It allows postulating fracture toughness, measured by the essential work of fracture methodology, as a key material property to rationalize crack propagation phenomena in AHSS.

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