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  • 101.
    De Backer, Jeroen
    et al.
    Högskolan Väst, Sweden.
    Bolmsjö, Gunnar
    University West, Trollhättan, Sweden.
    Christiansson, Anna-Karin
    Högskolan Väst, Sweden.
    Temperature control of robotic friction stir welding using the thermoelectric effect2014In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 70, no 1-4, p. 375-383Article in journal (Refereed)
    Abstract [en]

    Friction stir welding (FSW) of non-linear joints receives an increasing interest from several industrial sectors like automotive, urban transport and aerospace. A force-controlled robot is particularly suitable for welding complex geometries in lightweight alloys. However, complex geometries including three-dimensional joints, non-constant thicknesses and heat sinks such as clamps cause varying heat dissipation in the welded product. This will lead to changes in the process temperature and hence an unstable FSW process with varying mechanical properties. Furthermore, overheating can lead to a meltdown, causing the tool to sink down into the workpiece. This paper describes a temperature controller that modifies the spindle speed to maintain a constant welding temperature. A newly developed temperature measurement method is used which is able to measure the average tool temperature without the need for thermocouples inside the tool. The method is used to control both the plunging and welding operation. The developments presented here are applied to a robotic FSW system and can be directly implemented in a production setting.

  • 102.
    de Borst, Karin
    et al.
    University of Glasgow, UK.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Structure-€“function relationships in hardwood: Insight from micromechanical modelling2014In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 345, p. 78-91Article in journal (Refereed)
    Abstract [en]

    Abstract A micromechanical model is presented that predicts the stiffness of wood tissues in their three principal anatomical directions, across various hardwood species. The wood polymers cellulose, hemicellulose, and lignin, common to all wood tissues, serve as the starting point. In seven homogenisation steps, the stiffnesses of these polymers are linked to the macroscopic stiffness. The good agreement of model predictions and corresponding experimental data for ten different European and tropical species confirms the functionality and accuracy of the model. The model enables investigating the influence of individual microstructural features on the overall stiffness. This is exploited to elucidate the mechanical effects of vessels and ray cells. Vessels are shown to reduce the stiffness of wood at constant overall density. This supports that a trade-off exists between the hydraulic efficiency and the mechanical support in relation to the anatomical design of wood. Ray cells are shown to act as reinforcing elements in the radial direction.

  • 103.
    de Borst, Karin
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Wikete, Christoph
    Vienna University of Technology, Austria.
    Microstructure-€“stiffness relationships of ten European and tropical hardwood species2012In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 177, no 2, p. 532-542Article in journal (Refereed)
    Abstract [en]

    Hardwood species exhibit a huge anatomical variability. This makes them perfect study objects for exploring relations between structural features at different length scales and corresponding stiffness properties of wood. We carry out microscopic analysis, nanoindentation tests, as well as macroscale ultrasonic and quasi-static tension tests and build a complete set of microstructural and corresponding micromechanical data of ten different (European and tropical) hardwood species. In addition, we apply micromechanical modeling to further elucidate the individual influences of particular structural features, which might appear only in a superimposed manner in experiments. The test results confirm the dominant influences of the microfibril angle on the stiffness at cell wall level and of density at the macroscopic scale. Vessels and ray cells affect the macroscopic stiffness of the wood tissue not only through their content, but also through their arrangement and shape: A ring-porous structure results in comparably higher longitudinal but lower radial stiffness than a diffuse-porous one. As for ray cells, large and particularly compactly shaped bundles might reduce the stiffness in tangential direction because of the fiber deviations they cause. Moreover, vessel and ray content might affect the relation between nanoindentation modulus and density-corrected macroscopic longitudinal stiffness.

  • 104.
    Dioszegi, Attila
    et al.
    Jönköping University.
    Svidro, Peter
    Jönköping University.
    Elmquist, Lennart
    SinterCast AB, Katrineholm.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Defect formation mechanisms in lamellar graphite iron related to the casting geometry2016In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 29, no 5, p. 279-285Article in journal (Refereed)
    Abstract [en]

    Although lamellar cast iron has been used in advanced applications for about 20 years, our knowledge about the mechanisms affecting microstructure and defect formation is relatively limited. The present paper summarises some solidification-related phenomena from a series of recently published peer-reviewed papers and scientific theses and suggests a mechanism of defect formation which is dependent on the shape of the solidifying casting geometry. When shrinkage porosity or metal expansion penetration occurs, evidence of material transport in the intergranular zone of primary equiaxed austenite grains in the casting and in the intergranular regions between the sand grains in the mould material is seen. Material transport occurs across the casting-mould interface, where the existence of or the permeability of the primary columnar zone determines if material transport can take place.

  • 105.
    Diószegi, Attila
    et al.
    Jönköping University.
    Dugic, Izudin
    Jönköping University.
    The Mechanism of Metal Expansion Penetration in Gray Cast Iron2006Conference paper (Refereed)
  • 106.
    Diószegi, Attila
    et al.
    Jönköping University.
    Dugic, Izudin
    Jönköping University.
    Svensson, Ingvar L
    Jönköping University.
    Metal Expansion Penetration on Concave Casting Surfaces of Grey Cast Iron Cylinder Heads2007In: Transactions of the American Foundry Society, Vol. 115, p. 609-615Article in journal (Refereed)
  • 107.
    Diószegi, Attila
    et al.
    Jönköping University.
    Dugic, Izudin
    Jönköping University.
    Svensson, Ingvar L
    Jönköping University.
    Penetrationsfehler an konkaven Gussteiloberflächen von Grauguss-Zylinderköpfen (Penetration errors casting concave surfaces of grey cast iron cylinder heads)2007In: Giesserei-Praxis, ISSN 0016-9781, Vol. 58, no 11, p. 450-454Article in journal (Other academic)
  • 108.
    Diószegi, Attila
    et al.
    Jönköping University.
    Elmquist, Lennart
    Jönköping University.
    Orlenius, Jessica
    Högskolan i Jönköping, JTH. Forskningsområde Material och tillverkning - gjutning.
    Dugic, Izudin
    Jönköping University.
    Defect Formation at Casting of Gray Iron Components2009In: Proceedings of the Carl Loper Cast Iron Symposium, Madison, Wisconsin, US, 2009Conference paper (Refereed)
  • 109.
    Diószegi, Attila
    et al.
    Jönköping University.
    Elmquist, Lennart
    Jönköping University.
    Orlenius, Jessica
    Jönköping University.
    Dugic, Izudin
    Jönköping University.
    Defect Formation of Gray Iron Casting2009In: International Journal of metalcasting, ISSN 1939-5981, E-ISSN 2163-3193, Vol. 3, no 4, p. 49-58Article in journal (Refereed)
    Abstract [en]

    Cast iron is one of the oldest technical alloys used for creating objects. Foundrymen from the very beginning of casting was fighting to avoid casting defects. In the beginning a successfully performed casting was associated with witchcraft. Cast component producers suffer yearly substantial expenses due to rejecting or repairing castings. The present work will summarize research efforts to understand formation mechanisms of defects, performed in collaboration with Swedish foundries during the last years. The presented work will focus on defects, specific casting of gray iron components. Studied defects are gas porosity, shrinkage porosity and metal expansion penetration. Novell experimental set up has been developed or existing methods has been improved to study defect formation mechanisms. Today we can realize that casting without defects are possible only by approaching the defect formation mechanism with multidisciplinary science.

  • 110.
    Diószegi, Attila
    et al.
    Jönköping University, Sweden.
    Svidró, Peter
    Jönköping University, Sweden.
    Elmquist, Lennart
    Jönköping University, Sweden.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Defect formation mechanisms in lamellar cast iron related to the casting geometry2015In: Advances in the science and engineering of casting solidification: An MPMD symposium honoring Doru Michael Stefanescu / [ed] Laurentiu Nastac, Baicheng Liu, Hasse Fredriksson, Jacques Lacaze, Chun-Pyo Hong, Adrian Catalina, Andreas Buhrig-Polaczek, Daan M. Maijer, Charles Andrew Monroe, Adrian Sabau, Roxana Ruxanda, Alan A. Luo, Subhayu Sen, Attila Diószegi, Hoboken, NJ: John Wiley & Sons, 2015, p. 251-259Conference paper (Refereed)
    Abstract [en]

    Although lamellar cast iron has been used in advanced applications for about twenty years, our knowledge about the mechanisms affecting microstructure and defect formation is relatively limited. The present paper summarizes some solidification related phenomena from a series of recently published peer reviewed papers and scientific theses and suggests a mechanism of defect formation which is dependent on the shape of the solidifying casting geometry. When shrinkage porosity or metal expansion penetration occurs evidence of material transport in the intergranular zone of primary equiaxed austenite grains in the casting and in the intergranular regions between the sand grains in the mold material is seen. Material transport occurs across the casting-mold interface where the existence of or the permeability of the primary columnar zone determines if material transport can take place.

  • 111.
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    A combined material model for plasticity and fracture for wood2015In: Proceedings of the EUROMECH Colloquium 556 on Theoretical, Numerical, and Experimental Analyses in Wood Mechanics / [ed] Michael Kaliske, 2015Conference paper (Refereed)
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  • 112.
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Proposal for a Failure Surface for Orthotropic Composite Materials2014In: / [ed] Oñate, Eugenio and Oliver, Xavier and Huerta, Antonio, 2014Conference paper (Refereed)
    Download full text (pdf)
    fulltext
  • 113.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Tuvendal, Helena
    Södra skogsägarna.
    Henrik, Oxfall
    Swerea.
    Serrano, Erik
    Lunds Tekniska Högskola.
    FBBB 4.3 Biobaserade skivmaterial: Experimentella undersökningar2018Report (Other academic)
    Abstract [sv]

    Rapporten är del av projektet Framtidens Byggande och Boende (FBBB), delprojekt 4.3 "Biobaserade skivmaterial". I denna rapport presenteras resultatet av de mekaniska drag- och böjprov såsom DTMA analys. Materialet ”Durapulp”, som tillverkas av Södra, är referensmaterialet i delprojektet. Provkroppar av Durapulp producerades med olika tillverkningsmetoder för att se skillnader i beteenden. Referensmaterialen är trä-baserade skivmaterial som anses vanligt förekommande i byggskeendet.

    Download full text (pdf)
    fulltext
  • 114.
    Druenert, F.
    et al.
    Univ Jena, Germany.
    Blanz, M.
    Univ Jena, Germany;Univ Highlands & Isl, UK.
    Pollok, K.
    Univ Jena, Germany.
    Pan, Z.
    Univ Jena, Germany.
    Wondraczek, L.
    Univ Jena, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Copper-based opaque red glasses - Understanding the colouring mechanism of copper nanoparticles in archaeological glass samples2018In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 76, p. 375-381Article in journal (Refereed)
    Abstract [en]

    Red opaque glasses of two different sites in central Germany, a medieval glassworks in Glashutten, Taunus Mountains, and an early modern glassworks in Wieda, Harz Mountains, were analysed with regard to their optical appearance. By scanning electron microscopy and X-ray diffraction, metallic copper nanoparticles were identified as a conspicuous constituent in these glasses. In addition, similar opaque red glasses were reproduced in the laboratory in order to better understand the manufacturing process. Detailed analysis of the optical scattering was conducted in order to evaluate the role of Cu-0 nanoparticles in the colouring mechanism relative to other possible reasons of colouration. We find clear differences between the possible contributions of Cu2O (cuprite) particles and metallic copper (Cu-0) nanoparticles. Through simulated backscattering spectra we were able to calculate an average copper particle radius in the archaeological glass samples resulting in a value of up to 95 nm, which matches well the results of SEM investigation (minimum 65 nm). Using the methods we applied in this study, it becomes possible to reconstruct various processing conditions as they were applied in medieval manufacture of these particular materials. (C) 2018 Elsevier B.V. All rights reserved.

  • 115.
    Druenert, Ferdinand
    et al.
    Univ Jena, Germany.
    Palamara, Eleni
    Univ Peloponnese, Greece.
    Zacharias, Nikolaos
    Univ Peloponnese, Greece.
    Wondraczek, Lothar
    Univ Jena, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Ancient Roman nano-technology: Insight into the manufacture of mosaic tesserae opacified by calcium antimonate2018In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 38, no 14, p. 4799-4805Article in journal (Refereed)
    Abstract [en]

    Opaque mosaic glass tesserae containing calcium antimonates from Ancient Messene, Greece (1st-4th century CE) were investigated by scanning electron microscopy, Raman spectroscopy and X-ray diffraction. Both trigonal CaSb2O6 and cubic Ca2Sb2O2, with crystallite diameters below 1 pm, were identified as opacifying agents. To better understand ancient technologies, we prepared model glasses that were opacified by crystallisation via a secondary heat treatment, by direct crystallisation during the melting process, or by the addition of pre-reacted calcium antimonate to a base glass. We found that direct crystallisation replicated the antique glass artefacts most accurately. We demonstrated that 0.2 wt% of nucleating agents like TiO2 and SnO2 already exert significant influence on the crystallisation behaviour of calcium antimonates. Secondary scattering centres such as silica and carbonates contribute to the optical appearance. Concurrently, we reproduced opaque white glass ceramics in a reconstructed, wood-fired, Roman-type glass furnace built by Wiesenberg (2014).

  • 116.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ductile iron for the wind power industry2013Conference paper (Refereed)
    Abstract [en]

    The generation of electricity in the Europe from wind-powered turbines is increasing and the most important challenges for the wind turbine manufacturers are linked to the development of larger and more effective wind turbines. Cast iron is today used in central parts of a wind turbine construction and this is a growing market for Swedish foundries. The specifications and requirements applied for the cast iron components are among the most stringent used within the iron foundry branch. A problem for the production of these large components can be too high pearlite content in the metal matrix, thereby deteriorating mechanical properties. Because of this reason there are just a few iron foundries in Sweden that are able to cast the required high quality cast iron components.

    The project work has focused on reducing the pearlite stabilizing blanks into the melt and to improve the inoculation process. The project has shown that systematic work with the melt composition and inoculation may provide a much improved structure and thus better properties.

  • 117.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Effect of Casting Temperature on the Surface Finish of Grey Iron Castings2019In: Materials Processing Fundamentals 2019 / [ed] Lambotte G., Lee J., Allanore A., Wagstaff S., Springer, 2019, p. 87-95Conference paper (Refereed)
    Abstract [en]

    One of the most common surface defects in sand casting of grey cast iron is caused by metal penetration into the sand mould. Metal penetration is a surface condition in which metal or metal oxides have filled the voids between sand grains to various depth without displacing them, thus yielding a phase of sand grains surrounded by metal and frequently by mould–metal reaction products. The penetration is often so severe that casting components are beyond the point of economical rework and must be scrapped. This experimental work has focused on reducing metal penetration on casting component on a production scale. The casting component produced has strongly affected by sand sintering metal penetration. A series of simulations were performed with the casting simulation program MagmaSoft® in order to investigate the solidification characteristics as well as the porosity formation in the casting component. 

  • 118.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Effect of cooling rate on the casting defects of high chromium white cast iron for the impellers2015In: Zbornik povzetkov referatov 55. mednarodnega livarskega posvetovanja, Portorož 2015 / [ed] Alojz Križman; Mirjam Jan-Blažič; Martin Debelak; Peter Schumacher; Rüdiger Deike, Ljubljana: Društvo livarjev Slovenije , 2015, p. 35-Conference paper (Refereed)
    Abstract [en]

    One of the oldest high alloys white cast irons is produced commercially when the chromium content is between 23 and 28 %. The high-chromium white irons have excellent abrasion resistance and are used effectively in slurry pumps, brick molds, coal-grinding mills, rolling mill rolls, shot blasting equipment, and components for quarrying, hard-rock mining and milling.

    The specifications and requirements applied for the white cast iron components are among the most stringent used within the iron foundry branch. One of the biggest problems for the production of these components is hot tearing or hot cracking, or hot shortness. Irrespective of the name, this phenomenon represents the formation of an irreversible failure (crack) in the still semisolid casting.

    This paper will show a study of the effect of cooling rate on the cracks. The procedure to achieve this was to study one casting component, impeller, in a production scale using different cooling rate after pouring.

    In this work it has been shown that the solidification rate has a strong effect on the hot cracking.

  • 119.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Effect of molybdenum content and pouring temperature on the casting defects of high chromium white cast iron for the impellers2014In: Proceeding book of the 14th international foundrymen conference / [ed] Unkić, Faruk, Sisak, Croatia: University of Zagreb, Faculty of Metallurgy , 2014, , p. 10p. 17:1-17:8Conference paper (Other academic)
    Abstract [en]

    White cast iron components are today used in central parts for pumps. The specifications and requirements applied for the white cast iron components are among the most stringent used within the iron foundry branch. One of the problems for the production of these components can be cracks. Because of this reason there are just a few iron foundries in Sweden that are able to cast the required high quality white cast iron components.

    The project work has focused on reducing the cracks and to improve the machining properties of the casting. The experiments showed that molybdenum content and pouring temperature had an important influence on casting defects and machining of the casting components behaviour.

  • 120.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Effect of Molybdenum Content, Pouring Temperature and Cooling Rate on the Casting Defects of High Chromium White Cast Iron2017In: TMS 2017 146TH ANNUAL MEETING & EXHIBITION SUPPLEMENTAL PROCEEDINGS, Springer, 2017, p. 475-482Conference paper (Refereed)
    Abstract [en]

    High chromium white cast are commonly used in application requiring excellent abrasion resistance, as central parts for pumps. The specifications and requirements applied for the white cast iron components are among the most stringent used within the iron foundry branch. One of the biggest problems for the production of these components is hot tearing. Irrespective of the name, this phenomenon represents the formation of an irreversible failure (crack) in the still semisolid casting. This paper aims to investigate the effect of molybdenum content, pouring temperature and cooling rate on the casting defect hot tearing. The procedure to achieve this was to study one casting component, impeller, in a production scale. The experiments showed that molybdenum content and pouring temperature had an important influence on casting defects. It was also observed that the solidification rate has a strong effect on the hot cracking.

  • 121.
    Dugic, Izudin
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Inoculation of Grey Cast Iron and the Influence on Metal Expansion Penetration2011In: Proceedings book of the 11th International foundrymen conference Foundry Industry – Significance and Future Challenges / [ed] Unkić, Faruk, Croatia: University of Zagreb , 2011, , p. 12p. 378-389Conference paper (Refereed)
    Abstract [en]

    One of the most important factors which influence the microstructure evolution of cast iron is nucleation. Nucleation of eutectic phase in grey cast is assumed to take place heterogeneously. Inoculation is the most common method to influence the heterogeneous nucleation. The choice of inoculants used in grey cast iron production today is probably one of the most important parameters to obtain good quality of castings component. In some grey cast iron components which are cast in sand moulds, the metal some time penetrates into the mould producing surface defects and causes difficulties when cleaning the components. 

    The present work utilizes the latest development of primary austenite inoculation in combination with classic eutectic inoculation to limit the metallurgical contribution to metal expansion penetration. A solid shell containing the primary austenite dendrite network constitutes the barrier between the liquid metal and mould interface. Inoculants of both the primary- and eutectic phase control the permeability of the dendrite network

  • 122.
    Dugic, Izudin
    Linköping University.
    Metal Expansion Penetration During Solidification of Grey Cast Iron1999Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The meta! expansion penetration has been examined experimentally. The whole casting process was simulated using a commercial software, in order to investigate the solidification characteristics and the pore formation in the casting studied. In order to do this, a special module for cast iron was used, where nucleation and growth of all relevant phases are considered. During simulation it is possible to detect the areas where porosities are likely to be formed. The results of the experiments show that expansion penetration generally occurs in the same areas as detected in the simulation depending on the solidification path. The inoculation and solidification behaviour will result in an excess or deficiency of meta! at the end of solidification. This will lead to either meta! penetration or the formation of pores.

    A series of test castings were produced at a foundry. They were used to study the influence of chemical composition, the type and amount of inoculant and the casting temperature. The results show that the carbon and phosphorus content had an influence on meta! penetration. The tendency for meta! penetration decreased whit decreasing carbon content as well as with increasing phosphorus content.

    The experiments show that the type and amount of inoculant and casting temperature for grey cast iron influence the meta! expansion penetration in areas with late solidification and where the melt is in contact with the sand mould. The worst cases of meta! penetration were obtained with uninoculated melt. A !arge number of small eutectic cells making up a !arge fraction of the volume were observed, resulting in a !arge penetration.

  • 123.
    Dugic, Izudin
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Metal Expansion Penetration on Concave Casting Surfaces of Cylinder Heads Cast in Grey Cast Iron2009Conference paper (Refereed)
    Abstract [en]

    Cylinder heads have an extremely complex shape with large areas of concave casting surfaces. The concave casting surfaces are often associated with metal expansion penetration problems or other surface defects, e. g. surface shrinkage. The defects cause high production costs due to component rejection and increased fettling time. This report presents an investigation of the microstructure in grey cast iron close to the sand-metal interface affected by metal penetration in a complex shaped casting. The dominant penetration defect observed in the cylinder heads was expansion penetration. Even pre-solidification penetration and sand crack defects were observed. The microstructure found in the non penetrated areas is typical for solidification of grey iron cast in sand moulds.

  • 124.
    Dugic, Izudin
    Linköping University.
    The mechanisms of metal expansion penetration during solidification of grey cast iron2006Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The production of high quality castings requires the casting surface to be clean and free from defects. One type of defect often found is caused by metal penetration into the sand mould. Metal penetration is a casting surface condition resulting from either physical, mechanical and/or thermochemical reactions or a combination of these at the mould–metal interface. The metal penetrates into the voids between the sand grains to various depths without displacing the grains, thus yielding a phase of sand grains surrounded by metal and frequently by mould-metal reaction products. The present work is devoted to investigating the mechanisms of metal expansion penetration during solidification of grey cast iron.

    The phenomenon of metal expansion penetration has been examined experimentally. A series of test castings were produced at two foundries, to study the influence of chemical composition, the casting temperature and the addition of inoculants with respect to both primary and eutectic phases.

    The experiments show that the type and amount of inoculant, the casting temperature and the chemical composition influence the metal expansion penetration.

    Two major types of metal expansion penetration mechanisms are suggested with respect to the nucleation and growth of the primary and eutectic phases. The expansion penetration mechanisms found in the experimental work were also identified on complex shaped industrial castings such as clutch components and cylinder heads.

    The entire casting process was simulated using commercial software, and in which nucleation and growth of all relevant phases was considered in order to investigate the solidification characteristics and porosity formation in the casting. A good correlation between the simulation and experiments on real castings was found.

    Density and volume change in grey cast iron seem to play a decisive roll in the occurrence of metal expansion penetration. Laboratory measurements of density variations are difficult. A novel method of modeling the density variation in cast iron has been introduced.

  • 125.
    Dugic, Izudin
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    White Cast Iron for the Impellers2014In: Conference Proceedings of the 54th International Foundry Conference Portorož 2014 / [ed] Križman, A. ; Debelak, M, Ljubljana: Društvo livarjev Slovenije , 2014, , p. 8p. 71-72Conference paper (Other academic)
    Abstract [en]

    High chromium white cast iron are commonly used in applications requiring excellent abrasion resistance, as central parts for pumps. Their excellent abrasion resistance is mainly due to their solidification microstructures. The specifications and requirements applied for the white cast iron components are among the most stringent used within the iron foundry branch. One of the problems for the production of these components can be cracks. Because of this reason there are just a few iron foundries in Sweden that are able to cast the required high quality white cast iron components.

    This work has been carried out on a foundry where an impeller for pumps has been analyzed. The project work has focused on reducing cracks on casting component in a production scale using different type of shell moulding sand. The experiments showed that the shell moulding sand had an important influence on the cracks

  • 126.
    Dugic, Izudin
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Diozegi, A
    Svensson, I. L.
    Metal Expansion Penetration on Concave Casting Surfaces of Grey Cast Iron Cylinder Heads2010In: International Foundry Research/Giessereiforschung, ISSN 0046-5933, Vol. 62, no 1, p. 38-23Article in journal (Other academic)
    Abstract [en]

    Cylinder heads have an extremely complex shape withlarge areas of concave casting surfaces. The concavecasting surfaces are often associated with metalexpansion penetration problems or other surfacedefects, e. g. surface shrinkage. The defects cause highproduction costs due to component rejection andincreased fettling time. This report presents aninvestigation of the microstructure in grey cast ironclose to the sand-metal interface affected bymetal penetration in a complex shaped casting.The dominant penetration defect observedin the cylinder heads was expansion penetration.Even pre-solidification penetration and sandcrack defects were observed. The microstructurefound in the non penetrated areas is typicalfor solidification of grey iron cast in sand moulds.

  • 127.
    Dugic, Izudin
    et al.
    Jönköping University.
    Diozegi, A
    Jönköping University.
    Svensson, Ingvar L.
    Metal Expansion Penetration on Concave Casting Surfaces of Grey Cast Iron Cylinder Heads2010In: International Foundry Research/Giessereiforschung, ISSN 0046-5933, Vol. 62, no 1, p. 38-23Article in journal (Other academic)
    Abstract [en]

    Cylinder heads have an extremely complex shape withlarge areas of concave casting surfaces. The concavecasting surfaces are often associated with metalexpansion penetration problems or other surfacedefects, e. g. surface shrinkage. The defects cause highproduction costs due to component rejection andincreased fettling time. This report presents aninvestigation of the microstructure in grey cast ironclose to the sand-metal interface affected bymetal penetration in a complex shaped casting.The dominant penetration defect observedin the cylinder heads was expansion penetration.Even pre-solidification penetration and sandcrack defects were observed. The microstructurefound in the non penetrated areas is typicalfor solidification of grey iron cast in sand moulds.

  • 128.
    Dugic, Izudin
    et al.
    Jönköping University.
    Diószegi, Attila
    Jönköping University.
    Svensson, Ingvar L.
    Jönköping University.
    The Influence of Inoculation on the Metal Expansion Penetration With Respect to the Primary and Eutectic Solidification2005Report (Other academic)
    Abstract [en]

    The mechanism of metal expansion penetration of grey cast iron components is dependent on both solidification anomalies at the metal – mould interface and the inclination of the sand mould to permit the metal liquid to penetrate between the sand grains. The present work utilizes the latest development of primary austenite inoculation in combination with classic eutectic inoculation to limit the metallurgical contribution to metal expansion penetration. A solid shell containing the primary austenite dendrite network constitutes the barrier between the liquid metal and mould interface. Inoculants of both the primaryand eutectic phase control the permeability of the dendrite network.

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  • 129.
    Dugic, Izudin
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Henriksson, Felix
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Strebel, Conrad
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Kosmaz, Ozkan
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Seifeddine, Salem
    Jönköping University.
    On the Effects of Alloying Element Range on the Mechanical Properties of Recycled Aluminium Alloy EN AB-460002016In: Light Metals 2016 / [ed] Edward Williams, John Wiley & Sons, 2016Conference paper (Refereed)
    Abstract [en]

    Aluminium can be produced from the raw material bauxite or by recycling aluminium scrap. When aluminium is being recycled, the material strength is then depending on the alloying and trace elements in the aluminium scrap. This paper aims to investigate the sole effect of the alloying element range of Si, Cu, Mg, Mn and Fe on the mechanical properties of the recycled aluminium alloy EN AB-46000 by producing directional solidified samples with low defect levels.

  • 130.
    Dugic, Izudin
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Karlsson, Christian
    Älmhults Foundry AB.
    GIFA 2011 – New opportunities2011In: Swedish Foundry Technical Association Conference, Nyköping, Sweden, 2011Conference paper (Other (popular science, discussion, etc.))
  • 131.
    Dugic, Izudin
    et al.
    Jönköping University.
    Svensson, Ingvar L
    Jönköping University.
    An investigation of the effect of inoculants on the metal expansion penetration in grey iron1999In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 11, no 5, p. 333-338Article in journal (Refereed)
    Abstract [en]

    The production of quality castings requires the casting surface to be clean and free fromdefects. In some grey cast iron components which are cast in sand moulds, the metalsometimes penetrates into the mould, producing difficulties in cleaning the components. Thedefect causes very high costs due to component rejection and increased fettling in the castingindustry. Most of the grey iron foundries around the world have problems with metalpenetration on applicable components.In this work the problem of metal penetration has been studied using a commercial castingcomponent. Eight castings were mounted on the pattern plate and five different inoculantswere investigated. The experiments show that the inoculation of grey cast iron will influencethe metal penetration in areas with late solidification times and where the melt is in contactwith the sand mould. In all experiments 0.14 % inoculant was added in the pouring ladle.The experiments show that the best results to reduce metal penetration have been obtainedwhen using the inoculant which contained silicon, aluminium and zirconium. Using thisinoculant, the average penetration area was only about 20 % of what was found using theworst inoculant. However, this inoculant also gave rise to a large tendency to formation sinks.The experiments also show two main classes of eutectic cell size. One class nucleated at thebeginning of the eutectic solidification and one at the end of the solidification.Two other inoculants, both containing Al and Si have about the same base composition. Fromthe measurements of penetration areas, one can draw the conclusion that the inoculant withthe smallest grain size gives nuclei with the shortest lifetime. The coarser grains give a longerdissolution time and this promotes the survival of the nuclei. At the end of solidification, a larger amount of graphite will precipitate at higher temperatures if new nuclei can beactivated. If the hot spot is located close to the metal surface, the metal will expand into themould; resulting in metal expansion penetration.The worst cases of metal penetration have been obtained using an inoculant containingtitanium. A large number of small eutectic cells and high volume of the small cells wereobserved, which leads to severe penetration.

  • 132.
    Dugic, Izudin
    et al.
    Högskolan i Jönköping.
    Svensson, Ingvar L
    Högskolan i Jönköping, JTH. Forskningsområde Material och tillverkning - gjutning.
    An investigation of the effect of inoculants on the metal expansionpenetration in grey iron1998Report (Other academic)
  • 133.
    Dugic, Izudin
    et al.
    Jönköping University.
    Svensson, Ingvar L
    Jönköping University.
    The effect of chemical composition on the metal expansion penetration in grey cast iron1999Report (Other academic)
    Abstract [en]

    In some grey cast iron components which are cast in sand moulds, the metal sometimes penetrates into the mould producing defects and causing difficulties when cleaning the components. To improve knowledge of the metal penetration mechanism a series of test castings was performed at ITT Flygt’s foundry where the influence of chemical composition was studied. The chemical composition of the melt was changed in the ladle before pouring. The result showed that the carbon and phosphorus content had an influence on metal penetration. The metal penetration tendency decreased when decreasing the carbon content as well as when increasing the phosphorus content. The penetration areas were analysed in a Scanning Electron Microscope (SEM) with Energy Dispersive Analysis (EDS). The analysis showed that the average chemical composition in the penetration zones was close to the initial composition of the alloy. Consequently, no significant macro segregation of carbon or phosphorous could be observed. The whole casting process was simulated with the software MAGMAsoftTM, in order to investigate the solidification characteristics as well as the porosity formation in the casting studied. For this, a special module for cast iron was used, MAGMAironTM, where nucleation and growth of all relevant phases are considered. During simulation it is possible to detect the areas where porosities are likely to be formed. The results show that expansion penetration generally occurs in the same areas depending on the mode of solidification. The inoculation and solidification behaviour will result in excess or deficiency of the metal at the end of solidification, which will lead to either metal penetration or formation of porosities.

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  • 134.
    Efthimiopoulos, I.
    et al.
    Natl Hellen Res Fdn, Greece;Deutsch GeoForschungsZentrum GFZ, Germany.
    Palles, D.
    Natl Hellen Res Fdn, Greece.
    Richter, S.
    Friedrich Schiller Univ Jena, Germany;TRUMPF Lasertech GmbH, Germany.
    Hoppe, U.
    Univ Rostock, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Wondraczek, L.
    Friedrich Schiller Univ Jena, Germany;Fraunhofer Inst Appl Opt & Precis Engn, Germany.
    Nolte, S.
    Friedrich Schiller Univ Jena, Germany;Fraunhofer Inst Appl Opt & Precis Engn, Germany.
    Kamitsos, E. I.
    Natl Hellen Res Fdn, Greece.
    Femtosecond laser-induced transformations in ultra-low expansion glass: Microstructure and local density variations by vibrational spectroscopy2018In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 123, no 23, article id 233105Article in journal (Refereed)
    Abstract [en]

    We report X-ray diffraction, resonance Raman, and infrared (IR) results on pristine ultra-low expansion (ULE) glass, a binary titanosilicate glass with 5.67 mol. % TiO2. ULE processing by femtosecond (fs) laser radiation leads to nanograting writing and photo-darkening for imaging and data storage. We investigate here the vibrational/structural changes induced by fs laser irradiation of ULE at 515 nm. Optical imaging revealed the formation of micro-cavities, and Raman mapping showed molecular oxygen trapped in such cavities of laser-irradiated ULE glass. While titanium in the pristine glass was found predominantly in tetrahedral Ti4+ sites highly dispersed in the silicate matrix, Raman and IR reflectance spectroscopy on laser-irradiated ULE indicated the formation of Ti3+ sites; Ti3+ octahedral sites are formed in the shells of cavities and aggregate in amorphous Ti2O3-type clusters, while the glass around and below cavities contains Ti3+ tetrahedral sites dispersed in the silicate network. Laser-processed ULE glass was found to also exhibit local restructuring of the silicate matrix. Shifts of the strong IR band at about 1080-1100 cm(-1) were translated into changes of the average Si-O-Si bond angle in the laser-transformed areas and found to reflect local density variations; the average local density increases relative to silica glass up to about 8% in the shells of micro-cavities and decreases by about 0.5% in the surrounding material. Chemical processes were proposed to account for photo-darkening and the local structural transformation effect in the probed areas of the fs laser-processed ULE glasses. Published by AIP Publishing.

  • 135.
    Egüz, Izzettin Osman
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Hydraulic press construction for fitting the bearings to the housing2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report was written as a result of a Bachelor Degree Project, together with Swepart Transmission AB. The report contains the construction of a hydraulic press for the assembly operation.

    The project started with a new construction of a hydraulic press for the bearings’ assembly. The goal within the thesis work was to fit the three bearings to the housing by only one press motion. This operation should be very safety because of the sensitive tolerance at the bearings and housing. Construction of the cylinders, rams and bolster were the most important parts at this project because this parts’ functions are very important for this assembly.

    The next step of this thesis was to calculate the hydraulic press components’ parameters and then choose the suitable components. The focus was to choose more useful and reliable components.

    The hydraulic press was modeled in the CAD program Solid Works and 2D technical drawing was drawn in the Autocad. The frame material was chosen and the frame was analysised in the Solid Works.

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  • 136.
    Ehlers, Sören
    et al.
    Ship Laboratory, Helsinki University of Technology.
    Enquist, Bertil
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Uniaxial tensile of steel dog-bone specimens2007Report (Other academic)
    Abstract [en]

    This test report describes the test arrangement and the results of 4 sets of tensile specimens tested under uniaxial tension. The Aramis 4M optical strain measuring system was used to study the necking phenomena. Strain histories for a large area of the specimen over the entire range of the test are obtained and presented. The manufactures given yield strengths were 235 MPa and 275 MPa, for the nominal thickness's of 4 mm and 6 mm respectively. The specimen dimensions were according to classification society's standards and of non standard geometry. The usage of optical strain measuring system entails very satisfactory information of the whole testing process, respectively the deformation distribution. This report shall serve as a basis reference for future research in the field of metal deformation analysis. True stress versus strain curves can be derived accurately and a comparison between the clamping displacement versus Aramis displacement at a certain point can be made based on the presented results.

  • 137.
    Eitelberger, Johannes
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    de Borst, Karin
    Vienna University of Technology, Austria.
    Jäger, Andreas
    Vienna University of Technology, Austria.
    Multiscale prediction of viscoelastic properties of softwood under constant climatic conditions2012In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 55, p. 303-312Article in journal (Refereed)
    Abstract [en]

    This paper covers the development and validation of a multiscale homogenization model for linear viscoelastic properties of wood. Starting point is the intrinsic structural hierarchy of wood, which is accounted for by several homogenization steps. Using the correspondence principle, an existing homogenization model for the prediction of elastic properties of wood is adapted herein for upscaling of viscoelastic characteristics. Accordingly, self-consistent, Mori–Tanaka, and unit-cell-based techniques are employed, leading to pointwise defined tensorial creep and relaxation functions in the Laplace-Carson domain. Subsequently, these functions are back-transformed into the time domain by means of the Gaver-Stehfest algorithm. With this procedure the orthotropic macroscopic creep behavior of wood can be derived from the isotropic shear behavior of the lignin-hemicellulose phase. A comparison of model predictions for viscoelastic properties of softwood with corresponding experimentally derived values yields very promising results and confirms the suitability of the model.

  • 138.
    Ekevid, Torbjörn
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design. Maskinteknik.
    Lane, Håkan
    Wiberg, Nils-Erik
    Adaptive solid wave propagation: Influences of boundary conditions in high-speed train applications2006In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, Vol. 195, no 4-6, p. 236-250Article in journal (Refereed)
    Abstract [en]

    Wave propagation in solid materials is of great interest in many engineering applications. The fact that the area of interest changes with time creates a number of computational problems such as the need for a mesh density varying in space and time. This means that the mesh must be continuously updated and controlled, rendering a large demand of computer effort. In certain applications like railway mechanics there are mobile loads. A load speed close to the natural speed in the underlying soil causes specific problems, shock waves being one of them. The transmitted waves have to leave the defined finite element domain without reflection, which imposes a need for certain modelling methods. The paper will deal with quality controlled FE-procedures for wave propagation including error estimation and mesh refinement/coarsening. As an application an important problem from railway mechanics is considered. When a high-speed train approaches an area with decreasing thickness of underlying soft soil on a stiff rock it is expected that the reflection of the wave will increase the total amplitude of the wave. We will study this problem with the procedures described above in full 3D with partly absorbing boundaries

  • 139.
    Ekstrand, Johan
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Enhancement of Phenol Formaldehyde Adhesive with Crystalline Nano Cellulose2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    The wood industries to this day use almost exclusively petroleum derived adhesives that are based mainly on the reaction of formaldehyde with urea, melamine or phenol. These adhesives have low cost and good adjustable properties which makes it hard for bio-based alternatives to compete. Phenol formaldehyde (PF), as an example of a synthetic adhesive, has been in use for over 100 years. In some parts of the world, legislation around formaldehyde is changing, and there is an increasingly voluntary awareness about the toxicity and unsustainability of formaldehyde. Industries realize that raw materials from oil is unstainable. The latter is currently a driving factor behind research on alternatives to amino based adhesives. Also, consumer interest in healthy and sustainable products, such as emitting less formaldehyde indoors, increases the need for bio based adhesives.

    Cellulose contained in plant cell walls is a renewable, abundant and nontoxic resource. During the last decades, many innovations have been achieved around cellulose and this trend does not seem to be slowing down. Cellulose shows excellent mechanical properties, high strength, high elastic modulus as well as having a low density.

    Research about cellulose reinforced adhesives has been increased the last years. This thesis studied the enhancement of phenol formaldehyde adhesive with Crystalline Nano Cellulose (CNC) at 5wt% and 10wt% loading levels for producing plywood boards. Indecisive results when using CNC higher than 3wt%, especially with PF resin, have been reported by other authors.

    In this thesis, European standards were applied. EN 314 was applied to test the panels shear strength. Three (3) treatment classes were selected, indoor room condition as well as pre-treatments 5.1.1 and 5.1.3. Other properties measured were modulus of elasticity, thickness swelling, formaldehyde emissions.

    Results showed a shear strength increase for all pre-treatment classes. 10wt% CNC mixture with phenol formaldehyde in water bath, pre-treatment (5.1.1) for 24h showed the highest increase in shear strength (+73,9%). The 10 wt% CNC mixture panels also showed the highest wood fibre failure of all panel types produced. A decrease in MOE has been observed with 10 wt% CNC compared to the 5 wt% CNC panels. Formaldehyde emissions tests were inconclusive, but since less PF was used, there was a general reduction in emissions. The 5 wt% CNC panels were superior in terms of modulus of elasticity and swelling and also showed improved shear strength. 

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  • 140.
    Eliasson, Lars
    University of Kalmar, Department of Technology.
    Significance of raw material quality for finger jointing of knot freeboards2008In: END USER’S NEEDS FOR WOOD MATERIAL AND PRODUCTS / [ed] . Gard, W.F. & van de Kuilen, J.W.G., 2008, p. 41-50Conference paper (Refereed)
  • 141.
    Elmukashf, Elsiddig
    et al.
    Royal Institute of Technology, (KTH).
    Kroon, Martin
    Royal Institute of Technology, (KTH).
    Numerical analysis of dynamic crack propagation in rubber2012In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 177, no 2, p. 163-178Article in journal (Refereed)
    Abstract [en]

    In the present paper, dynamic crack propagation in rubber is analyzed numerically using the finite element method. The problem of a suddenly initiated crack at the center of stretched sheet is studied under plane stress conditions. A nonlinear finite element analysis using implicit time integration scheme is used. The bulk material behavior is described by finite-viscoelasticity theory and the fracture separation process is characterized using a cohesive zone model with a bilinear traction-separation law. Hence, the numerical model is able to model and predict the different contributions to the fracture toughness, i.e. the surface energy, viscoelastic dissipation, and inertia effects. The separation work per unit area and the strength of the cohesive zone have been parameterized, and their influence on the separation process has been investigated. A steadily propagating crack is obtained and the corresponding crack tip position and velocity history as well as the steady crack propagation velocity are evaluated and compared with experimental data. A minimum threshold stretch of 3.0 is required for crack propagation. The numerical model is able to predict the dynamic crack growth. It appears that the strength and the surface energy vary with the crack speed. Finally, the maximum principal stretch and stress distribution around steadily propagation crack tip suggest that crystallization and cavity formation may take place.

  • 142.
    Elmukashfi, Elsiddig
    et al.
    Royal Institute of Technology, (KTH).
    Kroon, Martin
    Royal Institute of Technology, (KTH).
    Numerical analysis of dynamic crack propagation in biaxially strained rubber sheets2014In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 124/125, p. 1-17Article in journal (Refereed)
    Abstract [en]

    This paper proposes a computational framework for dynamic crack propagation in rubber in which a nonlinear finite element analysis using cohesive zone modeling approach is used. A suddenly initiated crack at the center of biaxially stretched sheet problem is studied under plane stress conditions. A transient dynamic analysis using implicit time integration scheme is performed. In the constitutive modeling, the continuum is characterized by finite-viscoelasticity theory and coupled with the fracture processes using a cohesive zone model. This computational framework was introduced previously by the present authors (Elmukashfi and Kroon, 2012). In the current work, the use of a rate-dependent cohesive model is examined in addition to investigation of generalized biaxial loading cases. A Kelvin–Voigt element is used to describe the rate-dependent cohesive model wherein the spring is described by a bilinear law and dashpot with a constant viscosity is adopted. An explicit integration is used to incorporate the rate-dependent cohesive model in the finite element environment. A parametric study over the cohesive viscosity is performed and the steady crack propagation velocity is evaluated and compared with experimental data. It appears that the viscosity varies with the crack speed. Further, the total work of fracture is estimated using rate-independent cohesive law such that the strength of the cohesive zone is assumed to be constant and the separation work per unit area is determined form the experimental data. The results show that fracture-related processes, i.e. creation of new surfaces, cavitation and crystallization; contribute to the total work of fracture in a contradictory manner.

  • 143.
    Engström, Christian
    et al.
    Umeå university, Sweden.
    Torshage, Axel
    Universität Bern, Switzerland.
    Spectral properties of conservative, dispersive, and absorptive photonic crystals2018In: GAMM - Mitteilungen, ISSN 0936-7195, Vol. 41, p. 1-16, article id e201800009Article in journal (Refereed)
    Abstract [en]

    This article reviews both recent progress on the mathematics of dispersive and absorptive photonic crystals and well-established results on conservative photonic crystals. The focus is on properties of the photonic band structures and we also provide results that are of importance for the understanding of lossy metal-dielectric photonic crystals.

  • 144.
    Ericsson, Mikael
    et al.
    Högskolan Väst, Sweden.
    Bolmsjö, Gunnar
    University West, Sweden.
    Nylén, Per
    Högskolan Väst, Sweden.
    Three-dimensional simulation of robot path and heat transfer of a TIG-welded part with complex geometry2002In: 11th International Conferences on Computer Technology in Welding: Colombus, Ohio December 6-7, 2001, Society of Manufacturing Engineers, North American Manufacturing Research Institution, 2002, p. 309-316Conference paper (Other academic)
    Abstract [en]

    The application of commercial software (OLP) packages for robot simulation, and programming, use interactive computer graphics, provide powerful tools for creating welding paths off-line. By the use of such software, problems of robot reach, accessibility, collision and timing can be eliminated during the planning stage. This paper describes how such software can be integrated with a numerical model that predicts temperature-time histories in the solid material. The objective of this integration is to develop a tool for the engineer where robot trajectories and process parameters can be optimized on parts with complex geometry. Such a tool would decrease the number of weld trials, increase productivity and reduce costs. Assumptions and principles behind the modeling techniques are presented together with experimental evaluation of the correlation between modeled and measured temperatures.

  • 145. Eriksson, Jerry
    et al.
    Ludvigsson, Mikael
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Serrano, Erik
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Enquist, Bertil
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Load bearing timber glass composites: A WoodWisdom-Netproject for innovative building system2013In: COST Action TU0905 Mid-term Conference on Structural Glass / [ed] Jan Belis; Christian Louter; Danijel Mocibob, Boca Raton, Fla: CRC Press, 2013Conference paper (Refereed)
    Abstract [en]

    The aim of this three year project, which is part of the WoodWisdom-Net researchprogram, is to develop an innovative load bearing building system composed of timberglasscomposites. The structural loads applied onto these composites will be transferred to, andsupported by, the glass component, in contrary to today’s traditional solutions where glass elementsonly function as an environmental shield. Using such structural elements will make itpossible to largely increase the glass surface in buildings, allowing the presence of more naturallight in personal homes and office buildings.

    Timber-glass shear walls and beams will be developed taking into consideration long-term behaviorand seismic performance. Design concepts, feasibility studies and performance assessmentsof these components will be performed in order to improve the overall performance. Theproject also includes the development of new design calculations as well as the optimization ofmanufacturing methods.

    Material properties of timber, glass and adhesives will be determined from small and large scaleexperimental investigations, and will be used as input for theoretical calculations and modelingwork. The projects industrial partners will function as expertise and take part in the developmentand construction of demonstration objects.

    The project consortium is composed of academic and industrial partners from Austria, Sweden,Germany, Turkey, Slovenia, Chile, and Brazil. This paper presents material specifications andresults from small scale testing performed by the Swedish project partners.

  • 146.
    Fallqvist, B.
    et al.
    Royal Institute of Technology, (KTH).
    Kroon, Martin
    Royal Institute of Technology, (KTH).
    Constitutive modelling of composite biopolymer networks2016In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 395, p. 51-61Article in journal (Refereed)
    Abstract [en]

    The mechanical behaviour of biopolymer networks is to a large extent determined at a microstructural level where the characteristics of individual filaments and the interactions between them determine the response at a macroscopic level. Phenomena such as viscoelasticity and strain-hardening followed by strain-softening are observed experimentally in these networks, often due to microstructural changes (such as filament sliding, rupture and cross-link debonding). Further, composite structures can also be formed with vastly different mechanical properties as compared to the individual networks. In this present paper, we present a constitutive model presented in a continuum framework aimed at capturing these effects. Special care is taken to formulate thermodynamically consistent evolution laws for dissipative effects. This model, incorporating possible anisotropic network properties, is based on a strain energy function, split into an isochoric and a volumetric part. Generalisation to three dimensions is performed by numerical integration over the unit sphere. Model predictions indicate that the constitutive model is well able to predict the elastic and viscoelastic response of biological networks, and to an extent also composite structures.

  • 147.
    Forde, Sean
    et al.
    National University of Ireland, Ireland.
    Hynes, Michael
    National University of Ireland, Ireland.
    Jonson, Bo
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Dissolution of glass compositions containing no added lead in simulated lung fluid2008In: International journal of hygiene and environmental health (Print), ISSN 1438-4639, E-ISSN 1618-131X, Vol. 211, no 3-4, p. 357-366Article in journal (Refereed)
    Abstract [en]

    Six crystal glass compositions containing no added lead were studied with respect to the potential exposure of workers during the cold end working of crystal type glasses. During cutting and grinding of crystal glass, fine dusts are produced. These may be inhaled by the workers with subsequent partial dissolution of the dusts in the lung fluid. In order to provide a measure of the degree of dissolution in the case of the six crystal glass compositions produced in this work the release of antimony, barium, silicon, and bismuth was investigated by passing simulated lung fluid over powdered samples of the crystal compositions having a diameter of ca. 0.5 micron for a period of 21 days. The results show that it is possible to produce durable glass containing no added lead. While the leaching and weathering of the glass compositions studied here could be correlated with the mole ratio of alkali/silica and the degree of depolymerisation of the silica network, the dissolution of silica in simulated lung fluid seems to be independent of this property.

  • 148.
    Foti, Dafni
    et al.
    Aristotle Univ Thessaloniki, Greece.
    Adamopoulos, Stergios
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Voulgaridou, Eleni
    Aristotle Univ Thessaloniki, Greece.
    Voulgaridis, Elias
    Aristotle Univ Thessaloniki, Greece.
    Passialis, Costas
    Aristotle Univ Thessaloniki, Greece.
    Amiandamhen, Stephen
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Daniel, Geoffrey
    Swedish University of Agricultural Sciences, Sweden.
    Microstructure and compressive strength of gypsum-bonded composites with papers, paperboards and Tetra Pak recycled materials2019In: Journal of Wood Science, ISSN 1435-0211, E-ISSN 1611-4663, Vol. 65, no 1, p. 1-8, article id 42Article in journal (Refereed)
    Abstract [en]

    The incorporation of recycled papers, paperboards and Tetra Pak as filling materials in brittle matrices presents aninteresting approach in the utilization of waste materials for building construction. This paper examines the compressivestrength and microstructure of gypsum-bonded wastepaper-based composites. Recycled wastepaper of varioustypes (office paper, magazine paper and newspaper), cardboards, paper boxes and Tetra Pak were shredded to shortlength strips of about 4 × 18 mm. The shredded materials were used as filling materials in natural gypsum in a ratioof 1:3 (v/v), and water was added to the mix. The paste was formed in cylindrical samples measuring 10 cm in lengthand 5 cm in diameter. Seven different types of composites were produced depending on the material used. Thecomposite products with newspaper and magazine paper had significantly lower density and compressive strength(p < 0.05) than the others. However, the differences were small to have any practical importance. The density valuesranged between 1.26 and 1.34 g/cm3, and compressive strength was the lowest (4.48 N/mm2) in the gypsum–magazinepaper composites and the highest (6.46 N/mm2) in the gypsum–Tetra Pak I composites. Since the samplesproduced in this study exhibited adequate compressive strength, the products could be suitable for such applicationsas interior walls in building constructions. Scanning electron microscopy (SEM) examination of the fractured surfacesrevealed needle-like structures of gypsite crystals surrounding the fibers, which indicates good adhesion between thehydrophobic matrix and lignocellulosic fibers.

  • 149.
    Fredriksson, Thomas
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    En metod för klassificering av miljön för transformatorstationer2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 150.
    Füssl, Josef
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    Computational Mechanics for Advanced Timber Engineering: from material modeling to structural applications2012In: IACM Expressions, no 32, p. 6-11Article in journal (Other academic)
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