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  • 1.
    Alzghoul, Ahmad
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Karlberg, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Data stream mining for increased functional product availability awareness2011In: Functional Thinking for Value Creation: Proceedings of the 3rd CIRP International Conference on Industrial Product Service Systems, Technische Universität Braunschweig, Braunschweig, Germany, May 5th - 6th, 2011 / [ed] Jürgen Hesselbach; Christoph Herrmann, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2011, p. 237-241Conference paper (Refereed)
    Abstract [en]

    Functional Products (FP) and Product Service Systems (PSS) may be seen as integrated systems comprising hardware and support services. For such offerings, availability is key. Little research has been done on integrating Data Stream Management Systems (DSMS) for monitoring (parts of) a FP to improve system availability. This paper introduces an approach for how data stream mining may be applied to monitor hardware being part of a Functional Product. The result shows that DSMS have the potential to significantly support continuous availability awareness of industrial systems, especially important when the supplier is to supply a function with certain availability.

  • 2. Andersson, Börje
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Thermal stresses in large butt-welded plates1981In: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 4, no 3-4, p. 491-500Article in journal (Refereed)
    Abstract [en]

    In shipyard panel-production lines several rectangular plates ae butt welded to form large panels. One problem is the tendency of hot cracking in the end portion of the butt weld. In this paper transient temperature fields and stress fields in butt-welded plates are calculated using the finite-element method. The calculations are performed for different welding speeds, for different heat inputs, and for one-sided and two-sided welding.

  • 3.
    Asplund, Christer
    et al.
    Luleå tekniska universitet.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    MacPherson strut wheel suspension dynamics1989Report (Other academic)
  • 4. Drugge, Lars
    et al.
    Stensson, Annika
    Luleå tekniska universitet.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    A theoretical and experimental study on the dynamic behaviour of a catenary system1997In: Theoretical and applied mechanics 1996: proceedings of the XIXth International Congress of Theoretical and Applied Mechanics, Kyoto, Japan, 25 - 31 August 1996 / [International Union of Theoretical and Applied Mechanics] / [ed] Tomomasa Tatsumi, Amsterdam: Elsevier, 1997Conference paper (Refereed)
  • 5. Goldak, J.
    et al.
    Gu, M.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Numerical aspects of modelling welds1993In: ASM handbook: Welding, brazing and soldering, Materials Park: ASM International, 1993, p. 1131-1140Chapter in book (Other academic)
  • 6.
    Goldak, John
    et al.
    Carleton University, Ottawa.
    Asadi, Mahyar
    Carleton University, Ottawa.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Numerical aspects of modeling welds2011In: ASM Handbook, ASME Press, 2011, p. 819-829Chapter in book (Refereed)
  • 7.
    Gustafsson, Göran
    et al.
    Luleå tekniska universitet.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    On the calculation of head impact motion using experimental data1981In: Proceedings: VIth. International IRCOBI Conference on the Biomechanics of Impacts : 8., 9., 10. September 1981, Salon de Provence (France), Bron, 1981, p. 225-234Conference paper (Refereed)
    Abstract [en]

    Numerous head impact tests have been carried out by the Biomechanics department of the Highway Safety Research Institute, University of Michigan, Ann Arbor, during the past few years. The purpose of this work is to investigate the head motion during impact loading (the unloading phase is not considered) and especially to determine if the head slips on the impactor or rotates around it. Data from three different types of tests have been analyzed: Front, side and rear impacts on human heads. The data consists of linear and angular accelerations and velocities for the head (considered as a rigid body). These four quantities are some of the most common that have been suggested as primary causes of injury. By using experimental data the position of the instantaneous point of rotation was determined as a function of time during impact loading. It was found that slip occurs between the impactor and the head with very few exceptions. It was also found that the human skull performs plane motion after front or rear impact. This is probably due to the symmetry around the midsagittal plane. In side impact on the human skull it was found that the motion is three-dimensional.

  • 8.
    Jeppsson, Peter
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Karlsson, Lennart
    Häggblad, Hans-åke
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    A concurrent engineering system with application to hot isostatic pressing1997In: Modeling in welding, hot powder forming, and casting, Materials Park, Ohio: ASM International, 1997, p. 117-128Chapter in book (Other academic)
  • 9.
    Johanson, Mathias
    et al.
    Alkit Communications AB.
    Johansson, Lars-Åke
    Alkit Communications AB.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Turning an hourglass into a diamond: inter-organizational collaborative work in the enterprise of the future2011Conference paper (Refereed)
  • 10.
    Johanson, Mathias
    et al.
    Alkit Communications AB.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    A framework for distributed collaborative automotive testing2006In: Challenges in collaborative engineering :: CCE '06 ; state of the art and future challenges in collaborative design ; proceedings of the international workshop, April 19 - 20 2006, Prague, Czech Republic, in conjunction with DDECS '06 / [ed] Leandro Soares Indrusiak, Gliwice: Interprint , 2006Conference paper (Refereed)
    Abstract [en]

    In this paper we explore the opportunities of improving the testing and verification phases of product development in the automotive industry, through a combination of broadband telematic services and tools and methods for distributed collaborative engineering. The development of a prototype system for remote vehicle testing is described, and experiences from experimental usage of the system at an automotive winter testing facility are reported. The prototype system supports real time communication of audio, video and measurement data from a vehicle at a test track, to a remote location such as an automotive company's development site. Initial results from using the system are promising, indicating a clear potential of improving the testing and verification phases of product development within the automotive sector, which will be essential in the future in order to meet demands on shortened development cycles and increased testing needs.

  • 11. Johanson, Mathias
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Risch, Tore
    Department of Information Technology, Uppsala University.
    Relaying controller area network frames over wireless internetworks for automotive testing applications2009In: 2009 4th International Conference on Systems and Networks Communications: (ICSNC 2009) ; Porto, Portugal, 20 - 25 September 2009 / [ed] Eugen Borcoci, Piscataway, NJ: IEEE Communications Society, 2009Conference paper (Refereed)
    Abstract [en]

    In this paper we describe how controller area network (CAN) frames can be relayed over a wireless Internet connection, enabling remote access to the CAN buses of vehicles for applications in automotive telematics. This opens up many new possibilities for diagnostics, monitoring, testing, analysis and verification, which we believe can significantly reduce the time required for the testing and verification phases of automotive development. A CAN-over-IP tunneling protocol is described and the design and implementation of a generic system for remote access to the CAN bus of vehicles is presented. Examples of applications of the technology are given and implications in terms of new possibilities and challenges in automotive engineering are discussed.

  • 12.
    Johanson, Mathias
    et al.
    Alkit Communications AB.
    Löfstrand, Magnus
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Collaborative innovation through distributed engineering services2009Conference paper (Refereed)
    Abstract [en]

    Rapid advancement in information and communication technology in recent decades has presented new opportunities for carrying out sophisticated engineering work in distributed teams, using tools and techniques collectively referred to as Distributed Collaborative Engineering (DCE). This kind of on-line collaboration not only cuts costs due to reduced travel, but also fosters innovation in product development, by bringing together groups of people in collaborative teams with complementary competences, that would otherwise be difficult to realize. Moreover, the convergence of technologies for telecommunication and information technology now makes it possible for companies specialized in collaboration technology to deliver sophisticated services for DCE, which can be purchased by engineering companies on a pay-per-use basis. By outsourcing the installation, management and support of the collaboration tools, the engineering companies can focus on their product development projects while harnessing the full potential of DCE to become more efficient and competitive. We believe that this new way of conducting engineering work will be an important key to innovation in the future. In this paper, we analyze the requirements for delivering DCE as a service and describe the implications this has in terms of systems design, business models and competence requirements. Furthermore, in addition to the primary return on investment in DCE services, we cite cost reductions and reduced CO2 emissions as further benefits.

  • 13. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Deformation and stresses in butt-welding of large plates1985In: Numerical methods in heat transfer: expanded and edited versions of selected papers from an international conference held in Swansea, July 1979 / [ed] R.W. Lewis; K. Morgan, John Wiley & Sons, 1985, Vol. 3, p. 35-57Conference paper (Refereed)
  • 14. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Deformations and stresses in butt-welding of large plates with special reference to the mechanical material properties1985In: Journal of engineering materials and technology, ISSN 0094-4289, E-ISSN 1528-8889, Vol. 107, no 4, p. 265-270Article in journal (Refereed)
    Abstract [en]

    Simulation of automatic butt-welding of large plates was investigated. Two different steels were considered. The plates were tack-welded before the butt-welding. The simulation includes the tack-welding, the butt-welding and the cooling to room temperature. The simulations should lead to an understanding of the mechanics behind the change in gap width in front of the moving arc, which is of importance in automatic welding production. The residual stresses due to the butt-welding were also studied. The magnitude and the distribution of the residual stress are important in design of welded structures.

  • 15. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Kan svetsegenspänningar och svetsdeformationer förutsägas?1986In: Svetsen, ISSN 0039-7091, Vol. 45, no 5, p. 6-9Article in journal (Other academic)
    Abstract [en]

    Many difficulties in welding result from the fact that heat input causes uneven heating of the welded object. This article reports on the results of an investigation carried out with the object to find out whether it is possible to predict residual stresses in welding and weld deformations with the aid of new computational methods used in continum mechanics. Butt welding of flat plates was studied in this investigation. Deformations, residual stresses, and gap width variations during the welding process were calculated.

  • 16. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Plate motion and thermal stresses in root-bead butt-welding and one-pass butt-welding of two different steels1984Conference paper (Other academic)
  • 17. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Plate motion and thermal stresses in root-bead butt-welding of plates1985In: Numerical methods in thermal problems: proceedings of the fourth international conference held in Swansea, UK on 15th - 18th July, 1985 / [ed] R.W. Lewis, Swansea: Pineridge Press , 1985, p. 1092-1102Conference paper (Refereed)
    Abstract [en]

    In this paper root-bead welding of plates of two different sizes was experimentally and theoretically analysed. The material of the plates was a fine-grain steel with yield limit 360 MPa. The finite element method was used for both the thermal analyses and the mechanical analyses. Temperature-dependent material properties and volume changes due to phase transformations were considered. Plane stress conditions were assumed. Good agreement between calculated and measured values were obtained.

  • 18. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Plate motion in butt-welding of tack-welded plates1984In: Numerical methods for transient and coupled problems: proceedings of an International Conference held in Venice, Italy on July 9th-13th, 1984 / [ed] R. W. Lewis; P. Bettess; E. Hinton; B.A. Schreffler, Swansea: Pineridge Press , 1984, p. 351-359Conference paper (Refereed)
  • 19. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Simulation of tack welding procedures in butt joint welding of plates1985In: Welding Journal, ISSN 0043-2296, Vol. 64, no 10, p. 296-301Article in journal (Refereed)
    Abstract [en]

    The influence of tack welding procedure on change in root opening was investigated. This change during the first part of welding depends on the order in which the tack welds are made. It is also affected by the starting position of the welding arc. These effects were studied in seven theoretical analyses - three cases where the tack welding procedures differed and four cases where the temperature fields at the beginning of the butt joint welding differed. The material investigated was a fine-grain steel with a yield stress of 360 MPa (52,200 psi) at room temperature. The filler material was ESAB 1. 2/12. 51 (AWS ER70S-6).

  • 20. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Thermal stresses and plate motion in butt-welding1983In: Numerical methods in thermal problems: proceedings of the third international conference, held in Seattle, USA, on 2nd - 5th August, 1983 / [ed] R.W. Lewis, Swansea: Pineridge Press , 1983, p. 270-279Conference paper (Refereed)
  • 21. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Thermal stresses, plate motion and hot-cracking in butt-welding1983In: Mechanical behaviour of materials - IV: proceedings of the fourth International conference, Stockholm, Sweden, 15-19 August 1983 / [ed] Janne Carlsson; Nils-Gunnar Ohlson, Oxford: Elsevier, 1983, p. 273-279Conference paper (Refereed)
  • 22. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindén, G.
    The influence of welding deformations on tolerance requirements in automatic butt welding1985Conference paper (Refereed)
  • 23. Jonsson, Mikael
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Sundin, Karl-Gustaf
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Experimental and numerical analysis of damped transient vibration of beam structures1989In: Proceedings of the International conference on noise and vibration: August 16-18, 1989 at Novetel Orchid Inn Singapore, Singapore: Nanyang Technological Institute , 1989, p. B.53-B.64Conference paper (Refereed)
  • 24. Josefson, B.L.
    et al.
    Jonsson, Mikael
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Karlsson, R.
    Karlsson, T.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Transient and residual stresses in a single-pass butt welded pipe1989In: Residual stresses: International conference : Papers / [ed] G. Beck; S. Denis; A. Simon, Elsevier, 1989, p. 497-503Conference paper (Refereed)
  • 25. Josefson, B.L.
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Jonsson, Mikael
    Thermo-mechanical FE-analysis of butt-welding of a Cu-Fe canister for spent nuclear fuel1993In: Structural mechanics in reactor technology: transactions of the 12th International Conference on Structural Mechanics in Reactor Technology, Stuttgart, Germany, 15-20 August 1993, Amsterdam: Elsevier, 1993Conference paper (Refereed)
  • 26. Josefsson, B. Lennart
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Häggblad, Hans-åke
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Stress redistribution and void growth in butt-welded canisters for spent nuclear fuel1993Report (Other academic)
  • 27. Josefsson, B.L.
    et al.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Häggblad, Hans-åke
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Thermo-mechanical FE-analysis of the fabrication of a Cu-Fe canister for spent nuclear fuel1995In: Transactions of the 13th International Conference on Structural Mechanics in Reactor Technology : Porto Alegre, Brazil, August 13 - 18, 1995: [conference organization by:] International Association for Structural Mechanics in Reactor Technology e.V. (IASMiRT); Universidade Federal do Rio Grande do Sul (UFRGS). / [ed] R.C Ramos de Menezes, Porto Alegre: Ed. da Univ. , 1995Conference paper (Refereed)
  • 28.
    Karlberg, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Karlsson, Martin
    Karlsson, Lennart
    Näsström, Mats
    Dynamics of rotor systems with clearance and weak pedestals in full contact2010In: 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery 2010 (ISROMAC-13): Honolulu, Hawaii, USA, 4 - 7 April 2010, Red Hook, NY: Curran Associates, Inc., 2010, p. 531-536Conference paper (Refereed)
    Abstract [en]

    Many rotating machineries are supported by bearings with clearance, which are further clamped in, compared to the bearing stiffness, weak pedestals. As have been reported in several studies, it is essential to choose a proper clearance in order to avoid unwanted vibrations. When rotating machineries supported by bearings with clearance are subjected to stationary loads (gravity, magnetic pull etc.), it may not loose contact between the shaft and the bearing (i.e. full contact). However, even in full contact unwanted dynamics can occur which is of interest in this paper. It is found that the clearance give raise to anisotropic pedestal stiffness. It is further shown that some of the resonance frequencies decrease with the clearance.

  • 29. Karlsson, Lennart
    Activity: Euromech 221, The mechanical effects of welding1987Conference paper (Other (popular science, discussion, etc.))
  • 30. Karlsson, Lennart
    Aktivitet: Kompetenscentra behövs. Goda erfarenheter av tvärdisciplinär forskning i Luleå1992Other (Other (popular science, discussion, etc.))
  • 31.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Computational Welding Mechanics2014In: Encyclopedia of Thermal Stresses, Dordrecht: Encyclopedia of Global Archaeology/Springer Verlag, 2014, p. 630-637Chapter in book (Refereed)
  • 32.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Deformations in butt-welding of large plates with special reference to the temperature dependence of the yield limit of the material1987In: Numerical methods in thermal problems: proceedings of the fifth international conference held in Montreal, Canada on June 29th - July 3rd, 1987 / [ed] R.W. Lewis, Swansea: Pineridge Press , 1987, p. 994-1005Conference paper (Refereed)
  • 33. Karlsson, Lennart
    Modeling in welding, hot powder froming and casting1977Collection (editor) (Other academic)
  • 34.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Numerical analysis of damped transient beam vibrations by use of Fourier transforms1985In: International Journal for Numerical Methods in Engineering, ISSN 0029-5981, E-ISSN 1097-0207, Vol. 24, no 4, p. 683-689Article in journal (Refereed)
    Abstract [en]

    The objective of the present study is to investigate the applicability of the Fourier transform technique to the analysis of vibrating damped beam structures. The practical use of the method is demonstrated by calculating a measure of the noise emitted by a vibrating damped beam. Different distributed Winkler-type foundations are studied as a means of noise reduction in the vibrating damped beam structure. This type of damping can be applied to the drill rods employed in rock drilling

  • 35. Karlsson, Lennart
    Plane stress fields induced by moving heat sources in butt-welding1977In: Journal of applied mechanics, ISSN 0021-8936, E-ISSN 1528-9036, Vol. 44, no 2, p. 231-236Article in journal (Refereed)
    Abstract [en]

    Mathematical models of the cooling of large butt-welded plates are investigated. One thermoelastic infinite plate and one thermoelastic semi-infinite plate are considered. On the infinite plate two concentrated heat sources of constant power move with constant velocity along a straight line toward each other. They meet and are then immediately removed from the plate. On the semi-infinite plate one concentrated heat source of constant power moves with constant velocity along a straight line perpendicularly toward the edge and is removed as it reaches the plate edge. The straight plate boundary is thermally adiabatic and mechanically free. It is shown that after removal of the heat source(s) such tensile stresses remain much longer in the semi-infinite plate than in the infinite plate. The transverse tensile stresses may explain the tendency of hot cracking in the end portion of a butt-weld.

  • 36. Karlsson, Lennart
    Stress fields induced by moving heat sources in butt welding of plates1976Doctoral thesis, comprehensive summary (Other academic)
  • 37.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Thermal stresses in welding1986In: Thermal stresses, Amsterdam: Elsevier, 1986, p. 299-389Chapter in book (Other academic)
  • 38.
    Karlsson, Lennart
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Thermomechanical finite element models for calculation of residual stresses due to welding1993In: Residual stresses: [papers presented at the European Conference on Residual Stresses, November 1992, Frankfurt a.M., Germany] / [ed] Viktor Hauk, DGM Informationsgesellschaft Verlag , 1993, p. 33-48Conference paper (Refereed)
    Abstract [en]

    Some different thermomechanical models for the calculation of residual deformations and stresses in welding are discussed. Among the models are three-dimensional finite element models, shell element models, combined 3-D and shell element models, plane stress and plane deformation models. The usefulness and application of the different models are demonstrated. In all models the material is assumed to be thermoelastic plastic with temperature dependent thermal and mechanical material properties. Volume changes due to phase transformations are accounted for. Effects of transformation plasticity on the calculated residual stresses are included in the discussions. It is concluded that it is of utmost importance to chose the proper model for the welding situation at hand, as it is not possible to adopt fully three-dimensional models where it may be desirable. Welding of HY80 is given as an example

  • 39.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Boman, Per-Olof
    Luleå tekniska universitet.
    Computer input data for transient dynamic analysis of a linear model of a bus1987Report (Other academic)
  • 40.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Boman, Per-Olof
    Transient dynamic analysis of a linear model of a bus1987In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 16, no 2, p. 75-89Article in journal (Refereed)
    Abstract [en]

    Transient analysis of a linear model of a bus was performed. In the experiment the right front wheel of the bus rolled over a bump and one acceleration, two axial forces in the wheel suspension and two bending moments in the frame of the bus were measured. The different parts of the bus were modeled by uniform Rayleigh-Timoshenko beams and rigid bodies. This beam element has a uniformly distributed stiffness, inertia and viscous and/or hysteretic damping along its axis. The loading of the bus due to the bump was in the theoretical analysis modeled by a prescribed transient displacement of the model of the wheel. The fast Fourier transform technique was utilized. Fairly good agreement between calculated and measured values was obtained.

  • 41.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Jeppsson, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Eliasson, P.
    Luleå tekniska universitet.
    Isaksson, Ola
    Volvo Aero Corporation.
    Integration of thermal-structural analysis in the product development process1997Conference paper (Refereed)
    Abstract [en]

    Trends of more team working and cross-functional activities in Integrated Product Development increases the requirements on the computer-aided engineering technology used. Experience of using solid models in a product development project at Volvo Aero is presented. Further, it is described how thermal boundary conditions, calculated using Computational Fluid Dynamics simulations, can be integrated with thermal structural analysis in a commercial Finite Element code. It is argued that incremental technology development using technology based on international standards, e.g., the STEP standard, is a low-risk, highly efficient strategy for improving multi-functional analysis systems.

  • 42.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Johanson, Mathias
    Alkit Communications AB.
    Improving vehicle diagnostics through wireless data collection and statistical analysis2007In: 66th IEEE Vehicular Technology Conference: VTC2007-Fall :Baltimore : proceedings : 30 September - 3 October, 2007, Baltimore, Maryland, Piscataway, NJ: IEEE Communications Society, 2007, p. 2184-2188Conference paper (Refereed)
    Abstract [en]

    Collection and analysis of diagnostic data from electronic control units is of paramount importance in the automotive industry, both from a life cycle support perspective, and as a tool in the product development. For pre-series test vehicles, access to diagnostic data is crucial in order to be able to track problems as early as possible in the development process, preventing serious faults to pass undetected into production vehicles. However, systematic collection of diagnostic data from test vehicles is complicated by the fact that pre-series vehicles are frequently unavailable for diagnostic read-outs, while away on test expeditions in rural areas, or being operated by taxi companies, or being otherwise inaccessible. In response, we propose a system for wireless read-out of diagnostic data, based on an embedded system installed in the test vehicles and a server component at the automotive company. Moreover, we present a number of computer-based tools for statistical analysis of diagnostic trouble codes, to aid engineers in processing the potentially very large amount of diagnostic dataata generated by the automated collection system. We strongly believe that wireless diagnostic collection systems, in combination with statistical analysis tools, will be a key component in meeting future demands on reduced development time, while the complexity of automotive electronics continue to grow. Initial results from our pilot trials with the tools described in this paper support this claim.

  • 43.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Jonsson, Mikael
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Näsström, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Trovie, L.
    Residual stresses and deformations in a welded thin-walled pipe1989In: Weld residual stresses and plastic deformation: papers / [ed] E. Rybicki; M. Shiratori, New York: American Society of Mechanical Engineers , 1989Conference paper (Refereed)
    Abstract [en]

    Deformations and stresses during butt-welding of a pipe are calculated as well as the residual deformations and stresses. The temperature field during welding is calculated using an analytical solution. The deformations and stresses are calculated by use of the finite element method. A thermo-elastoplastic material model is used. Special attention is paid to the influence of the volume changes due to phase transformations on the deformations (radial shrinkage) and the residual stresses. The calculated radial shrinkage and residual stresses are compared to experimental values. Good agreement was obtained.

  • 44.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Karlberg, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Editorial2013In: International Journal of Product Development, ISSN 1477-9056, E-ISSN 1741-8178, Vol. 18, no 1, p. 1-2Article in journal (Other academic)
  • 45.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Combined heat and stress-strain calculations1990In: Modeling of Casting, Welding and Advanced Solidification Processes V: 5th International conference on modeling of casting and welding processes : Papers / [ed] Michel Rappaz, Warrendale, Pa: Minerals, Metals & Materials Society, 1990, p. 187-202Conference paper (Refereed)
  • 46.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-ErikLuleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.Jonsson, Mikael
    Mechanical effects of welding: IUTAM Symposium, Luleå, Sweden, June 10-14, 19911992Collection (editor) (Other academic)
  • 47.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Jonsson, Mikael
    Josefson, L.
    Oddy, A.
    Modeling of residual stresses and distortion development1997In: Mathematical modelling of weld phenomena 3, London: Institute of Materials , 1997, p. 571-589Chapter in book (Other academic)
    Abstract [en]

    Four examples are used to illustrate the current ability to calculate residual stress and distortion in situations of varying complexity. The methodology used is capable of allowing for interactions between thermal, mechanical, and transformation processes. Experimental values for a 2.25Cr-1Mo ferritic stainless steel were used in the simulation. It seems possible to simulate most welding situations given sufficient computer resources

  • 48.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Lindström, John
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Functional Products - Goodbye to the industrial age2012In: Ericsson Business Review, ISSN 1653-9486, Vol. 18, no 2, p. 21-24Article in journal (Other (popular science, discussion, etc.))
  • 49.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Löfstrand, Magnus
    Larsson, Andreas
    Larsson, Tobias
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Törlind, Peter
    Elfström, Bengt-Olof
    Isaksson, Ola
    Information driven collaborative engineering: enabling functional product innovation2005In: Challenges in Collaborative Engineering: CCE '05 ; the knowledge perspective in collabotative engineering ; proceedings of the international workshop, 14th - 15th April 2005, Sopron, Hungary in conjunction with DDECS '05 / [ed] Gianni Jacucci, Interprint , 2005Conference paper (Refereed)
  • 50.
    Karlsson, Lennart
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Product and Production Development.
    Pahkamaa, Andreas
    Karlberg, Magnus
    Löfstrand, Magnus
    Goldak, John
    Carleton University & Goldak Technologies Inc., Ottawa.
    Pavasson, Jonas
    Mechanics of materials and structures: a simulation-driven design approach2011In: Journal of Mechanics of Materials and Structures, ISSN 1559-3959, E-ISSN 2157-5428, Vol. 6, no 1-4, p. 277-301Article in journal (Refereed)
    Abstract [en]

    Engineering product development has developed considerably over the past decade. In order for industry to keep up with continuously changing requirements, it is necessary to develop new and innovative simulation methods. However, few tools and methods for simulation-driven design have been applied in industrial settings and proven to actually drive the development and selection of the ideal solution. Such tools, based on fundamental equations, are the focus of this paper. In this paper the work is based on two cases of mechanics of materials and structures: welding and rotor dynamical simulations. These two examples of simulation-driven design indicate that a larger design space can be explored and that more possible solutions can be evaluated. Therefore, the approach improves the probability of innovations and finding optimal solutions. A calibrated block dumping approach can be used to increase the efficiency of welding simulations when many simulations are required.

12 1 - 50 of 98
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