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  • 51. Josefsson, B.L.
    et al.
    Karlsson, Lennart
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Thermo-mechanical FE-analysis of the fabrication of a Cu-Fe canister for spent nuclear fuel1995Inngår i: 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. , 1995Konferansepaper (Fagfellevurdert)
  • 52. Kalhori, Vahid
    et al.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Edberg, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Coupled thermomechanical simulation of hot rolling using an adaptive mesh1998Inngår i: Simulation of materials processing : theory, methods and applications: international conference on numerical methods in industrial forming processes, NUMIFORM '98 / [ed] J. Huétink; F.P.T. Baaijens, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1998, s. 689-693Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Coupled thermo-mechanical analysis of hot rolling is performed. The efficiency and accuracy when using an adaptive remeshing technique is compared with using a uniform, fine mesh. The advantages and limitations of the different techniques are discussed

  • 53.
    Kalhori, Vahid
    et al.
    AB Sandvik Coromant, Sandviken.
    Wedberg, Dan
    AB Sandvik Coromant, Sandviken.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Simulation of mechanical cutting using a physical based material model2010Inngår i: International Journal of Material Forming, ISSN 1960-6206, E-ISSN 1960-6214, Vol. 3, nr Suppl. 1, s. 511-514Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A dislocation density material model based on model-based-phenomenology has been used to predict orthogonal cutting of stainless steel Sanmac 316L. The chip morphology and the cutting forces are used to validate the model. The simulated cutting forces and the chip morphology showed good conformity with practical measurements. Furthermore, simulation of cutting process utilizing the dislocation density based material model improved understanding regarding material behaviour such as strain hardening and shear localization at the process zone.

  • 54.
    Karlsson, Lennart
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Jonsson, Mikael
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Näsström, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Trovie, L.
    Residual stresses and deformations in a welded thin-walled pipe1989Inngår i: Weld residual stresses and plastic deformation: papers / [ed] E. Rybicki; M. Shiratori, New York: American Society of Mechanical Engineers , 1989Konferansepaper (Fagfellevurdert)
    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.

  • 55.
    Karlsson, Lennart
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Combined heat and stress-strain calculations1990Inngår i: 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, s. 187-202Konferansepaper (Fagfellevurdert)
  • 56.
    Karlsson, Lennart
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Lindgren, Lars-ErikLuleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.Jonsson, Mikael
    Mechanical effects of welding: IUTAM Symposium, Luleå, Sweden, June 10-14, 19911992Collection/Antologi (Annet vitenskapelig)
  • 57.
    Karlsson, Lennart
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jonsson, Mikael
    Josefson, L.
    Oddy, A.
    Modeling of residual stresses and distortion development1997Inngår i: Mathematical modelling of weld phenomena 3, London: Institute of Materials , 1997, s. 571-589Kapittel i bok, del av antologi (Annet vitenskapelig)
    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

  • 58.
    Karlsson, Lennart
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Ökvist, M.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Näsström, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Design of die and its effect on wear in cup forming1995Inngår i: Simulation of materials processing: theory, methods and applications : proceedings of the fifth international conference on numerical methods in industrial forming processes, Ithaca, New York, USA, 18 - 21 June 1995 / NUMIFORM '95 / [ed] Shan-Fu Shen; Paul R Dawson, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1995, s. 587-591Konferansepaper (Fagfellevurdert)
  • 59. Larsson, C.
    et al.
    Holden, T.M.
    Bourke, M.A.M
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Spatially resolved residual stress measurements in a welded specimen using neutron diffraction2002Konferansepaper (Fagfellevurdert)
  • 60.
    Larsson, C.
    et al.
    Linköping University.
    Holden, T.M.
    Los Alamos National Laboratory.
    Bourke, M.A.M.
    Los Alamos National Laboratory.
    Stout, M.
    Los Alamos National Laboratory.
    Teauge, J.
    Los Alamos National Laboratory.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Measurement and modeling of residual stress in a welded Haynes® 25 cylinder2005Inngår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 399, nr 1-2, s. 49-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An experimental and simulation study of residual stresses was made in the vicinity of a gas tungsten arc weld, used to join a hemispherical end cap to a cylinder. The capped cylinder is used in a satellite application and was fabricated from a Co-based Haynes® 25 alloy. The cylinder was 34.7 mm in outer diameter and 3.3 mm in thickness. The experimental measurements were made by neutron diffraction and the simulation used the implicit Marc finite element code. The experimental resolution was limited to approximately 3 mm parallel to the axis of the cylinder (the weld was 6 mm in the same direction) and comparison over the same volume of the finite element prediction showed general agreement. Subject to the limited spatial resolution, the largest experimentally measured tensile residual stress was 180 MPa, located at the middle of the weld. However, the predictions suggest that there are regions in the weld where average tensile residual stresses as much as 400 MPa exist. One qualitative disparity between the model and the experiments was that the measurement included a larger degree of asymmetry on either side of the weld than predicted by the model.

  • 61. Lindberg, B.
    et al.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Molin, Nils-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Jansson, E.V.
    Kungliga tekniska högskolan, KTH.
    Experiments with transient waves in a violin bridge1994Inngår i: C A S Journal, ISSN 1053-7694, Vol. 2, nr 6, s. 24-27Artikkel i tidsskrift (Fagfellevurdert)
  • 62.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Activity: Euromech 221, The mechanical effects of welding1987Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 63.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Computational welding mechanics for safety critical components2006Inngår i: Welding in South-East Asia: a challenge for the future : proceedings, Bangkok: Welding Institute of Thailand , 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A simulation approach based on computational welding mechanics (CWM) is presented for an industrial context, aircraft engine manufacturing, where safety is of paramount importance, the technology transfer process developed at Volvo Aero Corporation to ensure qualified welding simulations is described, and a modelling methodology including calibration and validation procedures is outlined. Aspects of the simulation and modelling methodologies are discussed such as accuracy levels and the shortcomings of thermomechanical models and finite element analysis. The use of strain rate jump tests and Satoh tests for CWM validation is analysed and application to the turbine exhaust case of the PW2000 engine is reported

  • 64.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Computational welding mechanics: thermomechanical and microstructural simulations2007Bok (Annet vitenskapelig)
  • 65.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Current state of welding simulations2001Inngår i: Simulation of materials processing: theory, methods and applications : proceedings of the 7th International conference on numerical methods in industrial forming processes - NUMIFORM 2001 / [ed] Ken-ichiro Mori, Lisse: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 2001, s. 1113-1118Konferansepaper (Fagfellevurdert)
  • 66.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Deformations and stresses in butt-welding of plates: numerical simulation and experimental verification1985Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Deformation and stresses in butt-welding of plates were studied. The work includes numerical simulation and experimental verification. The simulations were performed by use of the finite element method. Temperature dependence of material properties and phase transformations were considered. A thermo-elastoplastic material model was used. Plane stress conditions were assumed. Automatic butt-welding of plates without backing needs close tolerances of joint geometry. The thermally induced deformations and stresses are of great importance for joint geometry during welding. Therefore the change of gap width in front of the moving arc has been of special interest in these studies. The residual stresses, which may affect inservice behaviour of welded plates, were also calculated and measured. The tack-welds were found to influence the change in gap width in front of the moving arc. A proper tack-welding procedure is important in order to avoid large changes in gap width during butt-welding. The tack-welds should be made as soon after each other as possible. The sequence in which the tack-welds are made also affect the change in gap width. The gap width increased during the last part of the butt-welding in the simulations performed in this work. This increase was larger for wide plates than for narrow plates. Residual stresses close to the weld were large. The effective stress reached the yield limit of the material in the weld line.

  • 67.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Design of small and effective finite element systems1986Inngår i: Engineering computations, ISSN 0264-4401, E-ISSN 1758-7077, Vol. 3, nr 3, s. 202-208Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A system consisting of a preprocessor, a finite element program and a postprocessor has been developed. Some features which make preprocessors and postprocessors user-friendly are described. Although microcomputers become more advanced it is still important that the finite element programs are fast and that they need small central memory. Programming details which accomplish this are also described. A Fortran program is appended which can assist the programmer who wants to implement the described routines for fast calculating of the shape functions and their derivatives.

  • 68.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Finite element modeling and simulation of welding. Part 1: Increased complexity2001Inngår i: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 24, nr 2, s. 141-192Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simulation of welding has advanced from the analysis of laboratory setups to real engineering applications during the last three decades. This development is outlined and the directions for future research are summarized in this review, which consists of three parts. This part shows that the increased complexity of the models gives a better description of the engineering applications. The important development of material modeling and computational efficiency are outlined in Parts 2 and 3, respectively.

  • 69.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Finite element modeling and simulation of welding. Part 2: Improved material modeling2001Inngår i: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 24, nr 3, s. 195-231Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simulation of welding has advanced from the analysis of laboratory setups to real engineering applications during the last three decades. This development is outlined and the directions for future research are summarized in this review, which consists of three parts. The material modeling is maybe the most crucial and difficult aspect of modeling welding processes. The material behavior may be very complex for the large temperature range considered.

  • 70.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Finite element modeling and simulation of welding. Part 3: Efficiency and integration2001Inngår i: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 24, nr 4, s. 305-334Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Welding simulation has advanced from the analysis of laboratory setups to real engineering applications during the last three decades. This development is outlined and the directions for future research are summarized in this review, which consists of three parts. This parts focuses on computational strategies and how they are integrated with other methods to facilitate the use of simulations in engineering. These developments have lead to the increased application of welding simulations in industry.

  • 71.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Finite element simulation of welding residual stresses and deformations2001Inngår i: Simulation der Fügetechniken: Potentiale und Grenzen : Beiträge zum DaimlerChrysler-Technologiekolloquium / [ed] Werner Pollmann, Verl. für Schweißen und Verwandte Verfahren, DVS-Verl. , 2001Konferansepaper (Fagfellevurdert)
  • 72.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Finite element simulation of welding residual stresses and distortions2001Inngår i: Simulation der Fügetechniken - Potentiale und Grenzen: Beiträge zum DaimlerChrysler-Technologiekolloquium / [ed] W. Pollmann; D. Radaj, Verl. für Schweißen und Verwandte Verfahren, DVS-Verl. , 2001, s. 69-80Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Principles, developments and applications of finite element modelling of residual stresses and deformations in fusion welding are reviewed. Details are given of finite element analysis of different phenomena: thermomechanical, thermal, and mechanical (large deformations, material behaviour). Engineering applications of two-dimensional and three-dimensional models are described. Improvements in models are summarised (more detailed analysis, treatment of complex geometry and multirun welds).

  • 73.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Improvements of the program "A versatile two-dimensional mesh generator with automatic bandwidth reduction"1987Inngår i: Computers & structures, ISSN 0045-7949, E-ISSN 1879-2243, Vol. 25, nr 4, s. 637-638Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Some simple modifications of the Fortran-code for the mesh generator of L. L. Durocher and A. Gasper are described. The changes make it possible to exclude five large data arrays and at the same time speed up the calculations somewhat

  • 74.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Integrated Design of Material, Manufacturing, Product and Performance2016Inngår i: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 7, s. 53-58Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ever-increasing emphasis on sustainable growth affects mechanical engineering tremendously. The components and products must be efficient, durable and light. Potential cost and weight savings without compromising performance can be realized by extending the design space of engineering design to include manufacturing process as well as material chemistry. This requires more advanced computational support than what is common in today's Computer Aided Design. The paper proposes a modelling approach for evaluation the integrated effects of material and manufacturing on component performance. Material and process models are the key ingredients and are exemplified in the paper.

  • 75.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Modelling for residual stresses and deformations due to welding: "knowing what isn't necessary to know".2002Inngår i: Mathematical Modelling of Weld Phenomena 6 / [ed] H. Cerjak; H.K.D.H. Bhadeshia, London: Maney Publishing (for The Institute of Materials, Minerals and Mining) , 2002, s. 491-518Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A discussion is presented on the thermomechanical simulation of the welding process in general and modelling of residual stresses and deformations in particular, in order to better understand what factors affect the accuracy of modelling and thus determine what information needs to be included and what can be ignored in the modelling process. A number of thermomechanical models are classified based on their accuracy. The concept of weld restraint is discussed and related to residual stresses and deformations. The influence of material modelling and simplifications in geometry on residual stress and deformation simulation is also considered for single run and multirun welds.

  • 76.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Modelling strain induced martensite formation during forming2005Inngår i: VIII International Conference on Computational Plasticity: COMPLAS VIII / [ed] E. Oñate; D. R. J. Owen, International Center for Numerical Methods in Engineering (CIMNE), 2005, s. 275-278Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Olson-Cohen model for strain-induced martensite formation is combined with a mixture rule for material properties in order to create a material model that can be used in simulations forming of components made of HyTensXTM. The model cannot capture the effect of plastic strain at higher temperatures on martensite formation during later straining at lower temperatures. However, the model is expected to work well for common forming processes.

  • 77.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Models for forming simulations of metastable austenitic stainless steel2004Inngår i: Materials Processing and Design: Modeling, Simulation and Applications (NUMIFORM 2004) / [ed] Somnath Ghosh, Melville, NY: American Institute of Physics (AIP), 2004, s. 1748-1753Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work is part of a project dedicated to find accurate and reliable tools for prediction of welding and post weld heat treatment. In other parts of the project, a simulation method for combined welding and heat treatment simulations of the component was developed and different plastic/viscoplastic material models have been compared, these models included effects of phase changes. These simulations were made using an axisymmetric finite element model. The current paper presents welding and heat treatment simulations of the same aerospace component but now using a three-dimensional shell model. The results are compared with the previously used axisymmetric model. The simulations revealed that the two first welds have the greatest influents on a 'key dimension'. From the simulation, it can be concluded that the three-dimensional model give better prediction of the dimension based on measurement performed but not presented here. The simulation presented in this paper is part of an aerospace component called Turbine Exhaust Case which is a fabricated structure made of a martensitic stainless steel.

  • 78.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Numerical modelling of welding2006Inngår i: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 195, nr 48-49, s. 6710-6736Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper describes the application of the finite element method to predict the thermal, material and mechanical effects of welding; Computational Welding Mechanics (CWM). The most common numerical approach used in CWM is only described shortly. The paper focuses on different modelling aspects. The most important modelling issues are the models for heat input and material behaviour. Finally, some recent applications are reviewed and future developments are discussed.

  • 79.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Phase transformations and material properties of low alloy steels1995Inngår i: Thermal stresses '95: proceedings of the First International Symposium on Thermal Stresses and Related Topics, June 5 - 7, 1995, Shizuoka University, Hamamatsu, Japan, Shizuoka University , 1995, s. Appendix 3.17-Konferansepaper (Fagfellevurdert)
  • 80.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Temperature fields in simulation of butt-welding of large plates1986Inngår i: Communications in Applied Numerical Methods, ISSN 0748-8025, Vol. 2, nr 2, s. 155-164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Temperature fields were calculated by the use of analytical solutions instead of the finite element method. The analytical solutions were studied in order to find possible simplifications in the thermal analysis. The thermal material properties were assumed to be independent of temperature in the analytical solutions. The heat flow in the welding direction was neglected in one of these solutions. Three different analytical solutions were studied in the five simulations performed. The mechanical analysis was performed by the finite element method. A thermo-elastoplastic formulation, considering temperature-dependent mechanical material properties, was adopted. Volume changes due to phase transformations were also accounted for. Change in gap width in front of the moving arc and residual stresses were calculated in the mechanical analysis.

  • 81.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    The use of simulations and need of experiments in material processing1996Inngår i: Current advances in mechanical design and production VI: proceedings of the Sixth Cairo University International MDP Conference, Cairo, 2-4 January 1996 / [ed] Mohamed E. Elarabi; Abdalla S. Wifi, Oxford: Pergamon Press, 1996, s. 149-161Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents some cases of simulation material processing performed by the author. Each type of process is outlined and the possible gain in design of manufacturing process and/or product is pointed out. Furthermore, some specific problems of the simulations are outlined. Simulation is used to calculate accumulated plastic strains and residual stresses during welding steel sheets and copper cylinder s

  • 82.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Understanding welding stress and distortion using computational welding mechanics2011Inngår i: Minimization of Welding. Distortion and Buckling: Modelling and implementation, Oxford: Woodhead Publishing Materials , 2011, s. 22-78Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Computational welding mechanics (CWM) is challenging to analyse owing to the thermomechanics and associated effects of microstructural evolution on material behaviour that have to be accounted for. Mastering CWM makes it possible for welded structures to be designed and enables engineers and researchers to simulate many other manufacturing processes that share the same challenges. In this chapter, the physics of welding stresses and distortions and corresponding analysis methods and model simplifications are introduced. Key issues in CWM are heat input models and material modelling, which are given special attention in the final sections

  • 83.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Welding and heat treatment of alloys2014Inngår i: Encyclopedia of Thermal Stresses, Dordrecht: Encyclopedia of Global Archaeology/Springer Verlag, 2014, s. 6558-6567Kapittel i bok, del av antologi (Fagfellevurdert)
  • 84.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Welding simulation revisited1999Inngår i: Thermal stresses '99: [proceedings] / [ed] Jacek J. Skrzypek; Hetnarski Hetnarski, Kraków: Bratni Zew , 1999, s. 185-188Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the early, often referenced papers, by Andersson 1, is reviewed. Butt welding of two low carbon steel plates is simulated by using the finite element method (FEM). Good agreement between simulations and experiments were obtained except at the lower side of the plate. Different material modeling alternatives have been used in order to find out the reason for this discrepancy

  • 85.
    Lindgren, Lars-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Welding stresses2014Inngår i: Encyclopedia of Thermal Stresses, Dordrecht: Encyclopedia of Global Archaeology/Springer Verlag, 2014, s. 6594-6600Kapittel i bok, del av antologi (Fagfellevurdert)
  • 86.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Alberg, Henrik
    Domkin, K.
    Constitutive modelling and parameter optimisation2003Inngår i: Computational plasticity VII : fundamentals and applications: proceedings of the Seventh Conference on Computational Plasticity held in Barcelona, Spain, 7 - 10 April 2003 / [ed] D.R.J. Owen, International Center for Numerical Methods in Engineering (CIMNE), 2003Konferansepaper (Fagfellevurdert)
  • 87.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Babu, Bijish
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Charles, Corinne
    Högskolan Väst.
    Wedberg, Dan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Simulation of manufacturing chains and use of coupled microstructure and constitutive models2010Inngår i: Finite Plasticity and Visco-plasticity of Conventional and Emerging Materials: the 16th International Symposium on Plasticity & its Current Applications ; January 3 - 8, 2010, Marriott Resort, St. Kitts / [ed] Akhtar S Khan; Babak Farrokh, Fulton, Md.: NEAT PRESS , 2010Konferansepaper (Annet vitenskapelig)
  • 88.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Carlestam, A.
    SSAB Oxelösund AB.
    An improved two-dimensional model of flame cutting1993Inngår i: COMMP '93: International Conference on Computer-Assisted Materials Design and Process Simulation, 6 - 9 September, 1993, Nippon Toshi Center, Tokyo, Japan ; proceedings, Tokyo: ISIJ , 1993, s. 141-146Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Flame-cutting of a large plate is simulated. Neglecting the heat flow in the cutting direction makes it possible to use a two-dimensional finite element method. A cross-section transverse to the cutting direction is modelled. Three different assumptions regarding the normal strain in the cutting direction are compared. They are called plane strain, generalized plane strain and plane deformation. They all give residual stresses that agree well with measurements. The plane deformation assumptions improve this agreement to achieve a low computational cost.

  • 89.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Carlestam, A.
    SSAB Oxelösund AB.
    Jonsson, Mikael
    Computational model of flame-cutting1993Inngår i: Journal of engineering materials and technology, ISSN 0094-4289, E-ISSN 1528-8889, Vol. 115, nr 4, s. 440-445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A computational model for simulation of flame-cutting has been developed. Two different cutting conditions are compared with respect to the residual stresses. The first case is a plate cut at room temperature and the other is the cutting of a preheated plate. The model depends on measured micro-structure to estimate the required heat input. The model is verified by comparing the calculations for the preheated plate with experimentally obtained residual stresses. Lower residual stresses in the preheated plate prevents subsequent cracking

  • 90.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Domkin, K.
    Dalarna University.
    Hansson, Sofia
    Dislocations, vacancies and solute diffusion in physical based plasticity model for AISI 316L2008Inngår i: Mechanics of materials (Print), ISSN 0167-6636, E-ISSN 1872-7743, Vol. 40, nr 11, s. 907-919Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A physical based model for the evolution of flow stress of AISI 316L from room temperature up to 1300 °C, strains up to 0.6 and strain rates from 0.0005 up to 10 s-1 is developed. One set of tests have been used for model calibration and another more complex set of tests for its validation. The model is based on a coupled set of evolution equations for dislocation density and (mono) vacancy concentration. Furthermore, it includes the effect of diffusing solutes in order to describe dynamic strain ageing (DSA). The model described the overall flow stress evolution well with exception of the details of the effect of the DSA phenomenon. Its numerical solution is implemented in a format suitable for large-scale finite element simulations.

  • 91.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Edberg, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Contact forces and deformations in plate rolling1989Inngår i: Numerical methods in industrial forming processes: proceedings of the 3rd International Conference on Numerical Methods in Industrial Forming Processes, Fort Collins, Colorado, 26 - 30 June 1989 / NUMIFORM 89 / [ed] Erik G. Thompson, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1989, s. 331-336Konferansepaper (Fagfellevurdert)
  • 92.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Edberg, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Explicit versus implicit finite element formulation in simulation of rolling1990Inngår i: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 24, s. 85-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The computational efficiency of the explicity finite element code DYNA2D and the implicit code NIKE2D are compared in the case of simulation of rolling. It is found that the explicit code is preferable. The advantages of the explicit formulation will be even more pronounced in three-dimensional simulations

  • 93.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Edberg, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Åkerström, Paul
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Zhang, Zhao
    Dalian University of Technology, Dalian, China.
    Modeling of thermal stresses in low alloy steels2019Inngår i: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 42, nr 6, s. 725-743Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Computing the evolution of thermal stresses accurately requires appropriate constitutive relations. This includes both the thermal and mechanical aspects, as temperature is the driver to thermal stresses. The paradigm of Integrated Computational Materials Engineering (ICME) aims at being able to quantitatively relate process-structure-property of a material. The article describes physics based models, denoted bridging elements, which are one step towards the vision of ICME. They couple material structure with heat capacity, heat conductivity, thermal and transformation strains and elastic properties for hypo-eutectoid steels. The models can account for the chemical composition of the steel and its processing, i.e. thermomechanical history, giving the evolution of the microstructure and the corresponding properties.

  • 94.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Fisk, Martin
    Materials Science, Technology and Society, Malmö Högskola.
    Dislocation density based plasticity model coupled with precipitate model2013Inngår i: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 535 - 536, s. 125-128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A dislocation density based plasticity model is applied to two variants of steels. One is an austenitic (fcc) stainless steel with ordered precipitates and the other is a Ti-Nb microalloyed (bcc) steel. Precipitate distributions are measured and this information is combined with appropriate precipitate hardening models. The flow stress model is also calibrated for an nickel-based superalloy where it is combined with a model for precipitate growth

  • 95.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Gyhlesten Back, Jessica
    Department of Materials Technology, Dalarna University, Falun, Sweden.
    Elastic properties of ferrite and austenite in low alloy steels versus temperature and alloying2019Inngår i: Materialia, ISSN 2589-1529, Vol. 5, artikkel-id 100193Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Models for elastic properties, as a function of temperature, are required when simulating various thermo-mechanical processes. A model for hypoeutectoid steels is proposed that accounts for this temperature dependency as well as the influence of alloying. The model consists of separate parts for the ferrite and austenite phases. The latter also includes a specific contribution due to ferromagnetism. The model is calibrated versus iron and evaluated against various steels.

  • 96.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Hedblom, Erika
    Luleå tekniska universitet.
    Modelling of addition of filler material in large deformation analysis of multipass welding2001Inngår i: Communications in Numerical Methods in Engineering, ISSN 1069-8299, E-ISSN 1099-0887, Vol. 17, nr 9, s. 647-657Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modelling of multipass welding by defining the complete computational model at the start of the analysis requires special procedures for activation of elements at the times when the corresponding parts of the welds are made. The developed logic for handling this is applicable in any situation where elements are defined in an initial geometry which has been changed at the time when the elements are activated as in a large deformation analysis. The current implementation is for two-dimensional models but can be extended to three-dimensional cases as well

  • 97.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Josefsson, B.L.
    Chalmers University of Technology.
    Karlsson, Lennart
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Thermo-mechanical FE-analysis of residual stresses and stress redistribution in butt welding of a copper canister for spent nuclear fuel2002Inngår i: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 212, nr 1-3, s. 401-408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transient and residual temperature, stress and strain field present during electron beam welding of a plane copper end to a canister for spent nuclear fuel is calculated by the use of FEM. The subsequent stress redistribution is calculated up to 10,000 years. The canister consists of two concentric cylinders, an inner steel cylinder containing the spent nuclear fuel and an outer copper cylinder. It was found that the maximum plastic strain (plastic+creep) accumulated in the (possibly brittle) heat affected zone is ≈7%, which seems to be well below the reported ductility for the copper used.

  • 98.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-Åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Josefsson, L.
    Chalmers University of Technology.
    Karlsson, Lennart
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Thermo-mechanical FE-analysis of residual stresses and stress redistribution in butt welding of a copper canister for spent nuclear fuel1999Inngår i: Structural mechanics in reactor technology: transactions of the 15th International Conference on Structural Mechanics in Reactor Technology, Seoul, Korea, August 15 - 20, 1999, SMiRT 15 / [ed] Sung Pil Chang, International Association for Structural Mechanics in Reactor Technology , 1999Konferansepaper (Fagfellevurdert)
  • 99.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    McDill, J.M.J.
    Carleton University, Ottawa.
    Oddy, Alan S.
    Oddy/McDIll Numerical Investigations Sciences, Inc..
    Automatic remeshing for three-dimensional finite element simulation of welding1997Inngår i: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 147, nr 3-4, s. 401-409Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Three-dimensional finite element simulation of electron beam welding of a large copper canister has been performed. The use of an automatic remeshing algorithm, based on a graded hexahedral element was found to be effective. With this algorithm the strongly nonlinear thermomechanical effects locally close to the moving heat source can accurately be modelled using a dense element mesh that follows the heat source.

  • 100.
    Lindgren, Lars-Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Jonsson, Mikael
    Accuracy and efficiency in computational plasticity1991Inngår i: Proceedings of the International Conference on Mechanics of Solids and Structures: Nanyang Technological University ; 11 - 13 September 1991 / [ed] Daniel T. Lwin; Frank W. Travis, Singapore: World Scientific and Engineering Academy and Society, 1991Konferansepaper (Fagfellevurdert)
1234 51 - 100 of 171
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