Change search
Refine search result
1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Azizoğlu, Yağız
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Gärdsback, Mattias
    Sandvik Materials Technology, R&D, Sandviken.
    Sjöberg, Bengt
    Sandvik Materials Technology, R&D, Sandviken.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Finite Element Analysis of cold pilgering using elastic roll dies2017In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 207, p. 2370-2375Article in journal (Refereed)
    Abstract [en]

    A finite element model of cold pilgering with elastic roll dies have been developed and used to investigate the influence of roll die deformation on the material flow, contact region, roll separating force and tube dimensions. Full scale experiments were performed to validate the contact surface and tube dimensions. The results show that the influence of roll die flattening is not significant on the contact length. However, elastic deformation of roll die has strong influence on both the wall thickness reduction and roll separating force. Thus it is recommended to consider elasticity of roll dies when forces and tube dimensions are estimated.

  • 2.
    Galstyan, V.
    et al.
    CNR IDASC SENSOR Lab.
    Comini, E.
    CNR IDASC SENSOR Lab.
    Faglia, G.
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    CNR-IDASC SENSOR Lab and Dipartimento di Chimica e Fisica per l'Ingegneria e per i Materiali.
    Brisotto, M.
    INSTM and Chemistry for Technologies Laboratory.
    Bontempi, E.
    INSTM and Chemistry for Technologies Laboratory.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    Fabrication of TiO 2 and TiO 2 nanotubular arrays and their gas sensing properties2011In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 25, p. 757-760Article in journal (Refereed)
    Abstract [en]

    Pure TiO 2 and TiO 2 nanotubular arrays were successfully sensitized. Nanotubular arrays were prepared by electrochemical anodization of thin films of Ti and of Ti-Nb deposited on alumina substrates with two different roughness. Morphological characterization and functional properties are presented. The gas sensing properties of TiO 2 and TiO 2 nanotubes with different gases have been tested in a wide range of operating temperatures. © 2011 Published by Elsevier Ltd.

  • 3.
    Girhammar, Ulf Arne
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Källsner, Bo
    Department of Building Technology, Linnaeus University.
    Horizontal Stabilisation of Sheathed Timber Frame Structures Using Plastic Design Methods – Introducing a Handbook: Part 1: Design Principles for Horizontal Stabilisation2016In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 161, p. 618-627Article in journal (Refereed)
    Abstract [en]

    The authors have developed a plastic design method for sheathed timber frame shear walls. It has been presented and discussed for inclusion in Eurocode 5 and a Swedish handbook has been presented. In the plastic method, you can choose to transfer the anchoring force via the leading stud to the substrate, corresponding to a fully anchored shear wall (no uplift of studs), but you can also choose to utilize the sheathings to transfer the tensile force via the sheathing-to-framing joints to the substrate by anchoring the bottom rail, corresponding to a partially anchored shear wall (studs experience uplift). By the plastic method several alternatives for anchoring the wall are possible and they can also be combined in such a way that each of them take a portion of the uplifting force, e.g. through a simple tying down device, through the sheathing-to-framing joints and through anchoring of the shear wall to the transverse wall. The method also makes it possible to include the load-bearing capacity of wall segments including openings. The handbook treats primarily shear walls, but for the sake of completeness some aspects of the roof and floor diaphragms are also discussed. The interior force distribution in sheathed timber frame walls weak in shear is discussed, as are the fundamental difference between the effect of vertical loads on the stabilisation of walls which are rigid or weak in shear, and how the plastic design method is applied to multi-storey timber buildings

  • 4.
    Girhammar, Ulf Arne
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Källsner, Bo
    Department of Building Technology, Linnaeus University.
    Horizontal Stabilisation of Sheathed Timber Frame Structures Using Plastic Design Methods – Introducing a Handbook: Part 2: Design of Joints and Anchoring Devices2016In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 161, p. 628-635Article in journal (Refereed)
    Abstract [en]

    In this part 2, the practical design and strength of a number of different joints is described: (1) Sheathing-to-framing joints – the plastic design method is based on the premise that the load-displacement relationship of the sheathing-to-framing joints has sufficiently large plastic deformation capacity; the sheathing-to-framing joints have great influence on the load-carrying capacity of the wall; (2) Stud-to-rail joints – by utilizing the shear capacity of the stud-to-rail joints, the plastic design method can be simplified and the load-carrying capacity can be increased; (3) Hold down devices for the (leading) stud – the capacity of the tying down force of the hold down determines whether the shear wall will act as fully or partially anchored; tying down the shear walls by connecting them to the transverse walls leads to a 3-dimensioonal behaviour that is a very favourable for the load-carrying capacity and the stiffness of the shear wall; through transverse walls the anchoring of the leading stud can be reduced or eliminated (those types of transverse wall connections are not discussed in detail in this paper); and (4) Anchoring devices for the bottom rail – in partially anchored shear walls it is necessary that the bottom rail is anchored to the substrate against uplift. Characteristic values for the different types of joints are given. Also, joints between the panels in the walls, roofs and floors are described briefly.

  • 5.
    Girhammar, Ulf Arne
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Källsner, Bo
    Department of Building Technology, Linnaeus University.
    Horizontal Stabilisation of Sheathed Timber Frame Structures Using Plastic Design Methods – Introducing a Handbook: Part 3: Basics of the Plastic Design Method2016In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 161, p. 636-644Article in journal (Refereed)
    Abstract [en]

    Design of shear walls has been a topic of major discussions to develop a common European code for design of timber structures. The main problem has been that shear walls are fastened to the substrate in different ways in different countries and that this fact must be reflected in the code. In this part the requirements are given that must be met for the ductile characteristics of the sheathing-to-framing joints in order for the plastic design method to be applicable. The method is based on the plastic lower bound theory. The fundamental prerequisites for the method are that the static equilibrium for the structure is fulfilled and that the sheathing-to-framing joints are ductile. What requirements that should be made on the mechanical properties of the joints for the plastic design methods to be applicable and the precaution measures to take to avoid brittle behaviour are discussed. The two main principles for anchoring of sheathed timber frame shear walls, fully and partially anchored, are illustrated showing the static behaviour of the walls and the force distribution in the framing members and the sheathings. In addition, a general description of the design in the serviceability limit state is given. For medium-rise and taller buildings the serviceability limit state needs to be taken into account. There are no specified criteria for deformations in the present code.

  • 6.
    Girhammar, Ulf Arne
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Källsner, Bo
    Department of Building Technology, Linnaeus University.
    Horizontal Stabilisation of Sheathed Timber Frame Structures Using Plastic Design Methods – Introducing a Handbook: Part 4: Design in Ultimate Limit State2016In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 161, p. 645-654Article in journal (Refereed)
    Abstract [en]

    In this part 4, the horizontal load-carrying capacity of fully and partially anchored sheathed timber frame walls subjected to arbitrary vertical loads is presented for different models. For fully anchored walls, the elastic method is summarised (for comparison reasons) and a corresponding simple plastic method is presented. For partially anchored walls, three different plastic methods are presented: (1) no contact forces between adjacent sheets occur; (2) contact forces between the sheets; and (3) contact forces between the sheets and also with stud-to-rail joints taken into account. All the proposed plastic models are based on plastic characteristics of the sheathing-to-framing joints and that a plastic lower bound method is used. The proposed models are simple and flexible and can be applied to different wall geometries, boundary conditions, loading configurations, and number of storeys. The developed plastic design methods for fully and partially anchored sheathed timber frame shear walls have been verified through extensive analytical and experimental studies. This part is the last one in a series introducing the handbook to the international community.

  • 7.
    Golling, Stefan
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Östlund, Rickard
    Gestamp HardTech.
    Bergman, Greger
    Gestamp HardTech.
    Åkerström, Paul
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Oldenburg, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Modelling of Plastic Deformation and Fracture in Hot Stamped Steel with Multi-Phase Microstructure2017In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 207, p. 687-692Article in journal (Refereed)
    Abstract [en]

    Hot stamping is an industrialized technique with the aim of improving material properties by heat treatment and forming of a component in a single production step. Within the field of hot stamping the method of tailored material properties evolved. Components with tailored material properties possess different mechanical properties in designated areas. The mechanical properties in a blank are modified by the formation of different microstructures. Martensite is a microstructure with high strength but low ductility, ferrite has lower strength but higher ductility. Using special tooling tough martensite and soft ferrite can be placed in adjacent sections in a blank. Between those sections a transition zone consisting of a mixed microstructure exists with mechanical properties between martensite and ferrite. Transition zones possess intermediate cooling rates, hence formation of bainite and composites of bainite and another phase can from.

    This paper presents an approach of modelling the complete process from austenitized blank to fracture. The method presented relies on the prediction of phases formed during cooling using an austenite decomposition model. In the course of ferrite formation the carbon content in the remaining austenite increases, the carbon content in austenite influences formation of additional daughter phases. The estimated phase composition is used in a homogenization scheme to predict the hardening of the material during plastic deformation. Fracture in the different microstructural phases is predicted using the strain decomposition provided by the homogenization and a fracture criteria. The homogenization scheme and the fracture criteria use measured data from single phase microstructures, i.e. ferrite, bainite and martensite.

    A heat treatment process for tensile test specimens is used to produce samples with different volume fractions of the microstructures ferrite, bainite and martensite. The pre-cut specimens are austenitized, ferrite is formed in a second furnace with lower temperature, bainite and martensite are formed by the use of a temperature controlled plane tool.

    Prediction of the phase content in mixed microstructures showed good agreement with microstructural characterization and therefore results can be used as input value for the homogenization. Comparing experimental and numerical results for a variety of different mixed microstructures good agreement in the prediction of hardening and fracture is found.

    It is concluded that the use of a homogenization method combined with a fracture model can be used to predict the mechanical response of mixed microstructures. The method described in the present work can be applied in the development of hot stamped components.

  • 8.
    Gustafsson, Andreas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Möller, Mikael
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Experimental and Numerical Investigation of Ratcheting in Pressurized Equipment2015In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 130, p. 1233-1245Article in journal (Refereed)
    Abstract [en]

    part of a project within the Swedish nuclear industry with the objective to investigate the performance of different constitutive models in ratchet simulation, an extensive experimental program has been conducted on pressurized tube specimens. In total 30 test specimens made of two different materials, 316L and P235, have been manufactured and tested. In order to determine material properties, monotonic tensile load and internal pressure experiments have been performed. The remaining test specimens have been used for ratcheting experiments. The experimental results show ratcheting in the hoop direction when the tube is subjected to certain combinations of internal pressure and cyclic axial strains. The higher the pressure is and the larger the strain ranges are, the higher the ratcheting response becomes. Measured ratcheting strains are compared to numerical simulations using different constitutive models. In this paper the interrelated models of Prager, Armstrong-Frederick and Chaboche are investigated. In addition to these, the Besseling model is investigated. Based on the result from this investigation, recommendations on how to conduct ratcheting simulation of pressurized equipment subjected to cyclic secondary loading are presented

  • 9.
    Haller, Martin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stehn, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Increasing the Accuracy of a Prefab Building Design Process Simulation Using Simulated Annealing2014In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 85, p. 214-221Article in journal (Refereed)
    Abstract [en]

    Monte-Carlo simulation analysis has been discussed in project management literature as tool for proactive scheduling and to gain better insights into projects which are characterized by a high level of complexity and uncertainty, such as the design phase of prefab building projects. The application of simulation as proactive scheduling tool in construction projects is hampered by limited accessibility of proper input data, though, because of long project duration, the often temporary organization and multidisciplinary nature of such projects. In this study we use simulated annealing to adjust parameters of a simulation model for which the simulation outcome is sensitive to data perturbation by making use of data from related parameters which is easier to estimate. The applicability of the approach was demonstrated on a real life project, the construction of a 1100 m2 residential building in Sweden. More precisely, we used Design Structure Matrix simulation, i.e. an activity network based Monte-Carlo simulation technique with which stochastic project evolution (deviations from the planned activity sequence due to unexpected iteration of sub-processes) can be simulated, to model the workflow of the design process of the observed project. Then, by means of the simulated annealing approach, we adjusted the rework probabilities (model parameter) such that the frequencies of executed activities in simulated activity sequences fitted the frequencies as observed in the real project. Adjusting input data by using prior knowledge of the dependencies of the project activities and cross analysis with related data that is easy to estimate would help to increase the accuracy of simulations when access to statistical data of the input variable in question is limited. The suggested approach is interesting for practitioners who work with standardized design processes (e.g. as part of standardized building systems) and continuous improvement

  • 10.
    Kapogianni, Elena
    et al.
    Ethniko Metsovio Polytechnico, School of Rural and Surveying Engineering, Athens, National Technical University of Athens.
    Sakellariou, Michael G.
    Ethniko Metsovio Polytechnico, School of Rural and Surveying Engineering, Athens, National Technical University of Athens.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Springman, Sarah M.
    Institute of Geotechnical Engineering, ETH Hönggerberg, Zürich.
    Investigation of the Mechanical Behaviour of the Interface between Soil and Reinforcement, via Experimental and Numerical Modelling2016In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 143, p. 419-426Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to investigate the interface properties between soil and reinforcement, via experimental and numerical modelling of reinforced slopes. In particular, several scale models were built and tested under enhanced gravity in the geotechnical drum centrifuge at ETH Zurich and corresponding prototype numerical models were analyzed via a finite element stress analysis code. Optical fibre sensors were attached on the reinforcement layers of the experimental scaled models in order to measure linear strain during the increase of the g-level, and the results were compared to linear strain that was derived by the numerical analysis of the correspondent prototype reinforced slopes. The interface between soil and reinforcement was expressed in terms of normal and shear stiffness on the soil-reinforcement boundary and different values were tested in order to achieve validation of the experimental and numerical results.

  • 11.
    Niewiadomski, Pawel
    et al.
    Faculty of Civil Engineering, Wroclaw University of Technology.
    Cwirzen, Andrzej
    Aalto University, Espoo.
    Hola, Jerzy
    Faculty of Civil Engineering, Wroclaw University of Technology.
    The influence of an additive in the form of selected nanoparticles on the physical and mechanical characteristics of self-compacting concrete2015In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 111, p. 601-606Article in journal (Refereed)
    Abstract [en]

    The influence of nanoparticle additives on the physical and mechanical characteristics of hardened self-compacting concrete (SCC) was studied. Research included SCC concretes modified with different amounts of SiO2, TiO2 and Al2O3 nanoparticle additives and one reference concrete made without nanoparticles. Rheological properties, microstructure and compressive strength were determined. The obtained results showed that SiO2 and Al2O3 additions worsened the workability while the compressive strength was increased in the case of SiO2 addition. All studied nanomaterials densified the microstructure of the hydrated binder matrix

  • 12.
    Ongo, E
    et al.
    Industrial Technology Development Institute, DOST.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab, University of Brescia.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Antonelli, A
    Dipartimento di Scienze della Terra, Universita di Modena e Reggio Emilia.
    Montevecchi, G
    Dipartimento di Scienze della Terra, Universita di Modena e Reggio Emilia.
    Sberveglieri, Veronica
    CNR IDASC SENSOR Lab, University of Brescia.
    Concina, Isabella
    CNR IDASC SENSOR Lab.
    Sevilla, F
    University of Santo Tomas, Manila.
    Chemometric discrimination of philippine civet coffee using electronic nose and gas chromatography mass spectrometry2012In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 47, p. 977-980Article in journal (Refereed)
    Abstract [en]

    This study presents a practical and promising approach to profile the headspace aroma attributes of Philippine civet coffee using electronic nose (E-nose) and gas chromatography mass spectrometry (GCMS). Chemometric pattern method was applied to enhance the discrimination of civet coffee against its control coffee beans (not eaten by civet animal). E-nose analysis revealed that aroma characteristic is one of the most important quality indicators of civet coffee. The result was supported by GCMS analysis. The chromatographic fingerprints indicated that civet coffee differed with their control beans in terms of composition and concentration of individual volatile constituents. Chemometric discrimination of E-nose and GCMS data demonstrated a clearly separated civet from their control coffees indicating that cultivar and geographic origins dictate the aroma and volatiles variations in coffee.

1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf