Blar i NTNU Open på forfatter "Hopperstad, Odd Sture"

Viser treff 41-60 av 211

    • Damage and Failure in an X65 Steel Pipeline Caused by Trawl Gear Impact 

      Kristoffersen, Martin; Børvik, Tore; Langseth, Magnus; Hopperstad, Odd Sture; Ilstad, Håvar; Levold, Erik (Chapter, 2013)
      Offshore pipelines subjected to accidental impact loads from trawl gear or anchors may experience large global deformations and large local strains, creating a complex stress and strain history. In this study experiments ...

    • Deformation and Fracture of Impulsively Loaded Sandwich Panels 

      Wadley, Haydn N.G.; Børvik, Tore; Olovsson, Lars; Wetzel, J.J.; Dharmasena, Kumar P.; Hopperstad, Odd Sture; Deshpande, Vikram; Hutchinson, J.W. (Journal article; Peer reviewed, 2013)
      Light metal sandwich panel structures with cellular cores have attracted interest for multifunctional applications which exploit their high bend strength and impact energy absorption. This concept has been explored here ...

    • Deformation and strain localization in polycrystals with plastically heterogeneous grains 

      Khadyko, Mikhail; Marioara, Calin Daniel; Ringdalen, Inga Gudem; Dumoulin, Stephane; Hopperstad, Odd Sture (Journal article; Peer reviewed, 2016)
      A model of a polycrystalline material is studied, where each grain consists of several zones with different plastic properties. The size and configuration of the zones as well as their properties are mimicking the situation ...

    • Design and finite element simulations of aluminium foam-filled thin-walled tubes 

      Hanssen, Arve Grønsund; Reyes, Aase Gavina Roberg; Hopperstad, Odd Sture; Langseth, Magnus (Journal article; Peer reviewed, 2005)
      This paper presents experiences gained at SIMLab in modelling and design of aluminium-foam-filled tubes for structural applications. The main challenges for robust finite element simulations using explicit codes are outlined ...

    • Detailed investigation of the shearing mechanism of β" precipitates in Al-Mg-Si alloys 

      Christiansen, Emil; Marioara, Calin Daniel; Ringdalen, Inga Gudem; Bjørge, Ruben; Holmedal, Bjørn; Hopperstad, Odd Sture; Holmestad, Randi (Peer reviewed; Journal article, 2020)
      The mechanism behind shearing of β'' precipitates in Al-Mg-Si alloys during deformation is investigated by applying advanced transmission electron microscopy (TEM) techniques and frozen phonon multislice TEM image simulations ...

    • Ductile failure of aluminium plates: experiments, modelling and simulations 

      Espeseth, Vetle (Doctoral theses at NTNU;2023:65, Doctoral thesis, 2023)
      Numerical models and simulations are valuable tools to aid engineers in the design of products and structures and can help reduce the number of costly and time-consuming experiments needed. The modelling of ductile material ...

    • Ductile failure predictions using micromechanically-based computational models 

      Dæhli, Lars Edvard Blystad; Tekoglu, Cihan; Morin, David; Børvik, Tore; Hopperstad, Odd Sture (Peer reviewed; Journal article, 2022)
      Three different micromechanically-based computational models for fracture in porous ductile solids are compared and assessed. Model A is a unit cell model of a porous ductile solid comprising a uniform periodic distribution ...

    • Ductile fracture of aluminium alloys in the low to moderate stress triaxiality range 

      Tomstad, Asle Joachim (Doctoral theses at NTNU;2022:150, Doctoral thesis, 2022)
      This thesis investigates the effect of constituent particles on ductile fracture in 6000-series aluminium alloys in the low to moderate stress triaxiality range. In Part 1, tension tests on smooth and notched specimens ...

    • Ductile Fracture of Steel Sheets under Dynamic Membrane Loading 

      Gruben, Gaute; Morin, David; Langseth, Magnus; Hopperstad, Odd Sture (Journal article; Peer reviewed, 2017)
      Failure prediction assessment is conducted based on validated finite element simulations of impact tests performed on 1.8 mm dual-phase and 1.0 mm martensitic steel sheets. The sheets were clamped between two steel rings ...

    • Ductile-Brittle Transition in Offshore Steel 

      Hellum, Gry Myrmo (Master thesis, 2017)
      The main objective of this thesis was to investigate experimentally and numerically the main effects and interaction effects of temperature, strain rate and stress triaxiality on an offshore X65 steel. During preliminary ...

    • Dynamic Behaviour of a High-Strength Structural Steel at Low Temperatures 

      Perez-Martin, Maria Jesus; Holmen, Jens Kristian; Thomesen, Susanne; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2019)
      The main objective of this experimental study is to determine the effect of low temperatures on the mechanical behaviour of Strenx 960 Plus high-strength structural steel at different strain rates and stress triaxialities. ...

    • Dynamic strain ageing in an AlMg alloy at different strain rates and temperatures: Experiments and constitutive modelling 

      Xu, Jianbin; Holmedal, Bjørn; Hopperstad, Odd Sture; Manik, Tomas; Marthinsen, Knut (Peer reviewed; Journal article, 2022)
      Uniaxial tension tests at strain rates from to and temperatures from 298 to 418 K are performed to study the dynamic strain ageing (DSA) of an AA5182-O sheet. Digital image correlation (DIC) is used to obtain the stress-strain ...

    • Dynamic versus quasi-static loading of X65 offshore steel pipes 

      Kristoffersen, Martin; Børvik, Tore; Langseth, Magnus; Hopperstad, Odd Sture (Journal article; Peer reviewed, 2016)
      Anchors or trawl gear occasionally impact offshore pipelines, resulting in large local and global deformations. Impact velocities are typically less than 5 m/s, but local strain rates may be very high. In this study strain ...

    • The effect of constituent particles on the tear resistance of three 6000-series aluminium alloys 

      Qvale, Kristin; Thomesen, Susanne; Hopperstad, Odd Sture; Børvik, Tore (Peer reviewed; Journal article, 2022)
      This paper investigates the tear resistance of three cast and homogenized 6000-series alloys, namely AA6061, AA6063 and AA6110, all in temper T6, by means of Kahn tear tests. Of each alloy one commercial version and one ...

    • Effect of heat-treatment on the structural response of blast-loaded aluminium plates with pre-cut slits 

      Granum, Henrik; Aune, Vegard; Børvik, Tore; Hopperstad, Odd Sture (Journal article; Peer reviewed, 2019)
      This study investigates the structural response of blast-loaded aluminium plates with pre-cut slits. The 1.5 mm thick plates were tested after three different heat-treatments and with four different pre-cut slit geometries ...

    • Effect of pre-stretching on the mechanical behaviour of three artificially aged 6xxx series aluminium alloys 

      Granum, Henrik Møgster; Myhr, Ole Runar; Børvik, Tore; Hopperstad, Odd Sture (Peer reviewed; Journal article, 2021)
      The effect of pre-stretching on the mechanical behaviour of the aluminium alloys AA6063, AA6061 and AA6110 in temper T6 has been investigated. Uniaxial tensile tests and quasi-static axial crushing tests were conducted on ...

    • Effective behaviour of porous ductile solids with a non-quadratic isotropic matrix yield surface 

      Dæhli, Lars Edvard Blystad; Hopperstad, Odd Sture; Benallal, Ahmed (Journal article; Peer reviewed, 2019)
      In this study, we examine the macroscopic yielding of isotropic porous ductile solids having a matrix yield function dependent on the second and third deviatoric stress invariants. Numerical limit analyses using a ...

    • Effects of constituent particle content on ductile fracture in isotropic and anisotropic 6000-series aluminium alloys 

      Tomstad, Asle Joachim; Thomesen, Susanne; Børvik, Tore; Hopperstad, Odd Sture (Peer reviewed; Journal article, 2021)
      Tension tests on smooth and notched specimens were conducted for four 6000-series aluminium alloys to assess the effects of constituent particles on ductile fracture at different stress states. Two of the alloys are ...

    • Effects of heat treatment on the ballistic properties of AA6070 aluminium alloy 

      Holmen, Jens Kristian; Johnsen, Joakim; Jupp, S; Hopperstad, Odd Sture; Børvik, Tore (Journal article; Peer reviewed, 2013)
      The ballistic properties of the aluminium alloy AA6070 in different tempers are studied, using target plates of 20 mm thickness in tempers O (annealed), T4 (naturally aged), T6 (peak strength) and T7 (overaged). The ...

    • Effects of heat-treatment on the plastic anisotropy of extruded aluminium alloy AA6063 

      Khadyko, Mikhail; Marioara, Calin Daniel; Dumoulin, Stephane; Børvik, Tore; Hopperstad, Odd Sture (Journal article, 2017)
      The plastic anisotropy of aluminium alloys is known to depend not only on the crystallographic texture but also on the heat-treatment, and this effect has been studied on various alloys both experimentally and numerically. ...