• Global buckling of pipelines - A study on different soil models 

      Park, Seoyeon (Master thesis, 2016)
      Pipelines are essential units as a energy transportation method nowadays. Buckling behaviors have been recognized as majority because it can cause sudden disconnection of pipelines and this may lead the pipeline to ...
    • Impact analysis of flexible riser 

      Brandt, Ulrikke (Master thesis, 2014)
      Research shows 35% of damage to flexible pipes occurs within the first year. A minimum of these failures are from poor design or manufacturing problems, since factories conduct Factory Acceptance Tests (FAT). Additionally, ...
    • In-Line Vibrations of Flexible Pipes 

      Ulveseter, Jan Vidar; Sævik, Svein (Chapter; Peer reviewed, 2017)
      A semi-empirical prediction tool for pure in-line vortex-induced vibrations is under development. The long-term goal is to be able to realistically model the dynamic behavior of free spanning pipelines exposed to arbitrary ...
    • Investigation on the Performance of the Universal Buoyancy System 

      Staalesen, Odd Eivind Solø (Master thesis, 2014)
      Future increase in the market demand for liquefied natural gas (LNG) will pose new challenges to the existing infrastructure for LNG distribution. The Universal Buoyancy System (UBS) seeks to contribute to the solution of ...
    • Investigations of Shear Interaction and Stress in Flexible Pipes and Umbilicals 

      Dai, Tianjiao (Doctoral theses at NTNU;2018:368, Doctoral thesis, 2018)
      The present thesis deals with numerical modeling and experimental testing related to dynamic stress behavior of flexible pipes and umbilicals, with particular focus on shear interaction and friction effects. For the ...
    • Jordmodeller og utmatning av fritthengende stigerør 

      Grindstad, Anne Cecilie (Master thesis, 2016)
      Denne masteravhandlingen omhandler utvikling og anvendelse av jordmodeller for beskrivelse av jord-stigerør interaksjon. På dypt vann, er jorda bestående av leire noe som introduserer sensitive parameterer. Det gjør ...
    • motion control during offshore lift operations 

      Andersen, Sten Martin Grønlund (Master thesis, 2017)
      Offshore lifting is present in many offshore operations. Offshore lifting operations is very sensitive to environmental loads which reduces the weather window for the entire operation. The weather criteria for offshore ...
    • Non-Linear Clay Soil Model for Lateral Pipe-Soil Interaction 

      Agusta, Arifian; Ji, Guomin; Sævik, Svein (Chapter; Peer reviewed, 2016)
      This paper describes implementation and application of nonlinear lateral soil models for pipeline lateral buckling analysis. Several lateral soil models have been developed in the past and the model developed by Verley is ...
    • NON-LINEAR SOIL MODELS FOR PIPELINE AND RISER ANALYSIS 

      Irman, Arifian Agusta (Master thesis, 2015)
      This thesis describes the development and application of non-linear soil models in pipeline and riser design. A non-linear soil model is typically employed when investigating a complex pipe-soil interaction problem. Two ...
    • Non-linear time domain analysis of cross-flow vortex-induced vibrations 

      Thorsen, Mats Jørgen; Sævik, Svein; Larsen, Carl Martin (Journal article; Peer reviewed, 2017)
      A previously proposed hydrodynamic load model for time domain simulation of cross-flow vortex-induced vibrations (VIV) is modified and combined with Morison's equation. The resulting model includes added mass, drag and a ...
    • Numerical analysis of buckling failure in flexible pipe armor wires 

      Yang, Xu; Sævik, Svein; Sun, Liping (Journal article; Peer reviewed, 2015)
      Flexible pipes may be exposed to high axial compression and bending during deep-water installation. As the compression force is mainly sustained by the tensile armor layers, this may result in localized lateral or radial ...
    • Numerical Analysis of Combined VIV and Slug Flow in Time Domain 

      Knudsen, Tor Huse; Sævik, Svein; Thorsen, Mats Jørgen (Chapter; Peer reviewed, 2016)
      Vortex induced vibrations (VIV) and slug flow are two important aspects for marine risers conveying a multiphase flow, and should be carefully examined due to the influence on the fatigue life of the structure. This article ...
    • Numerical investigation of collapse and ductile fracture in X65 offshore pipelines subject to external pressure, bending and axial loads 

      Hafstad, Jens Mjøen (Master thesis, 2016)
      An offshore pipeline during S-laying in deep water may be subject to high pressure, bending and tensile loads. In the event of loss of tension the pipe may buckle for sufficiently high external pressures and bending moments. ...
    • OMAE2017-62644 The Effect of Stick Stiffness of Friction Models on the Bending Behavior in Non-Bonded Flexible Risers 

      Dai, Tianjiao; Ye, Naiquan; Sævik, Svein (Chapter; Peer reviewed, 2017)
      This paper investigates the effect of stick stiffness on the bending behavior in non-bonded flexible risers. The stick stiffness was normally implemented in the friction model for calculating the friction stress between ...
    • On prediction of torque in flexible pipe reeling operations using a Lagrangian-Eulerian FE framework 

      Longva, Vegard; Sævik, Svein (Journal article; Peer reviewed, 2016)
      In this paper a new framework for FE simulation of reeling operations that utilizes a Lagrangian–Eulerian description of the beam kinematics is proposed. In contrast to the conventional Lagrangian approach, the material ...
    • Optimization of passive heave compensation during Subsea Factory heavy lift operations 

      Zhou, Weitian (Master thesis, 2017)
      This thesis is about the study of the effect of heave passive compensation during subsea factory heavy lift operations. All the analysis are based on the data provided by Peter Sandvik, Marintek. The main objective is to ...
    • Pipeline Walking of High Pressure/Temperature Flowlines 

      Tveråmo, Camilla (Master thesis, 2013)
      The offshore pipeline industry are facing more complex design challenges as the oiland gas industry moves into deeper water in search for hydrocarbons. One of thesechallenges are related to high pressure/high temperature ...
    • Reduction of trawl impact loads on pipelines resting exposed on the seabed 

      Krogstadmo, Truls Wanvik (Master thesis, 2019)
      I dag finnes havbunnsinstallasjoner rundt omkring i Nordsjøen og Barentshavet med rørledninger som strekker seg totalt over 8800 kilometer på norsk sokkel. Rørledninger eksisterer rundt offshore-anlegget og er koblet til ...
    • Response of Flexible Risers in Bend Stiffener Area 

      Løseth, Kim (Master thesis, 2011)
      Flexible risers is a vital part of a floating production system (FPS). In order to predict the riser life time, many procedure may be applied. In this thesis it is assumed that the pipe could be represented with help of ...
    • Rigid Pipelay Curve Stability 

      Andersson, Christian (Master thesis, 2014)
      Pipeline installation would generally involve curved sections in the horizontal plane, due to existing subsea infrastructure or natural seabed characteristics. At a small curve radius, the lateral seabed friction could be ...