Dynamic behaviour of pipelines in power plants

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


    Dynamic excitation due to a pipe break can cause pipe to abruptly displace and hit the components, instrumentation and equipment nearby. In order to minimize the risk of such damage by pipe whips in a power plant, different types of restraints and supports are designed for the pipelines. The usability of different types of elements provided by Abaqus, a commercial general-purpose finite element code, in modelling the dynamic behaviour of pipelines is tested. A relatively short pipe line section with one bend and one restraint is chosen as a test case. Simple and typical nuclear power plant pipeline geometry and materials are chosen. The stiffness of the restraint as well as the flexural stiffness of the pipe cross-section are solved with static compression simulations with a detailed model using three-dimensional solid and shell elements. After that, the model is substituted with couple of simpler models using pipe and/or elbow elements for the pipe and a spring element for the restraint. The eigenmodes of models are calculated and compared with each other. The pipe whip is simulated with nonlinear dynamic analyses with the most adequate models according to the preliminary linear analyses. The displacement and stress results of different models are compared with each other and the reliability and adequacy of different element types are discussed. Sensitivity study is made by varying analysis type, material properties, mesh density, element properties and inner pressure. The results of the most adequate simple models with the right combinations of special-purpose elements provided by Abaqus corresponded well to the ones of the much larger three-dimensional solid and shell element models. The post-yield behaviour of the pipe steel material has some notable effect on the behaviour of the pipe in a guillotine pipe break. Obviously, rate dependence makes the structure slightly dynamically stiffer. The inner pressure of the pipe and its assumed decay after the pipe break has a major influence on the results. It is shown, how the stress distribution along the pipe axis, around the cross-section and through the thickness of the wall can be solved with elbow elements on a fairly detailed level. Long pipe runs with many supports and restraints should preferably be modelled with simple structural elements such as pipe and elbow elements and special-purpose elements in order to save time and numerical errors due to overly large models.
    Original languageEnglish
    Title of host publicationBaltica VIII
    Subtitle of host publicationLife Management and Maintenance for Power Plants
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    ISBN (Electronic)978-951-38-7592-3
    ISBN (Print)978-951-38-7591-6
    Publication statusPublished - 2010
    MoE publication typeB3 Non-refereed article in conference proceedings
    EventBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
    Duration: 18 May 201020 May 2010

    Publication series

    SeriesVTT Symposium


    ConferenceBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants


    Dive into the research topics of 'Dynamic behaviour of pipelines in power plants'. Together they form a unique fingerprint.

    Cite this