Modelling and verification of creep strain and exhaustion in a welded steam mixer

Stefan Holmström, Anssi Laukkanen, Juhani Rantala, Kari Kolari, Heikki Keinänen, O. Lehtinen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


    Structures operating in the creep regime will consume their creep life at a greater rate in locations where the stress state is aggravated by triaxiality constraints. Many structures, such as the welded steam mixer studied here, also have multiple material zones differing in microstructure and material properties. The 3-dimensional structure as such in addition to interacting material zones is a great challenge for finite element analysis (FEA), even to accurately pinpoint the critical locations where damage will be found. The studied steam mixer, made of 10CrMo 9-10 steel (P22), has after 100 000 hours of service developed severe creep damage in the several saddle point positions adjacent to nozzle welds. FE-simulation of long term behaviour of this structure has been performed taking developing triaxiality constraints, material zones and primary to tertiary creep regimes into account. The creep strain rate formulation is based on the logistic creep strain prediction (LCSP) model implemented to ABAQUS, including primary, secondary and tertiary creep. The results are presented using a filtering technique utilising the formulation of rigid plastic deformation for describing and quantifying the developing "creep exhaustion".
    Original languageEnglish
    Title of host publicationProceedings of the ASME 2008 Pressure Vessels & Piping Conference, PVP 2008
    Place of PublicationNew York, NY
    PublisherAmerican Society of Mechanical Engineers (ASME)
    ISBN (Print)978-0-7918-4830-2
    Publication statusPublished - 2008
    MoE publication typeA4 Article in a conference publication
    EventASME 2008 Pressure Vessels and Piping Conference, PVP 2008 - Chicago, Illinois, United States
    Duration: 27 Jul 200831 Jul 2008


    ConferenceASME 2008 Pressure Vessels and Piping Conference, PVP 2008
    Abbreviated titlePVP 2008
    Country/TerritoryUnited States
    CityChicago, Illinois


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