Finding critical damage locations by Λ-filtering in finite-element modelling of a girth weld

Stefan Holmström (Corresponding Author), Anssi Laukkanen, Kim Calonius

    Research output: Contribution to journalArticleScientificpeer-review

    3 Citations (Scopus)

    Abstract

    In structures with uniform material properties, time dependent creep damage will develop in locations where the stress state is aggravated by triaxiality constraints. However, for non-uniform structures, such as welds, where several material zones (differing in microstructure and material properties) are present, the pin-pointing of the “weakest link” is even more challenging. For girth-welded pipes, the unfavourable conditions are known to be found in the vicinity of the heat-affected zone on the outer diameter. To find out how the triaxiality constraints influence accumulated “creep exhaustion”, three girth welds simulated for different steels have been studied using the Λ-filtering technique. The Λ-filtering has been developed for finite element modelling for visualising the combined effect of creep ductility, creep rate and triaxiality constraint evolution assuming rigid plastic deformation for the stress triaxiality-dependent part. In this work, the creep response of three-zone girth welds was studied. In the case of the P23 steel, data for a real (experimental) consumable was used and for the others, assumption on creep strength and creep curve shapes was made according to material property ratios. The creep strain rate formulation used for this work is the logistic creep strain prediction model and its multiaxial implementation has been run in the Comsol multiphysics software package. The results of the weld simulations predict similar behaviour for the P22 and P91 welds, with assumed weld metal behaviour closer to the base material, and differing behaviour for the P23 with an overmatching (experimental) weld metal.
    Original languageEnglish
    Pages (from-to)224-228
    Number of pages5
    JournalMaterials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
    Volume510-511
    DOIs
    Publication statusPublished - 2009
    MoE publication typeA1 Journal article-refereed
    Event11th International Conference of Creep and Fracture of Engineering Materials and Structures, CREEP 2008 - Bad Berneck, Germany
    Duration: 4 May 20089 May 2008

    Fingerprint

    triaxial stresses
    Creep
    Welds
    damage
    steels
    exhaustion
    creep strength
    heat affected zone
    Materials properties
    logistics
    Steel
    ductility
    metals
    plastic deformation
    strain rate
    Metals
    computer programs
    formulations
    microstructure
    curves

    Keywords

    • Constraint
    • Creep damage
    • FEA
    • Modelling
    • Welds
    • ProperTune

    Cite this

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    title = "Finding critical damage locations by Λ-filtering in finite-element modelling of a girth weld",
    abstract = "In structures with uniform material properties, time dependent creep damage will develop in locations where the stress state is aggravated by triaxiality constraints. However, for non-uniform structures, such as welds, where several material zones (differing in microstructure and material properties) are present, the pin-pointing of the “weakest link” is even more challenging. For girth-welded pipes, the unfavourable conditions are known to be found in the vicinity of the heat-affected zone on the outer diameter. To find out how the triaxiality constraints influence accumulated “creep exhaustion”, three girth welds simulated for different steels have been studied using the Λ-filtering technique. The Λ-filtering has been developed for finite element modelling for visualising the combined effect of creep ductility, creep rate and triaxiality constraint evolution assuming rigid plastic deformation for the stress triaxiality-dependent part. In this work, the creep response of three-zone girth welds was studied. In the case of the P23 steel, data for a real (experimental) consumable was used and for the others, assumption on creep strength and creep curve shapes was made according to material property ratios. The creep strain rate formulation used for this work is the logistic creep strain prediction model and its multiaxial implementation has been run in the Comsol multiphysics software package. The results of the weld simulations predict similar behaviour for the P22 and P91 welds, with assumed weld metal behaviour closer to the base material, and differing behaviour for the P23 with an overmatching (experimental) weld metal.",
    keywords = "Constraint, Creep damage, FEA, Modelling, Welds, ProperTune",
    author = "Stefan Holmstr{\"o}m and Anssi Laukkanen and Kim Calonius",
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    language = "English",
    volume = "510-511",
    pages = "224--228",
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    Finding critical damage locations by Λ-filtering in finite-element modelling of a girth weld. / Holmström, Stefan (Corresponding Author); Laukkanen, Anssi; Calonius, Kim.

    In: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing, Vol. 510-511, 2009, p. 224-228.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Finding critical damage locations by Λ-filtering in finite-element modelling of a girth weld

    AU - Holmström, Stefan

    AU - Laukkanen, Anssi

    AU - Calonius, Kim

    PY - 2009

    Y1 - 2009

    N2 - In structures with uniform material properties, time dependent creep damage will develop in locations where the stress state is aggravated by triaxiality constraints. However, for non-uniform structures, such as welds, where several material zones (differing in microstructure and material properties) are present, the pin-pointing of the “weakest link” is even more challenging. For girth-welded pipes, the unfavourable conditions are known to be found in the vicinity of the heat-affected zone on the outer diameter. To find out how the triaxiality constraints influence accumulated “creep exhaustion”, three girth welds simulated for different steels have been studied using the Λ-filtering technique. The Λ-filtering has been developed for finite element modelling for visualising the combined effect of creep ductility, creep rate and triaxiality constraint evolution assuming rigid plastic deformation for the stress triaxiality-dependent part. In this work, the creep response of three-zone girth welds was studied. In the case of the P23 steel, data for a real (experimental) consumable was used and for the others, assumption on creep strength and creep curve shapes was made according to material property ratios. The creep strain rate formulation used for this work is the logistic creep strain prediction model and its multiaxial implementation has been run in the Comsol multiphysics software package. The results of the weld simulations predict similar behaviour for the P22 and P91 welds, with assumed weld metal behaviour closer to the base material, and differing behaviour for the P23 with an overmatching (experimental) weld metal.

    AB - In structures with uniform material properties, time dependent creep damage will develop in locations where the stress state is aggravated by triaxiality constraints. However, for non-uniform structures, such as welds, where several material zones (differing in microstructure and material properties) are present, the pin-pointing of the “weakest link” is even more challenging. For girth-welded pipes, the unfavourable conditions are known to be found in the vicinity of the heat-affected zone on the outer diameter. To find out how the triaxiality constraints influence accumulated “creep exhaustion”, three girth welds simulated for different steels have been studied using the Λ-filtering technique. The Λ-filtering has been developed for finite element modelling for visualising the combined effect of creep ductility, creep rate and triaxiality constraint evolution assuming rigid plastic deformation for the stress triaxiality-dependent part. In this work, the creep response of three-zone girth welds was studied. In the case of the P23 steel, data for a real (experimental) consumable was used and for the others, assumption on creep strength and creep curve shapes was made according to material property ratios. The creep strain rate formulation used for this work is the logistic creep strain prediction model and its multiaxial implementation has been run in the Comsol multiphysics software package. The results of the weld simulations predict similar behaviour for the P22 and P91 welds, with assumed weld metal behaviour closer to the base material, and differing behaviour for the P23 with an overmatching (experimental) weld metal.

    KW - Constraint

    KW - Creep damage

    KW - FEA

    KW - Modelling

    KW - Welds

    KW - ProperTune

    U2 - 10.1016/j.msea.2008.04.107

    DO - 10.1016/j.msea.2008.04.107

    M3 - Article

    VL - 510-511

    SP - 224

    EP - 228

    JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

    JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

    SN - 0921-5093

    ER -