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",
journal = "Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing",
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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

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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

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DO - 10.1016/j.msea.2008.04.107

M3 - Article

VL - 510-511

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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 -