Constitutive modeling of hydrogen cracking

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

Abstract

Hydrogen cracking in multiple-pass weld metals occurs when accumulating hydrogen concentration exceeds a certain critical level. This accumulation via diffusion is a thermally activated, continuing process taking place throughout welding, driven also by the emerging residual stresses. The results of diffusion analyses are difficult to quantify in terms of cracking risk since no reliable coupling between the local hydrogen concentration and material damage has been available. Numerical analyses enabling solution of hydrogen diffusion and local concentration in welds having complex geometries are performed. A predefined temperature solution is used as an input to a finite element transient diffusion analysis. In the mass diffusion problem, a three-dimensional residual stress field is input to describe the pressure stress dependency of the transient diffusion process. The resulting concentration profiles are considered by use of a novel damage mechanics material model in a finite element analysis (FEA) with a cohesive zone modeling framework, which links the local concentration to a continuum mechanics damage description. By use of the damage mechanics constitutive material model, conditions for hydrogen cracking are evaluated for a multipass butt weld. The results of the mass diffusion analysis are in agreement with experimental findings and measured hydrogen concentrations, while the damage mechanics analysis is illustrated to provide means for evaluating the rupture process by use of continuum mechanics.
Original languageEnglish
Title of host publicationBALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages419-429
ISBN (Electronic)951-38-6294-1
ISBN (Print)951-38-6293-3
Publication statusPublished - 2004
MoE publication typeB3 Non-refereed article in conference proceedings
EventBALTICA VI - Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
Duration: 8 Jun 200410 Jun 2004

Publication series

SeriesVTT Symposium
Number234
ISSN0357-9387

Conference

ConferenceBALTICA VI - Life Management and Maintenance for Power Plants
CountryFinland
CityHelsinki-Stockholm
Period8/06/0410/06/04

Fingerprint

Hydrogen
Mechanics
Welds
Residual stresses
Continuum damage mechanics
Continuum mechanics
Welding
Finite element method
Geometry
Metals
Temperature

Keywords

  • ProperTune

Cite this

Laukkanen, A., & Nevasmaa, P. (2004). Constitutive modeling of hydrogen cracking. In BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2 (pp. 419-429). Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 234
Laukkanen, Anssi ; Nevasmaa, Pekka. / Constitutive modeling of hydrogen cracking. BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2. Espoo : VTT Technical Research Centre of Finland, 2004. pp. 419-429 (VTT Symposium; No. 234).
@inproceedings{911b6eb9d9a84f41a02bab2d508cce30,
title = "Constitutive modeling of hydrogen cracking",
abstract = "Hydrogen cracking in multiple-pass weld metals occurs when accumulating hydrogen concentration exceeds a certain critical level. This accumulation via diffusion is a thermally activated, continuing process taking place throughout welding, driven also by the emerging residual stresses. The results of diffusion analyses are difficult to quantify in terms of cracking risk since no reliable coupling between the local hydrogen concentration and material damage has been available. Numerical analyses enabling solution of hydrogen diffusion and local concentration in welds having complex geometries are performed. A predefined temperature solution is used as an input to a finite element transient diffusion analysis. In the mass diffusion problem, a three-dimensional residual stress field is input to describe the pressure stress dependency of the transient diffusion process. The resulting concentration profiles are considered by use of a novel damage mechanics material model in a finite element analysis (FEA) with a cohesive zone modeling framework, which links the local concentration to a continuum mechanics damage description. By use of the damage mechanics constitutive material model, conditions for hydrogen cracking are evaluated for a multipass butt weld. The results of the mass diffusion analysis are in agreement with experimental findings and measured hydrogen concentrations, while the damage mechanics analysis is illustrated to provide means for evaluating the rupture process by use of continuum mechanics.",
keywords = "ProperTune",
author = "Anssi Laukkanen and Pekka Nevasmaa",
year = "2004",
language = "English",
isbn = "951-38-6293-3",
series = "VTT Symposium",
publisher = "VTT Technical Research Centre of Finland",
number = "234",
pages = "419--429",
booktitle = "BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2",
address = "Finland",

}

Laukkanen, A & Nevasmaa, P 2004, Constitutive modeling of hydrogen cracking. in BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2. VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 234, pp. 419-429, BALTICA VI - Life Management and Maintenance for Power Plants, Helsinki-Stockholm, Finland, 8/06/04.

Constitutive modeling of hydrogen cracking. / Laukkanen, Anssi; Nevasmaa, Pekka.

BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2. Espoo : VTT Technical Research Centre of Finland, 2004. p. 419-429 (VTT Symposium; No. 234).

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

TY - GEN

T1 - Constitutive modeling of hydrogen cracking

AU - Laukkanen, Anssi

AU - Nevasmaa, Pekka

PY - 2004

Y1 - 2004

N2 - Hydrogen cracking in multiple-pass weld metals occurs when accumulating hydrogen concentration exceeds a certain critical level. This accumulation via diffusion is a thermally activated, continuing process taking place throughout welding, driven also by the emerging residual stresses. The results of diffusion analyses are difficult to quantify in terms of cracking risk since no reliable coupling between the local hydrogen concentration and material damage has been available. Numerical analyses enabling solution of hydrogen diffusion and local concentration in welds having complex geometries are performed. A predefined temperature solution is used as an input to a finite element transient diffusion analysis. In the mass diffusion problem, a three-dimensional residual stress field is input to describe the pressure stress dependency of the transient diffusion process. The resulting concentration profiles are considered by use of a novel damage mechanics material model in a finite element analysis (FEA) with a cohesive zone modeling framework, which links the local concentration to a continuum mechanics damage description. By use of the damage mechanics constitutive material model, conditions for hydrogen cracking are evaluated for a multipass butt weld. The results of the mass diffusion analysis are in agreement with experimental findings and measured hydrogen concentrations, while the damage mechanics analysis is illustrated to provide means for evaluating the rupture process by use of continuum mechanics.

AB - Hydrogen cracking in multiple-pass weld metals occurs when accumulating hydrogen concentration exceeds a certain critical level. This accumulation via diffusion is a thermally activated, continuing process taking place throughout welding, driven also by the emerging residual stresses. The results of diffusion analyses are difficult to quantify in terms of cracking risk since no reliable coupling between the local hydrogen concentration and material damage has been available. Numerical analyses enabling solution of hydrogen diffusion and local concentration in welds having complex geometries are performed. A predefined temperature solution is used as an input to a finite element transient diffusion analysis. In the mass diffusion problem, a three-dimensional residual stress field is input to describe the pressure stress dependency of the transient diffusion process. The resulting concentration profiles are considered by use of a novel damage mechanics material model in a finite element analysis (FEA) with a cohesive zone modeling framework, which links the local concentration to a continuum mechanics damage description. By use of the damage mechanics constitutive material model, conditions for hydrogen cracking are evaluated for a multipass butt weld. The results of the mass diffusion analysis are in agreement with experimental findings and measured hydrogen concentrations, while the damage mechanics analysis is illustrated to provide means for evaluating the rupture process by use of continuum mechanics.

KW - ProperTune

M3 - Conference article in proceedings

SN - 951-38-6293-3

T3 - VTT Symposium

SP - 419

EP - 429

BT - BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Laukkanen A, Nevasmaa P. Constitutive modeling of hydrogen cracking. In BALTICA VI - Life Management and Maintenance for Power Plants. Vol. 2. Espoo: VTT Technical Research Centre of Finland. 2004. p. 419-429. (VTT Symposium; No. 234).