0
Research Papers: Materials Technology

Sensitivity of Plastic Response of Defective Pipeline Girth Welds to the Stress-Strain Behavior of Base and Weld Metal

[+] Author and Article Information
Stijn Hertelé

FWO Flanders Aspirant,
Laboratory Soete,
Ghent University,
Technologiepark Zwijnaarde 903,
9052 Zwijnaarde, Belgium
e-mail: Stijn.Hertele@UGent.be

Wim De Waele

e-mail: Wim.DeWaele@UGent.be

Rudi Denys

e-mail: Rudi.Denys@UGent.be

Matthias Verstraete

e-mail: Matthias.Verstraete@UGent.be
Laboratory Soete,
Ghent University,
Technologiepark Zwijnaarde 903,
9052 Zwijnaarde, Belgium

Contributed by the Ocean Offshore and Arctic Engineering Division of ASME for publication in the JOURNALOF OFFSHORE MECHANICSAND ARCTIC ENGINEERING. Manuscript received March 8, 2011; final manuscript received April 16, 2012; published online February 22, 2013. Assoc. Editor: Pingsha Dong.

J. Offshore Mech. Arct. Eng 135(1), 011402 (Feb 22, 2013) (8 pages) Paper No: OMAE-11-1027; doi: 10.1115/1.4007049 History: Received March 08, 2011; Revised April 16, 2012

One of the key parameters influencing the acceptability of a pipeline girth weld defect subjected to remote plastic deformation is the strength mismatch between weld and base metal. However, no single definition exists for weld strength mismatch, as it can be defined either on the basis of yield stress, ultimate tensile stress or any intermediate flow stress. To investigate the relevance of such definitions, the authors have performed a series of analyses of curved wide plate tests, using a validated parametric finite element model. The results indicate that, whereas yield stress overmatch determines crack driving force for small plastic strains, ultimate tensile stress overmatch is the more important parameter for advanced plastic strains and determines the eventual failure mode. Further, the strain capacity and exact crack driving force curve are additionally determined by uniform elongation and crack growth resistance.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Denys, R., De Waele, W., Lefevre, A., and De Baets, P., 2004, “An Engineering Approach to the Prediction of the Tolerable Defect Size for Strain-Based Design,” Proceedings of the 4th International Conference on Pipeline Technology, Ostend, Belgium, pp.163–182.
British Standards Institution, 2005, “BS7910. Guide on Methods for Assessing the Acceptability of Flaws in Metallic Structures,”, London, UK.
European Fitness for Service Network, 2008, “FITNET. Fitness for Service Procedure,” MK8: Procedure, Vol.1.
Motohashi, H., and Hagiwara, N., 2007, “Analytical Study of Effects of Strength Matching on Strain Capacity,” Proceedings of the 17th International Offshore and Polar Engineering Conference, Lisbon, Portugal, pp.3101–3106.
Kibey, S., Wang, X., Minnaar, K., Macia, M. L., Fairchild, D. P., Kan, W. C., Ford, S. J., and Newbury, B., 2010, “Tensile Strain Capacity Equations for Strain-Based Design of Welded Pipelines,” Proceedings of the 8th International Pipeline Conference, Calgary, Alberta, Canada, Paper No. IPC2010-31661.
Macia, M. L., Kibey, S., Arslan, H., Bardi, F., Ford, S. J., Kan, W. C., Cook, M. F., and Newbury, B., 2010, “Approaches to Qualify Strain-Based Designed Pipelines,” Proceedings of the 8th International Pipeline Conference, Calgary, Alberta, Canada, Paper No. IPC2010-31662.
Denys, R., and Lefevre, A., 2009, “UGent Guidelines for Curved Wide Plate Testing,” Proceedings of the 5th International Conference on Pipeline Technology, Ostend, Belgium.
Kan, W. C., Weir, M., Zhang, M. M., Lillig, D. B., Barbas, S. T., Macia, M. L., and Biery, N. E., 2008, “Strain-Based Pipelines: Design Consideration Overview,” Proceedings of the 18th International Offshore and Polar Engineering Conference, Vancouver, British Columbia, Canada, pp.174–181.
Ramberg, W., and Osgood, W. R., 1943, “Description of Stress-Strain Curves by Three Parameters,”, National Advisory Committee for Aeronautics, Washington D.C., Technical Note No. 902.
Canadian Standards Association, 2007, “CSA Z662. Oil & Gas Pipeline Systems,” Canada.
American Petroleum Institute, 2007, “API 1104, Welding of Pipelines and Related Facilities,” Washington D.C.
Denys, R., De Baets, P., Lefevre, A., and De Waele, W., 2002, “Material Tensile Properties in Relation to the Failure Behavior of Girth Welds Subject to Plastic Longitudinal Strains,” Proceedings of the International Conference on Application and Evaluation of High-Grade Linepipes in Hostile Environments, Yokohama, Japan, pp.159–172.
Denys, R., Hertelé, S., De Waele, W., and Lefevre, A., 2009, “Estimate of Y/T Ratio and Uniform Elongation Capacity of Pipeline Steels From Yield Strength,” Proceedings of the Pipeline Technology Conference2009, Ostend, Belgium.
Hertelé, S., De Waele, W., and Denys, R., “Full-Range Stress-Strain Behaviour of Contemporary Pipeline Steels: Part II. Estimation of Model Parameters,” Int. J. Press. Vess. Piping, 92, pp.27–33. [CrossRef]
British Energy Generation Ltd., 2001, “R6 Revision 4, Assessment of the Integrity of Structures Containing Defects,” East Kilbride, UK.
Hertelé, S., De Waele, W., and Denys, R., 2011, “A Generic Stress-Strain Model for Metallic Materials With Two-Stage Strain Hardening Behaviour,” Int. J. Nonlinear Mech., 46, pp.519–531. [CrossRef]
American Petroleum Institute, 2007, “API 5L, Specification for Line Pipe,” Washington D.C.
Hertelé, S., De Waele, W., and Denys, R., 2012, “Full-Range Stress-Strain Behaviour of Contemporary Pipeline Steels: Part I. Model Description,” Int. J. Press. Vess. Piping, 92, pp.34–40. [CrossRef]
Hertelé, S., Denys, R., and De Waele, W., 2009, “Full Range Stress-Strain Relation Modelling of Pipeline Steels,” J. Pipeline Eng., 8, pp.213–221.
Hertelé, S., Denys, R., and De Waele, W., 2009, “Full Range Stress-Strain Relation Modeling of Pipeline Steels,” Proceeding of the 5th International Conference on Pipeline Technology, Ostend, Belgium.
Hertelé, S., De Waele, W., and Denys, R., 2010, “Determination of Full Range Stress-Strain Behavior of Pipeline Steels Using Tensile Characteristics,” Proceedings of the 8th International Pipeline Conference, Calgary, Alberta, Canada, Paper No. IPC2010-31291.
Hertelé, S., De Waele, W., Denys, R., Van Wittenberghe, J., and Verstraete, M., 2010, “Investigation of Pipe Strain Measurements in a Curved Wide Plate Specimen,” Proceedings of the 8th International Pipeline Conference, Calgary, Alberta, Paper No. IPC2010-31292.
Fairchild, D. P., Cheng, W., Ford, S. J., Minnaar, K., Biery, N. E., Kumar, A., and Nissley, N. E., 2008, “Recent Advances in Curved Wide Plate Testing and Implications for Strain-Based Design,” Int. J. Offshore Polar Eng., 18, pp.161–170.
Shih, C. F., Moran, B., and Nakamura, T., 1986, “Energy Release Rate Along a Three-Dimensional Crack Front in a Thermally Stressed Body,” Int. J. Fract., 30, pp.79–102.
Rice, J. R., 1968, “A Path Independent Integral and the Approximate Analysis of Strain Concentration by Notches and Cracks,” J. Appl. Mech., 35, pp.379–386. [CrossRef]
Denys, R., Hertelé, S., Verstraete, M., and De Waele, W., 2011, “Strain Capacity Prediction for Strain-Based Pipeline Designs,” Proceedings of the International Workshop Welding High Strength Pipeline Steels, Araxá, Brazil.

Figures

Grahic Jump Location
Fig. 1

CWP specimen (Laboratory Soete)

Grahic Jump Location
Fig. 2

The Ramberg-Osgood equation predicts a unique relation between Y/T and em, which is not respected by experimental data [13]

Grahic Jump Location
Fig. 3

Example finite-element model of a half CWP specimen, with a focus on the spiderweb mesh near the defect tip

Grahic Jump Location
Fig. 4

Geometry of the CWP specimen's body, as recommended in the UGent guidelines [7]

Grahic Jump Location
Fig. 5

A cross section of the semielliptical weld root surface defect

Grahic Jump Location
Fig. 6

The girth weld is V-shaped and has excessive weld cap material

Grahic Jump Location
Fig. 7

CMOD, CTOD and J have been calculated (figure not to scale)

Grahic Jump Location
Fig. 8

Four LVDTs are used to deduce pipe strains [7]

Grahic Jump Location
Fig. 9

Example stress-strain relations used for the base metal (Y/T = 0.85)

Grahic Jump Location
Fig. 10

OMYS determines the CMOD response for limited (plastic) strains

Grahic Jump Location
Fig. 11

Weldments with an identical yield stress overmatch OMYS can fail differently

Grahic Jump Location
Fig. 12

As compared to OMYS (Fig. 10), OMTS is less suited to characterize the CMOD response of weldments for small plastic strains

Grahic Jump Location
Fig. 13

Ultimate tensile stress overmatch OMTS is a key factor governing the failure mode in absence of ductile crack growth

Grahic Jump Location
Fig. 14

In absence of stable or unstable crack growth, failure strain can be related to the uniform elongation of the base metal, em

Grahic Jump Location
Fig. 15

CMOD is not related to eo/em, for a fixed OMYS and OMTS

Grahic Jump Location
Fig. 16

Graphical representation of the UGent stress-strain model

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In