Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components

Martin Muscat, Kevin Degiorgio, James Wood

Research output: Contribution to conferencePaper

Abstract

Fatigue cracks in welds often occur at the toe of a weld where stresses are difficult to calculate at the design stage. To circumvent this problem the ASME Boiler and PV code Section VIII Division 2 Part 5 [1] uses the structural stress normal to the expected crack to predict fatigue life using elastic analysis and as welded fatigue curves. The European Unfired Pressure Vessel Code [2] uses a similar approach. The structural stress excludes the notch stress at the weld toe itself. The predicted fatigue life has a strong dependency on the calculated value of structural stress. This emphasizes the importance of having a unique and robust way of extracting the structural stress from elastic finite element results. Different methods are available for the computation of the structural hotspotstress at welded joints. These are based on the extrapolation of surface stresses close to the weld toe, on the linearisation of stresses in the through-thickness direction or on the equilibrium of nodal forces. This paper takes a critical view on the various methods and investigates the effects of the mesh quality on the value of the structural stress. T-shaped welded plates under bending are considered as a means for illustration.
LanguageEnglish
Pages231-240
Publication statusPublished - 26 Jul 2009
EventASME Pressure Vessels and Piping Conference - Prague, Czech Republic
Duration: 26 Jul 200930 Jul 2009

Conference

ConferenceASME Pressure Vessels and Piping Conference
CityPrague, Czech Republic
Period26/07/0930/07/09

Fingerprint

Pressure vessels
Welds
Fatigue of materials
Pressure vessel codes
Linearization
Extrapolation
Boilers
Cracks

Keywords

  • structural stress
  • welded pressure
  • vessel components
  • welding
  • piping

Cite this

Muscat, M., Degiorgio, K., & Wood, J. (2009). Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components. 231-240. Paper presented at ASME Pressure Vessels and Piping Conference, Prague, Czech Republic, .
Muscat, Martin ; Degiorgio, Kevin ; Wood, James. / Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components. Paper presented at ASME Pressure Vessels and Piping Conference, Prague, Czech Republic, .
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Muscat, M, Degiorgio, K & Wood, J 2009, 'Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components' Paper presented at ASME Pressure Vessels and Piping Conference, Prague, Czech Republic, 26/07/09 - 30/07/09, pp. 231-240.

Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components. / Muscat, Martin; Degiorgio, Kevin; Wood, James.

2009. 231-240 Paper presented at ASME Pressure Vessels and Piping Conference, Prague, Czech Republic, .

Research output: Contribution to conferencePaper

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Muscat M, Degiorgio K, Wood J. Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components. 2009. Paper presented at ASME Pressure Vessels and Piping Conference, Prague, Czech Republic, .