Stress concentration factors and fatigue failure of welded T-connections in circular hollow sections under in-plane bending

Fidelis Rutendo Mashiri, Xiao Ling Zhao, Paul Grundy

Research output: Journal article publicationJournal articleAcademic researchpeer-review

28 Citations (Scopus)

Abstract

The fatigue behavior of welded thin-walled T-joints made up of both circular hollow section (CHS) braces and chords, subjected to cyclic in-plane bending, is described in this paper. CHS chords and braces are of thicknesses less than 4 mm. Current fatigue design guidelines show that the design of welded tubular nodal joints is restricted to thicknesses greater than or equal to 4 mm. The increased availability and use of thin-walled (t < 4 mm) tubes of high-strength steels in recent years, in structures subjected to cyclic loading, means that it is important to study the fatigue behavior of welded thin-walled tubular nodal joints. In this paper, welded thin-walled CHS-CHS T-joints subjected to constant-stress-amplitude cyclic in-plane bending range are studied. The stress concentration factors (SCFs) determined experimentally at the brace and chord crown positions are shown to be about 30% and 40% respectively of the SCFs determined using parametric equations in existing fatigue design guidelines. The fatigue tests showed that in welded thin-walled CHS-CHS T-joints, a through-thickness crack occurs when the surface crack length along the weld toes in the chord has grown to a length equal to about 40% of the circumference of the brace member. An end of test failure criterion was proposed as an alternative to the through-thickness failure criterion, in obtaining data that is suitable for determining fatigue design S-N curves.

Original languageEnglish
Pages (from-to)403-422
Number of pages20
JournalInternational Journal of Structural Stability and Dynamics
Volume4
Issue number3
DOIs
Publication statusPublished - Sept 2004
Externally publishedYes

Keywords

  • Crack growth
  • Fatigue failure
  • Steel tubes
  • Stress concentration factor

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Aerospace Engineering
  • Ocean Engineering
  • Mechanical Engineering
  • Applied Mathematics

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