The Influence of Chord Yield-to-Tensile Stress Ratio on the Static Strength of Unstiffened CHS K-Gap Joints under Static Axial Loading

Abstract:

The yield strength-to-tensile stress ratio (fy/fu) is considered to be an important material factor in the design of welded tubular joints. For instance CIDECT (2008) has set a limitation on fy of 0.8fu and for steels with nominal fy greater than 355Mpa and a reduction factor of 0.9 on all joint strength formulae to account for the relatively larger deformations that take place for joints with nominal fy of 450Mpa[1]. In this study a statistical analysis of an experimental database was carried in order to determine the influence of the chord fy/fu ratio on joint strength. A finite element study was also carried out in order to quantify this influence and a yield strength function was proposed. Results from the statistical analysis and finite element study both show that the static strength of unstiffened circular hollow section (CHS) K-gap joints under static axial loading is inversely proportional to the chord fy/fu ratio.

• Periodical: Applied Mechanics and Materials (Volumes 204-208)
• Pages: 4702-4715
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.204-208.4702
• Online since: October 2012
• Authors: Chisanga Kaluba, M. Mulife Tawana
• Keywords: CHS K-Gap Joint, Database, Finite Element Analysis (FEA), Yield Strength-Tensile Stress Ratio

References

[1] Kurobane, Y., Packer, J.A., van der Vegte, G.J., Wardenier, J. and Zhao, X.L., CIDECT Design Guide 7 For Circular Hollow Section (CHS) Joints Under Predominantly Static Loading, second ed., 2nd ed, 2008, p.11, p.33

DOI: 10.1201/9780203882818.ch29

[2] Wardenier, J.,. Hollow sections in structural applications. CIDECT (2000). p.2.6

[3] Bannister, A.C. Gutierrez-solana, F. and Ocejo, J.R., Implications of the yield stress/tensile stress ratio to the SINTAP failure assessment diagrams for homogeneous materials. Engineering Fracture Mechanics, 67 (2000) 547-562, p.1

DOI: 10.1016/s0013-7944(00)00073-4

[4] Health and Safety Executive, Review of the performance of high strength steels used offshore. [pdf] Sudbury: Health and Safety Executive (2003). Available at: <http://www.hse.gov.uk/research/rrpdf/rr105.pdf> [Accessed 1 June 2011].

[5] Kurobane, Y.. New developments and practices in tubular joint design. IIW Doc. XV-488-81 and IIW Doc. XIII-1004-81, 1981, pp.7-8.

[6] Packer, J.A., van der Vegte, G.J., Wardenier, J. and Zhao, X.L., Background of the new RHS joint strength equations in the IIW (2009) recommendations. Tubular Structures XIII, 2010., pp.403-405

DOI: 10.1201/b10564-56

[7] Health and Safety Executive, Static Strength of High Strength Steel Tubular Joints. [pdf] Sudbury: Health and Safety Executive (1999). Available at: < http://www.hse.gov.uk/research/othpdf/500-599/oth562.pdf > [Accessed 19 July 2012].

[8] Makino, Y., Kurobane, Y., Ochi, K., van der Vegte, G. J. and Wilmshurst, S.R., Database of Test and Numerical Analysis Results for Unstiffened Tubular Joints, IIW Doc XV -E-96-220, Kumamoto University, Kumamoto, 1996.

DOI: 10.1201/9780203735008-25

[9] Fleischer, O., Herion, S. and Puthli, R, Numerical investigation on the static behavior of CHS X-joints made of high strength steels. Tubular Structures XII, 2009, pp.598-599

DOI: 10.1201/9780203882818.ch68

[10] Kurobane, Y. and Ochi, K., AWS vs International Design Rules for circular tubular K-connections. Engineering Structures, 19, pp.259-266 (1996) pp.260-261.

DOI: 10.1016/s0141-0296(96)00101-0

[11] Wardenier, J., van der Vegte, G.J., Makino, Y., and Marshall, P.W., Comparison of the new IIW (2008) CHS joint strength formulae with those of the previous IIW (1989) and the new API (2007), Tubular Structures XII (2009), p.282.

DOI: 10.1201/9780203882818.ch31

[12] Lee, M.M., Strength, stress and fracture analyses of offshore tubular joints using finite elements, Journal of Constructional Steel Research, vol 51 (1999), p.270.

DOI: 10.1016/s0143-974x(99)00025-5