Tests to Determine Stress Concentration Factors for Square Bird-Beak SHS Joints under Chord and Brace Axial Forces
Publication: Journal of Structural Engineering
Volume 140, Issue 11
Abstract
Bird-beak joints are a type of welded square hollow section (SHS) joint, the static strength of which is higher than that of conventional joints. Experimental analyses were conducted on the stress concentration factors (SCFs) of square bird-beak joints to obtain more information regarding their fatigue behavior. Twelve specimens, i.e., three conventional joints and nine square bird-beak joints, are separately tested by considering chord and brace axial force load cases. Both conventional and square bird-beak joints tested have a T-shape and are simply supported at their chord ends. Elastic strain distributions near the crown and saddle areas are measured, and strain concentration factors (SNCFs) at potential hot spots are calculated using an extrapolation approach. Quadratic extrapolation is suggested for the square bird-beak joints because linear extrapolation may underestimate SNCFs by up to 35%. Furthermore, critical locations are identified for square bird-beak joints subjected to chord and brace axial forces. A comparison indicates that the square bird-beak joints can produce lower stress concentration factors than the conventional or the diamond bird-beak joints with identical nondimensional parameters, especially when brace-to-chord width ratios are relatively small.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The research reported in this paper was undertaken with support from the Science and Technology Research and Development Plan funded by the Ministry of Railway of the People’s Republic of China (P.R.C., No. J2011G002).
References
Ansys 12 [Computer software].
Chiew, S. P., Lee, C. K., Lie, S. T., and Ji, H. L. (2007). “Fatigue behaviors of square-to-square hollow section T-joint with corner crack. I: Experimental studies.” Eng. Fract. Mech., 74(5), 703–720.
Chtistitas, A. D., Pachoumis, D. T., Kalfas, C. N., and Galoussis, E. G. (2007). “FEM analysis of conventional and square bird-beak SHS joint subjected to in-plane bending moment–Experimental study.” J. Constr. Steel Res., 63(10), 1361–1372.
Davies, G., Owen, J. S., and Kelly, R. (1996). “Bird beak T-joints in square hollow sections: A finite element investigation.” Proc., Int. Offshore and Polar Engineering Conf., Int. Soc. of Offshore and Polar Engineers, Mountain View, CA, 1–6.
International Institute of Welding (IIW). (2008). Recommended fatigue design procedure for welded hollow section joints-part 1: Recommendations, part 2: Commentary, XV-1035-99, Cedex, France.
Ishida, K. (1992). “Experimental research on fatigue behavior of diamond bird-beak joint.” Proc., Symp. on Structural Engineering, Architectural Institute of Japan, Tokyo (in Japanese).
Ishida, K., Ono, T., and Iwata, M. (1993). “Ultimate strength formula for joints of new truss system using rectangular hollow sections.” Proc., Int. Symp. on Tubular Structures, E&FN Spon, London, 511–518.
Keizer, R. (2003). “Stress concentration factors in diamond bird beak T-joints.” M.S. Thesis, Delft Univ. of Technology, Delft, Netherlands.
Keizer, R., Romeijn, A., and Wardenier, J. (2003). “The fatigue behaviour of diamond bird beak T-joints.” Proc., Int. Symp. on Tubular Structures, Vol. 10, M. A. Jaurietta, et al., eds., E&FN Spon, London, 303–310.
Lei, L. Y. (2009). “The analysis of square bird-beak SHS joint subject to in-plane bending moment.” M.S. thesis, Xi’an Univ. of Architecture and Technology, Xi’an, China.
National Standards for the People’s Republic of China. (2002). “Cold formed steel hollow sections for general structure-dimensions, shapes, weight and permissible deviation.”, Beijing.
Ono, T., Iwata, M., and Ishida, K. (1991). “An experimental study on joints of new truss system using rectangular hollow sections.” Proc., Int. Symp. on Tubular Structures, E&FN Spon, London, 344–353.
Ono, T., Iwata, M., and Ishida, K. (1993). “Local failure of joints of new truss system using rectangular hollow sections subjected to in-plane bending moment.” Proc., Int. Symp. on Tubular Structures, E&FN Spon, London, 503–510.
Ono, T., Iwata, M., and Ishida, K. (1994). “Local failure of joints of new truss system using rectangular hollow sections subjected to out-of-plane bending moment.” Proc., Int. Symp. on Tubular Structures, E&FN Spon, London, 441–448.
Owen, J. S., Davies, G., and Kelly, R. B. (1996). “A comparison of the behaviour of RHS bird beak T-joints with normal RHS and CHS systems.” Proc., Int. Symp. on Tubular Structures, E&FN Spon, London, 173–180.
Owen, J. S., Davies, G., and Kelly, R. B. (2001). “The influence of member orientation on the resistance of cross joints in square RHS construction.” J. Constr. Steel Res., 57(3), 253–278.
Owen, J. S., and Kelly, R. B. (2001). “The effect of purlin loads on the capacity of overlapped bird-beak K joints.” Proc., Int. Symp. and Euroconf., CRC, Boca Raton, FL, 229–238.
Packer, J. A., and Wardenier, J. (1998). “Stress concentration factors for non-90° X-connections made of square hollow sections.” Can. J. Civ. Eng., 25(2), 370–375.
Tong, L. W., Fu, Y. G., Liu, Y. Q., and Zhao, X. L. (2014). “Stress concentration factors of diamond bird-beak SHS T-joints under brace loading.” Thin Walled Struct., 74(1), 201–212.
van Wingerde, A. M. (1992). “The fatigue behaviour of T- and X-joint made of square hollow section.” HERON, 37(2), 1–180.
van Wingerde, A. M., Packer, J. A., and Wardenier, J. (1997). “SCF formulae for fatigue design of K-connections between square hollow sections.” J. Constr. Steel Res., 43(1), 87–118.
Wardenier, J., Packer, J. A., Zhao, X. L., and van der Vegte, G. J. (2010). Hollow sections in structural applications, Comité International pour le Développement et l’Etude de la Construction Tubulaire, Bouwen met Staal, Zoetermeer, Netherlands.
Zhao, X.-L., et al. (2000). “Design guide for circular and rectangular hollow section joints under fatigue loading.” Comité International pour le Développement et l’Etude de la Construction Tubulaire, TÜV-Verlag, Köln, Germany.
Zhu, Z. Q., and Liu, S. L. (2012). “Nonlinear finite element analysis of diamond bird-beak TX-joints.” Adv. Mater. Res., 446(1), 151–155.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 140 • Issue 11 • November 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Nov 22, 2013
Accepted: Apr 7, 2014
Published online: May 29, 2014
Discussion open until: Oct 29, 2014
Published in print: Nov 1, 2014
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.