Advanced Steel Construction

Vol. 4, No. 3, pp. 210-229 (2008)


ASSESSMENT OF CYCLIC DUCTILE ENDURANCE OF STRUCTURAL STEEL MEMBERS

 

C.W.K. Hyland 1,*, W.G. Ferguson 2 and J.W. Butterworth 3

1 Secretary Manager, Steel Construction New Zealand Inc., PO Box 76403, Manukau City 2241, New Zealand

Phone: +64-9-262-6680 Fax: +64-9-263-5638

*(Corresponding author: E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.)

2 Professor of Chemical & Materials Engineering, University of Auckland, Private Bag 92019, Auckland 1061, New Zealand

Phone: +64-9-373-7599 Ext 88133 Fax: +64-9-373-7463

3 Associate Professor of Civil and Environmental Engineering, University of Auckland, Private Bag 92019, Auckland 1061, New Zealand

Phone: +64-9-373-7599 Ext 88154 Fax: +64-9-373-7462

Received: 4 May 2007; Revised: 31 August 2007; Accepted: 18 September 2007

 

DOI:10.18057/IJASC.2008.4.3.4

 

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ABSTRACT

  This paper describes a new method using Crack Tip Opening Displacement (CTOD) testing in conjunction with a relatively simple elasto-plastic finite element analysis to assess the likelihood of fast running or slow stable fracture during monotonic and cyclic loading of steel members.  The similitude relationship between monotonic and cyclic displacement ductility is then used to assess cyclic endurance of the steel member. The fracture toughness of steel defined by the critical specific work of fracture Rc of the steel is determined from CTOD specimens making allowance for remote plastic flow. A finiteelement model is used to assess elastic compliance of a cracked bar with varying lengths of cracks as well as to assess the inelastic displacement of the bar at calculated cracking loads.   Failure limit state surfaces comprising plastic hinging, plastic over-strength and cracking limits are plotted in 3-D surfaces to identify the characteristics of how fracture behaviour changes dramatically as the strain hardening and crack length increases.

 

KEYWORDS

Specific work of fracture, fracture toughness, structural ductility, cyclic endurance, seismic, finite element analysis, CTOD


REFERENCES

[1]      Hyland, C.W.K., Ferguson, W.G. and Butterworth, J.W., “Effects of Pre-strain and Aging on the Fracture Toughness of Australasian Constructional Mild Steel”, Proceedings of Structural Integrity and Fracture 2004, Brisbane, 2004.

[2]      Atkins, A.G. and Mai, Y.-W., “Elastic and Plastic Fracture: Metals, Polymers, Ceramics, Composites, Biological Materials”, Ellis Horwood Limited, Chichester, 1985.

[3]      Kuwamura, H., and Takagi, N., “Similitude Law of Prefracture Hysteresis of Steel Members”, Journal of Structural Engineering, Vol. 130, No. 5, pp. 752-761, 2004.

[4]      Knott, J.F., “Fundamentals of Fracture Mechanics”, Cambridge University, 1973.

[5]      Standards New Zealand, “Structural Loadings Standard: Earthquake”, NZS1170.5, Wellington, 2005.