Fatigue Failure of Structural Steel – Analysis Using Fracture Mechanics

Authors: Shine U P, EMS Nair

Abstract:

Fatigue is the major threat in service of steel structure subjected to fluctuating loads. With the additional effect of corrosion and presence of weld joints the fatigue failure may become more critical in structural steel. One of the apt examples of such structural is the sailing ship. This is experiencing a constant stress due to floating and a pulsating bending load due to the waves. This paper describes an attempt to verify theory of fatigue in fracture mechanics approach with experimentation to determine the constants of crack growth curve. For this, specimen is prepared from the ship building steel and it is subjected to a pulsating bending load with a known defect. Fatigue crack and its nature is observed in this experiment. Application of fracture mechanics approach in fatigue with a simple practical experiment is conducted and constants of crack growth equation are investigated.

Keywords: fatigue, fracture mechanics, fatigue testing machine

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1057073

References:

[1] C E Inglis, "Stress in a plate due to the presence of cracks and sharp corners," Trans. Institution of Naval Architects 55,219-242 (1913)
[2] A.A.Griffith, "The phenomena of rupture and flow in solids," Linear Networks and Systems (Book style). Belmont, CA: Wadsworth, 1993, pp. 123-135.
[3] Paris and Erdogan, 1963. "A critical Analysis of Crack Propagation Laws", Journ. Basic, Engg. pp., 528-534.
[4] Jaap Schijve, 2001, "Fatigue of Structures and Materials", Kluwer Academic Publishers, Printed in the Netherlands
[5] Alexander Blake, 1996. "Practical Fracture Mechanics in Design", Marcel Dekker, Inc. USA.
[6] David Broek, 1986. "Elementary Engineering Fracture Mechanics", Chapter 2, 10, Kluwer academic Publishers, Dordrecht.
[7] G G Chell, Edited 1979. "Developments in Fracture Mechanics", Vol.1&11, Applied Science Publishers Ltd., London.
[8] Compendium UK 2006-93 Faulty of engineering science and technology Ntnu Trondheim Norwegian Univeristy of science and technology
[9] Short Term Course, "Fatigue Design and analysis of Ships and Offshore structures" Ocean Engg. Dept., IIT Madras. Feb. 2007