A Study On Failure Stress and Fatigue Crack Rate Implemented to a Double Edge Notched Gusset Plate
DOI:
https://doi.org/10.5614/jts.2023.30.2.18Keywords:
Fracture mechanics, fatigue loading, stress intensity, double-edge notchedAbstract
Abstract
A gusset plate is a member of a bridge structure that is significantly subjected to cyclically varying loads. It may collapse after a certain number of cycles. However a single cycle may causes structural failure although the maximum stress (due to loading) is much less than the yield or the ultimate stress of the material. In a case of notched component under such conditions, high-intensity stress will occur at the zone of the notched component. Fracture mechanics is strongly recommended in a bridge design especially for joints. It will determine the moment at which fatigue cracks will occur and how far it has propagated. This study explores a fracture phenomenon of a steel gusset plate due to fatigue loading. Modeled as a double-edged notched plate, the failure stress is found to be less than the ultimate stress of the material. By assuming that crack closure exist, the results of this study provide a significant conclusion: under a constant failure stress the rate of fatigue growth increases as the crack propagates.
Keywords: Fracture mechanics, fatigue loading, stress intensity, double-edge notched
References
ASTM E647, ?Standard Test Method for Measurement of Fatigue Crack Growth Rates?, Annual Book of ASTM Standards, Section 3, Volume 03.01,1996.
Broek, D., Elementary Engineering Fracture Mechanics, 4th rev. ed., MartinusNijhoff, Dordrecht, 1986.
David Roylance, ?Mechanics of Materials?, New York: John Wiley & Sons, Inc, 1996.
H. L. Ewalds, R. J. H. Wanhill, ?Fracture Mechanics?, Edward Arnold: Delftse Uitgevers Maatschappij, 1984.
J. F. Throop, and G. A. Miller, ?Optimum Fatigue Crack Resistance,? in Achievement of High Fatigue Resistance in Metals and Alloys, ASTM STP 467, American Society for Testing and Materials, Philadelphia, p.154, 1970.
J. M. Barsom, ?Fatigue-Crack Propagation in Steels of Various Yield Strengths,? Trans. ASME, J. Eng. Ind., Vol. B73, No. 4, p.154, 1971.
Julie A. Bannantine, Jess J Comer, James L. Handrock, ?Fundamentals of Metal Fatigues Analysis?, Englewood Cliffs, New Jersey 07632: Prentice Hall, 1990.
P. C. Paris, and F. Erdogan, ?A Critical Analysis of Crack Propagation Laws,? Trans ASME, J. Basic Eng., vol. D85, pp. 528-5 34, 1963.
Surendra P. Shah, E. Swartz, Chengsheng Ouyang, ?Fracture Mechanics of Concrete?, John Wiley & Sons, Inc, 1995.
W. Elber, ?The Significance of Fatigue Crac Closure, ?in Damage Tolerancen Aircraft Structures,ASTM STP 486, American Society for Testing and Materials, Philadelphia, pp.230-242, 1971.
