The Mechanism of Fatigue Crack Propagation


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As a retardation of fatigue crack propagation occur under two step loading such as high to low loading, it is difficult to predictt the fatigue life in variable loading conditions. Therefore, the mechanism of retardation was investigated by changing the ratio of two step-loading in some materials in this paper. It is found in this study that when the ratio of low loading to high loading is less than 50 %, crack arrest occur in agreement with Elber’s formula about crack closure. We believe that crack closure phenomenon is the main problem in considering mechanism of crack propagation in the second stage. In this paper it is estimated that crack closure phenomenon arises because tensile plastic zone at crack tip is compressed by surrounding elastic zone. On the basis of the crack closure phenomenon, the mechanism of crack propagation in the second stage is proposed.



Key Engineering Materials (Volumes 345-346)

Edited by:

S.W. Nam, Y.W. Chang, S.B. Lee and N.J. Kim




K. Furukawa, "The Mechanism of Fatigue Crack Propagation", Key Engineering Materials, Vols. 345-346, pp. 231-234, 2007

Online since:

August 2007




[1] W. Elber, The significance of fatigue crack closure, ASTM STP 486, pp.230-242 (1971).

[2] H. Sehitoglu and D. L. McDiarmid , The effect of load step-down on fatigue crack arrest and retardation, International Journal of Fatigue, April, pp.55-60 (1980).


[3] D. L. McDiarmid, W. Choy and T.M. Lee, The effect of mean stress on delay in fatigue crack growth under load step-down, International Journal of Fatigue, Vol. 6, No. 2, April, pp.101-105(1984).


[4] D. Damri and J. F. Knott, Fatigue crack growth retardation in plane stress and plane strain, Journal of Materials Science, Vol. 26, pp.5613-5617 (1991).


[5] J. C. Newman Jr., A. Brot and C. Matias, Crack-growth calculations in 7075-T7351 aluminum alloy under various load spectra using an improved crack-closure model, Engineering Fracture Mechanics, Vol. 71, pp.2347-2363 (2004).


[6] Ravindra Patankar and Asok Ray, State-space modeling of fatigue crack growth in ductile alloys, Engineering Fracture Mechanics, Vol. 66, pp.129-151 (2000).