Crack Paths 2009

β

+ ∆ =

k σ τ

(A2)

Find

nmax

incorporates the peak opening stress σnmax, computed along the facet which undergoes

∆τ. Figure A1b shows the measured fatigue lives in

the maximumshear stress range,

reversed torsion with various static tensile stresses as a function of βSWT in which k=0.2

gave the best correlation. There again an exponential fit was obtained.

5

10

1000000

b)

a)

100000

4

10

10000

1000

y=2E+27x-7,622

1000

R2=0,9807

y =1,672e+0*7x^(-2,9937) R =0,9962

100

100

1000

10000

100 1

10

100

σ ε

β

S W T ∆ =

n

m a x n

max,n.20Findσ+τ∆=β

Figure A1: Fit of a) Smith, Watson and Topper’s fatigue criterion from tensile fatigue

data and b) Findley’s criterion from reversed torsion + static tension data.

Acknowledgments : This study was supported by the Agence Nationale de la Recherche

R E F E R E N C E S

1. Pinna C., Doquet V. (1999), Fat. Fract. Eng. Mat. Struct 22, 173-183.

2. Findley W.N.(1957), Trans A S M E79, 1337–1348.

3. Smith K.N., Watson P. and Topper T.H. (1970), Journal ofmaterials 5, 767-778.

4. Erdogan F., Ratwani M. (1972), Int. Journ. Fract. Mech 8, 87-95.

5. Doquet V., PommierS. (2004), Fat. Fract. Eng. Mat. Struct 27, 1051-1060.

6. Hourlier F., d’Hondt H., Truchon M., Pineau A. (1985), Multiaxial Fatigue, A S T M

STP 853, KJ Miller and M WBrown eds, ASTM,Philadelphia, 228-248.

7. Dahlin P., Olsson M. (2003), Fat. Fract. Eng. Mat. Struct 26, 577-588.

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