Fatigue Crack Paths 2003

C O N C L U S I O N S

1. Under random torsion and combined bending with torsion for stress ratio λσ=0.97

and near to zero correlation between normal and shear stresses rσ= -0.01, two fatigue

crack directions have been observed from which one of them is dominated.

2. The cross correlation coefficient between bending and torsion rσhas great influence

on the fatigue fracture plane position.

3. The position of fatigue fracture plane can be successfully established with use of

suitable weight functions based on stress or energy parameters.

4. For most of the loading the calculated fatigue fracture plane positions with use of the

weight functions W2and W3 agree with experimental ones very well.

R E F E R E N C E S

[1]

Findley, W.N. (1959) A theory for the effect of mean stress on fatigue of metals

under combined torsion and axial load or bending. Journal of Engineering for

Industry, 301-306.

[2]

Munday, E.G. (1992) Significance of the relative orientation of the mean and

alternating principal stress axes in biaxial fatigue. Transaction of ASME,Journal

of Engineering Materials and Technology, 114, 406-408.

[3]

Macha, E. (1989) Simulation investigations of the position of fatigue plane in

materials with biaxial loads. Material-wissenschaft und Werkstofftechnik 20, 132

136 and 153-163.

[4]

Carpinteri, A., Macha, E., Brighenti, R., Spagnoli A. (1999) Expected principal

stress directions under multiaxial random loading. Part I: Theoretical aspects of

the weight function method. Int. J. Fatigue 21, 83-88.

[5]

Carpinteri, A., Macha, E., Brighenti, R., Spagnoli, A. (1999) Expected principal

stress directions under multiaxial random loading. Part II: Numerical simulation

and experimental assessment through the weight function method. Int. J. Fatigue

21, 89-96.

[6]

Carpinteri, A., Karolczuk, A., Macha, E., Vantadori, S. (2002) Expected position

of the fatigue fracture plane by using the weighted mean principal Euler angles.

International Journal of Fracture 115, 87-99.

[7]

Carpinteri, A., Brighenti, R., Spagnoli, A. (1999) A fracture plane approach in

multiaxial high-cycle fatigue of metals. Fatigue Fract. Engng. Mater. Struct. 23,

355-364.

[8]

Korn, G.A., Korn, T.M. (1968) Mathematical Handbook. 2nd ed. N e w York:

McGraw-Hill Book Company.

[9]

£agoda, T., Macha, E., Bê dkowski, W. (1999) A critical plane approach based on

energy concepts: Application to biaxial random tension-compression high-cycle

fatigue regime. Int. J. Fatigue 21, 431-443.

With the support of the Commission of the European Communities under the FP5, G R O W T H

Programme, contract No. G1MA-CT-2002-0405(8CESTI)