Crack Paths 2012

m/cycle ]

2

m/cycle ]

2

1

1

th r a t e

0.5

ghrowt r a t e

0.5

gwro

0.2

R e f e r e n c e c r a c k

Const.

a c k

Const.

0.2

M e a n c r

0.1

Random

Random

199+1

0.1

0.05

199+1

0.002 0.05 Meanresidual major plastic zonesize 'w*m [mm] 0.005 0.01 0.02

0.002 0.02 0.05 Meanresidual major plastic zone size 'w*m [mm] 0.005 0.01

a

b

Fig. 6: Plot of the dependence between the local meansize of the residual major cyclic

and a) mean conventional crack growth rate v, b) reference

plastic zone

* m w '

crack growth rate vref. Thick lines represent mean dependences for each loading.

C O N C L U S I O N S

Utilizing 3D representation of a fracture surface improves possibilities of the textural

fractography. However, this method is not fully objective as we expected, because

various methods of 3D reconstruction provide quite different results. Simultaneously,

the price for this alternative to S E Mimages is a substantial increase of laboriousness.

Results obtained allow to argue that reference features are governed by cyclic

plasticity corresponding to the major values of the effective SIF range 'Kef. This fact

opens a way for investigation of the relation between physical parameters of crack

growth process and the mezoscopical dimensional component of the morphology of

fracture surface.

R E F E R E N C E S

1. Lauschmann, H., Siegl, J., Šiška, F., Šumbera, J. and Nedbal, I. (2006) Materials

Characterization 56 Iss. 4-5, 257-265.

2. Lauschmann, H., Goldsmith, N. (2009). In: Fatigue crack growth, pp. 125-166,

Lignelli, A.F. (Ed.), NovaScience Publishers Inc., N e wYork.

3. Sekerešová, Z. (2011). PhDThesis (in Czech). FNSPE,Czech Technical University

Republic.

in Prague, Czech

4. Lauschnmann, H., Šiška, F. (2012) Int. Journal of Fatigue (accepted).

Acknowledgement.This research was supported by the Ministry of Industry and Trade

of the Czech Republic, Project "Operational detector of fatigue damage of structural

parts using acoustic emission", No. FR - TI2/447.

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