Issue 33

L. Malíková et alii, Frattura ed Integrità Strutturale, 33 (2015) 25-32; DOI: 10.3221/IGF-ESIS.33.04

 Prediction of the crack propagation angle by means of one or two terms of the WE is accurate enough if the distance from the crack tip is small enough (let's say up to r c = 0.4 mm). The deviations from the numerical solution increase with larger distances.

= 0.2

= 0.4

= 1.0

= 1.5

= 1.8

= 3.2

r

r

r

r

r

r

c

c

c

c

c

c

-30

-50

e W / = 0.0

-70

0

-20

[deg.]

-40

e W / = 0.1

-60

-10

-30

e W / = 0.2

-50

-40 -30 -20 -10 0

e W / = 0.3

crack propagation direction angle

-40 -30 -20 -10 0 0.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5 1.0 N M = = 10 FEM Figure 3 : Dependences of the initial crack propagation direction angle γ on the relative crack length  for various relative crack eccentricities e / W obtained from the SED fracture criterion at various radial distances from the crack tip r c ; the purely numerical results ("FEM") are compared to the semi-analytical results (" N = M = 1, 2, 4, 7 and 10") calculated via the multi-parameter form of the fracture criterion. 3) SED fracture criterion, Fig. 3:  The dependences of the kink angle calculated via FEM behave more stably, value of the angle doesn’t change so much as when the MTS criterion is applied. relative crack length [-] N M = = 1 N M = = 2 N M = = 4 N M = = 7

e W / = 0.4

30