Issue 33

L. Malíková et alii, Frattura ed Integrità Strutturale, 33 (2015) 25-32; DOI: 10.3221/IGF-ESIS.33.04 29 -70 -50 -30 -60 -40 -20 0 -50 -30 -10 -40 -30 -20 -10 0 -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 e W / = 0.0 e W / = 0.1 e W / = 0.2 e W / = 0.3 e W / = 0.4 r c = 0.2 r c = 0.4 r c = 1.0 r c = 1.5 r c = 1.8 r c = 3.2 crack propagation direction angle [deg.] relative crack length [-] N M = = 1 N M = = 2 N M = = 4 N M = = 7 N M = = 10 FEM Figure 2 : Dependences of the initial crack propagation direction angle γ on the relative crack length  for various relative crack eccentricities e / W obtained from the MTS 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. 2) MTS fracture criterion, Fig. 2:  Whereas the dependences of the kink angle calculated via FEM fluctuate at several points, the results obtained by means of the WE approximation seems to be more stable.  The kink angle dependence calculated via FEM is changing with increasing r c and this phenomenon can be well described by means of the multi-parameter form of the fracture criterion; N = M = 4 is sufficient up to r c = 1.5 mm, N = M  7 needs to be considered for larger distances from the crack tip.