PSI - Issue 23

Vera Petrova et al. / Procedia Structural Integrity 23 (2019) 407–412 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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c d Fig. 2. The SIFs k I and k II as functions of β for different distances d between the edge cracks; results are for the cracks: (a) for an edge crack 1 with half-length a 1 ; (b) for an internal crack 4 with half-length a 4 =0.5 a 1 , and (c) and (d) for edge cracks 2 and 3 with half-lengths a 2 = a 3 =0.5 a 1 .

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Fig. 3. The fracture angles ϕ as functions of β for different distances d between the edge cracks; results are for the cracks: (a) for an edge crack 1 with half-length a 1 ; (b) for an edge crack 2 with half-length a 2 =0.5 a 1 . Fracture angles ϕ for three edge cracks with inclination angles (c) β =60  and (d) β =90  and for distances d = 2, 4 and 6. The SIFs k I,II and fracture angles ϕ for cracks 2 and 3 are affected by the distance between them ( d/a ), in contrast to the fracture characteristics for cracks 1 and 4, Figs. 2 and 3a,b. A strong influence of the interaction of the edge crack 1 with internal crack 4 on the fracture characteristics is observed, Fig. 2. The investigation of critical loads (not shown here) reveals that crack 1 has the maximum value of critical load for angles β close to 90  (due to the influence of the internal crack), i.e. the crack 1 will not propagate; the internal crack starts first.