PSI - Issue 39

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Daniele Amato et al. / Procedia Structural Integrity 39 (2022) 582–598 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Finally, specimens 0_1_90_3 and 1_1_90_3 ( = 0.76 ) presented a crack surface flat on average with waves at both free surfaces. Therefore, in all cases with a phase shift of 90° , determining a deflection angle is difficult and not very reliable. To sum up, the results of all these tests were ambiguous (for a high torsion/tension ratio) or tended to very low kink angles (for a low torsion/tension ratio). Figure 13 Three different experimental crack surfaces for loading conditions 1_1_90_1.

Figure 14 Experimental result: (a) 0_1_90_2 specimen; (b) 1_1_90_2 specimen.

6. Conclusions In this study, a numerical simulation procedure was proposed to analyse the cases of cyclic non-proportional, mixed-mode missions. The numerical crack growth analyses were carried out by means of both the FE software, ABAQUS and FRANC3D. In order to assess the algorithms used within the simulation process in predicting the crack growth direction, the simulated crack surfaces were validated with experimental tests.