PSI - Issue 47

Mikhail Perelmuter / Procedia Structural Integrity 47 (2023) 545–551 M. Perelmuter / Structural Integrity Procedia 00 (2023) 000–000

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Fig. 5. The crack opening along crack bridged (healing) zone, d /ℓ = 0 . 5, c 0 = 0 . 1.

Fig. 6. Bonds tension along crack bridged (healing) zone, d /ℓ = 0 . 5, c 0 = 0 . 1.

Fig. 8. The stress intensity factors module vs time, d /ℓ = 0 . 5.

Fig. 7. The bond tension at the bridged zone edge vs time, d /ℓ = 0 . 5.

The crack opening along the bridged zone u / u 0 ( u 0 is the crack opening in the centre of the interface crack the same length without bonds, England (1965)) for several healing steps is shown in Fig. 5. Because bonds compliance decreases with healing steps (or bonds sti ff ness increases) therefore the crack opening in the bridged zone decreases according to relation (5). Noted, if time step number is greater i = 60 the convergence rate slows down. On the healing steps due to bonds formation and the increasing bonds sti ff ness the tension of bonds also increases (see Fig. 6). On the final healing step the bonds tension distribution similar to the undamaged crack with the same bridged zone and bond sti ff ness, see Goldstein and Perelmuter (1999). The compliance of the crack healed part in this model is defined by relative compliance parameter c 0 (see rela tion (9)) which define for linear-elastic bonds the stress state and SIFs in the bridged zone. Dependence on time of bonds tension at the bridged zone edge for di ff erent values of bonds relative compliance is shown in Fig. 7. With the decreasing the bond relative compliance the edge bonds tension is increased considerably. The final stress intensity factor modulus (after healing) is bigger if the bond relative compliance bigger. Also the total healing time is increased if the relative bonds compliance is decreased (see Fig. 8). It should be noted, that for all presented results the limit value of bonds was kept as N cr = 0 . 95 n 0 and the healing time variation is due to the relative compliance variation.