Stability of crack advance

Fig. 4.10. The variation of total potential energy and crack surface fracture energy with crack length is illustrated qualitatively for the configuration depicted in Figure 4.9 for the cases of (a) imposed boundary displacement 6 and (b) imposed boundary force P. The results illustrate the stability of crack advance under increasing displacement in case (a) and instability under increasing force in case (b). Adapted from Freund (1990).

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