Saturation matrix crack spacing

When d is sufficiently small, Eqn. (40a) applies and 3,ip is independent of the stress. Once this occurs,, ip cannot increase and is unable to satisfy again the matrix crack growth criterion (Eqn. (24)). This occurs with spacing, ds, at an associated stress as (Fig. 1.11). This saturation spacing is given by... 

As the stress is raised above the first matrix cracking stress, further cracking occurs resulting in a periodic crack array. Cao et al.55 have shown that the magnitude of the saturation crack spacing, d, is governed by the sliding stress, t, such that r and d are related by... 

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