Spacing for simultaneous formation of dislocations

An estimate of the minimum value of p can also be obtained by following the approach adopted for calculation of the critical thickness condition in Section 6.2. According to this approach, it is necessary to compare the 

The value of = —Tj hh is unchanged from that in (6.45). The background stress which does work as each dislocation forms is still Tm and the displacement offset as a result of dislocation formation is still h. 

The calculation of is a bit more involved, but is again based on the fundamental expression 

For a given value of h, the minimum value that p can have for spontaneous dislocation formation is again established by the condition that Wd T = 0 or 

This condition also reduces to the critical thickness condition (7.1) as p/b 

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