Delayed Fracture under Constant Load

At this point, it will be beneficial to analyze the simple case of a test under constant load (with homogeneous and uniaxial stress state Ostat)- In Ais case, and for = 0, it can be shown that Eq. (23) becomes 

With Eq. (21) the dependence of the lifetime on initial crack size can be evaluated. It is  

The crack length at any given time under load (at constant stress) can be determined by integrating the crack growth rate over time. The result is  

SCCG exponent of alumina). The cracks need a large fraction of specimen lifetime to grow the first few percent they then accelerate, and fracture occurs very quickly. This behavior is promoted by high SCCG exponents. 

Of course, the scatter of data in both distributions is a result of the spedmen-to-specimen variation in the size of the critical flaw. Therefore, the time Weibull distribution can be deduced from the strength Weibull distribution [Eq. (12)] by taking SCCG into account. 

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Delayed Fracture under Increasing Load Constant Stress Rate Tests... 

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