Probability of onset of brittle failure of vessels under pressure

Conclusions

The method proposed for determining the failure probability of pressurized vessels offers the possibility of quantitative comparison of the safety of different vessels in different operating conditions and estimating their failure probability overall. It may be further developed by replacing determinate characteristics by random characteristics. For example, that q is determinate in Eq. (1) means that the orientation of all the defects in the vessel relative to the largest principal stress is strictly constant. In practice, this means that q must be taken for the defect orientation which is worst from the viewpoint of strength; this makes the method excessively conservative. This may be eliminated if the probability density function of the crack orientation in space is introduced and used to calculate the distribution of values of the random parameter q.