Pipe segment failure dependency analysis and system failure probability estimation

The present paper is mainly concerned with pipe-system failure probability estimation. For this purpose, a multiple component dependent failure (MCDF) model is introduced to deal with dependency among pipe-segment failures. The MCDF model is directly derived from load–strength interference analysis with the underlying notion that stochastic environment load brings about failure dependency. The influence of pipe-segment failure dependency on pipe-system failure probability is addressed and a modified system failure probability model is presented. It is also shown that, with regard to a pipe system, the multiple failures of pipe-segment leaks might lead to a pipe-system disabling leak or even to a break. The probability of a pipe-system disabling leak or break induced by the simultaneous failures of multiple segment leaks is estimated by means of the MCDF model. The estimation results indicate that pipe-system failure probability depends not only on the mean values of the respective segment-failure probability random variables, but also on other distribution parameters (e.g., the standard deviations) of them. Pipe-system failure probability estimated by means of the modified model is sometimes several times lower than that estimated by the conventional system failure probability model.