The effect of characteristic crack sizes on the leak-before-break case of pressure vessels and piping with multiple cracks

The Leak-Before-Break (LBB) case of pressure vessels and piping is achieved with the sufficient margin between detectable leak and catastrophic break. Therefore, the respective characteristic crack sizes, i.e. leak size (the crack size at which leakage amount is great enough to be detected) and the break size (the crack size at which crack propagation becomes unstable) are two important governing parameters for the LBB case. In multiple crack sit uations, the initial crack distribution and crack coalescence behavior are also LBB governing factors. The multiple crack condition related parameters would affect the LBB margin with the characteristic crack sizes together. The effects of multiple cracks on the LBB case, with respect to the differe nt characteristic crack sizes are investigated in the present article by me ans of computer simulation. The simulation results show that, in multiple c rack situation, the LBB margin is not so sensitive to characteristic crack sizes as in single crack situation. (C) 1999 Elsevier Science Ltd. All righ ts reserved.