Some research in the field of leak before break criteria for piping

Leak-before-break research activity has lead to the following basic results: a) From an extensive analysis of the available experimental data it is concluded that the concept of net section collapse is a simple, reliable, valid tool in the case of very ductile materials. b) The analysis of some experimental data has lead to the conclusion that for partially ductile materials mixed ductile, fragile conditions may be present. c) From the analyses at a and b criteria have been established in order to compute collapse conditions for through cracked pipes as a function of the applied load (moment and axial load) in terms of net section collapse. d) The role of the thermal and secondary self equilibrating loads is discussed. e) The leak areas are often evaluated on the basis of the 0.1 Aflow criterion, i.e. somewhat arbitrarily assuming a leak area equal to 10% the pipe flow area. f) The 0.1 Aflow criteria is applied to typical lines, and it is concluded that such loads can be taken without using the classical pipe whip restraints, even if some increase in the size of the snubbers might be necessary