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This paper presents selected results on ductile crack propagation, curving and branching, and crack arrest from ten dynamic pipe rupture tests. Strain gage results adjacent to the crack path showed that a Dugdale-Barenblatt strip yield zone, of the order of eight pipe diameters in length, preceded the propagating crack tip and that the maximum principal strain direction changed from the hoop to the axial direction approximately 6 to 8 pipe diameters downstream of the crack tip. This change in principal strain direction constitutes the sufficiency condition for crack curving or branching prior to crack arrest in the absence of a crack arrester. The necessary condition for crack arrest is the sudden and sufficient increase in fracture resistance due to either increased apparent fracture toughness or a pipe opening restraint in the crack path.

The split-ring model is used to simulate full-scale pipe rupture experiments. Using experimentally measured pressures and pipe material characteristics, the model correctly predicts crack extension histories and depressurization rates. The model is also successful in predicting the occurrence of crack arrest and the arrest length.

The experimental facilities and the numerical modeling for studying dynamic axial rupture of pressurized subsize pipes are reviewed. Selected results from 46 pipe rupture tests and related numerical analyses are used to show that the axial flap stretching is the dominant energy sink, the crack tip opening angle (CTOA) is a viable ductile crack extension criterion, and there exists a crack tip strain field which promotes crack curving at arrest.

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