Characterization of the Stable Tearing During Pipeline Strain Capacity Tests

摘要

ExxonMobil has developed a methodology to predict the strain capacity of welded pipelines based on tearing analysis. However it has not been fully established by the industry that accounting for tearing is important for an accurate prediction of strain capacity. To that end ExxonMobil has performed a series of full-scale tests using an unloading compliance technique to measure crack extension. Final flaw sizes are measured on opened fracture surfaces confirming unloading compliance accuracy. Test results show tearing initiation long before the final strain capacity suggesting that not accounting for tearing may lead to unnecessary conservatism.