EFFECT OF STRESS-STRAIN CURVE ON BURST PRESSURE PREDICTION FOR PIPELINES WITH AND WITHOUT CORROSION DEFECTS

Recent research in remaining burst strength prediction models for corroded pipeline has found that the material strain hardening property (stress-strain curve shape) is crucial for improving the prediction accuracy. The comparison between finite element analysis (FEA) and full-scale burst test results in a recent study also demonstrated strong evidence of the plastic instability failure mechanism for pipe samples with corrosion defects, suggesting that the strain hardening property has a key role in the burst strength of corroded pipes. In this paper, analytical burst pressure prediction models for pipes with and without corrosion defects are briefly reviewed to illustrate the theoretical basis for including the strain hardening property in the model prediction. A suite of parametric FEA was then conducted on previously tested pipe samples with two different materials to further investigate the effect of the strain hardening property on the burst pressure prediction of corroded pipelines. Based on the test evidence from a recent study, a plastic instability-based failure criterion was proposed for FEA prediction of the burst pressure. The proposed failure criterion was further validated by full-scale burst test results referenced in this study. Based on the FEA burst pressure prediction with the new failure criterion, the effect of the strain hardening property on burst strength of pipe samples with corrosion defects was quantitatively evaluated. Using the parametric FEA results, selected remaining burst strength models were critically examined. The outcome of the model assessment provided a basis for future improvement of these models.