Uncertainty quantification of burst pressure models of corroded pipelines. (December 2020) - Bhardwaj, U.
Abstract: Accurate assessment of the burst pressure of corroded pipes is pivotal for pipelines integrity management and adequate decision-making and thus, meticulous selection of an appropriate prediction model is vital. Several burst strength models have been developed based on analytical, numerical and empirical analyses, often validated by full or small-scale experiments. This paper provides a comprehensive review, calibration and model uncertainty evaluation of a wide range of burst strength models available in the literature relative to a large sample of more than 240 tests of burst pressure covering a variety of steel grades. First, the most appropriate strength model for corrosion free pipes is calibrated by comparing it with extensive test data and the inherent model uncertainty factor is derived. Then, 25 burst strength models for corroded pipelines are categorically analysed in three classes of steel pipe grades, i.e., low (X42 or less to X56), medium (X60 to X70) and high strength (X80 to X120). Statistical parameters such as the mean and absolute mean errors and standard deviation are adopted to analyse and compare the models' performance against test results. The bust strength models of corroded pipelines in the three categories are then calibrated by model uncertainty factors derived from the experimental data. Then, the top 10 models are comparatively analysed in each category to check their performance and uncertainty. Monte Carlo simulation is used to assess the uncertainties with increasing defect depth. The paper concludes exploring the extent of applicability and best utilization of the models for assessing the burst pressure of corroded pipelines. The present study also provides guidance on the calibrated models, which can be used to assess probabilistically the safety of intact and corroded pipelines against burst failure. Highlights: A calibration and model uncertainty evaluation of many burst strength models is made based on more than 240 tests. The most appropriate strength model is calibrated and the inherent model uncertainty factor is derived. Then, 25 burst strength models for corroded pipelines are categorically analysed in three classes of steel pipe grades. The top 10 models are comparatively analysed in each category to check their performance and uncertainty. The conclusion recommends the best utilization of the models for assessing the burst pressure of corroded pipelines.