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51318-11627-A Semi-Quantitative Analysis of Dents Associated with Corrosion: a reliability-based approach

Quantitative analysis of (pipeline) dents (QuAD) was presented at NACE Corrosion 2017. A new semi‐quantitative analysis of dents (SQuAD) capable of analyzing a large number of dents associated with corrosion features with a reasonable computational effort is proposed herein.

Product Number: 51318-11627-SG
Author: Sherif Hassanien / Doug Langer
Publication Date: 2018
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$20.00
$20.00

A novel quantitative approach of assessing dented liquid pipelines associated with corrosion using finite element and reliability analysis was presented at NACE Corrosion 2017; namely, quantitative analysis of dents (QuAD). Regardless the novelty of the approach and the rigor that brings, it is not considered feasible to implement consistently across a large pipeline system. A new semi‐quantitative analysis of dents (SQuAD) capable of analyzing a large number of dents associated with corrosion features with a reasonable computational effort is proposed herein. SQuAD is developed using a strain‐based limit state, where the strain demand is determined using ASME B31.8 standard and the capacity is determined by a combination of API 5L and CSA Z662 Annex O limits. The ASME model is expanded to allow complex dents to be analyzed through the use of qualitative multipliers (determined based on subject matter expert feedback), which help to account for operating conditions, dent location, dent shape, and the presence of corrosion. The reliability analysis is performed using Monte Carlo simulations or analytical reliability techniques based on a combination of the ILI measurement data and the tool accuracy specifications. A series of validation tests were performed to compare the results against

QuAD results. The model was found to provide conservative predictions of the FEA results. The intent of the use of this model is to work as a tool to elicit critical dents with corrosion features for further QuAD analysis. The paper presents the details of model development and validation examples. Moreover, it discusses the limitations of the proposed approach along with potential continuous improvements.

Key words: Pipeline dents, corrosion, quantitative and semi‐quantitative integrity reliability analysis, strain limit state.

A novel quantitative approach of assessing dented liquid pipelines associated with corrosion using finite element and reliability analysis was presented at NACE Corrosion 2017; namely, quantitative analysis of dents (QuAD). Regardless the novelty of the approach and the rigor that brings, it is not considered feasible to implement consistently across a large pipeline system. A new semi‐quantitative analysis of dents (SQuAD) capable of analyzing a large number of dents associated with corrosion features with a reasonable computational effort is proposed herein. SQuAD is developed using a strain‐based limit state, where the strain demand is determined using ASME B31.8 standard and the capacity is determined by a combination of API 5L and CSA Z662 Annex O limits. The ASME model is expanded to allow complex dents to be analyzed through the use of qualitative multipliers (determined based on subject matter expert feedback), which help to account for operating conditions, dent location, dent shape, and the presence of corrosion. The reliability analysis is performed using Monte Carlo simulations or analytical reliability techniques based on a combination of the ILI measurement data and the tool accuracy specifications. A series of validation tests were performed to compare the results against

QuAD results. The model was found to provide conservative predictions of the FEA results. The intent of the use of this model is to work as a tool to elicit critical dents with corrosion features for further QuAD analysis. The paper presents the details of model development and validation examples. Moreover, it discusses the limitations of the proposed approach along with potential continuous improvements.

Key words: Pipeline dents, corrosion, quantitative and semi‐quantitative integrity reliability analysis, strain limit state.

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51318-11630-Internal Corrosion Direct Assessment of a Wet Gas Pipeline

Product Number: 51318-11630-SG
Author: Xihua S. He / Debashis Basu / and Osvaldo Pensado / Jianyun Mei / Bibo Zhang / Hongbo Wu / Yongzhao Fan / Deqiang Cai / Yang Li
Publication Date: 2018
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