Reliability Prediction of Long-Distance Transmission Pipelines With a Three-Layer Polyethylene Coating Employing Delay-Time Concepts

2017 ◽  
Author(s):  
Xiufeng Li ◽  
Haijun Hu ◽  
Guangxu Cheng ◽  
Yun Li ◽  
Chengxian Yin
Keyword(s):  
Failure Probability ◽  
Delay Time ◽  
Failure Process ◽  
Long Distance ◽  
Periodic Inspection ◽  
Polyethylene Coating ◽  
Time Concepts ◽  
Pipe Segment ◽  
Distribution Parameters ◽  
Transmission Pipelines

Long-distance transmission pipelines with 3PE coating undergo a two-stage failure process, including the damage process of three-layer polyethylene coating and the failure process of metal pipelines. The two stages are random and independent of each other. A reliability model of transmission pipelines under periodic inspection is presented with the assumptions of delay-time concepts. Functions of maximum likelihood estimations and the goodness of model fit are given. The effect of the inspection interval on reliability is investigated. A case study of Xinqin natural gas transmission pipelines is presented. Data of the pitting depth are obtained at 43 excavation locations. Best estimations of distribution parameters are obtained in a genetic algorithm search. Results show that the average time of coating damage is around 1.04 years. The failure probability of a pipe segment after 36 years’ operation is 1.1E−3 if no inspections are carried out. The failure probability is around 5.5 times the failure probability of a pipe segment with a 6-year periodic inspection. The sensitivity of variance of distribution parameters to failure probability is presented.

scholarly journals Neglect Of Parameter Estimation Uncertainty Can Significantly Overestimate Structural Reliability

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Árpád Rózsás ◽  
Miroslav Sýkora
Keyword(s):  
Parameter Estimation ◽  
Bayesian Statistics ◽  
Failure Probability ◽  
Structural Reliability ◽  
Probabilistic Models ◽  
Estimation Uncertainty ◽  
Point Estimates ◽  
Distribution Parameters ◽  
Order Of Magnitude ◽  
Parameter Estimation Uncertainty

Abstract Parameter estimation uncertainty is often neglected in reliability studies, i.e. point estimates of distribution parameters are used for representative fractiles, and in probabilistic models. A numerical example examines the effect of this uncertainty on structural reliability using Bayesian statistics. The study reveals that the neglect of parameter estimation uncertainty might lead to an order of magnitude underestimation of failure probability.

scholarly journals Parametric Sensitivity Analysis for Importance Measure on Failure Probability and Its Efficient Kriging Solution

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Yishang Zhang ◽  
Yongshou Liu ◽  
Xufeng Yang
Keyword(s):  
Sensitivity Analysis ◽  
Failure Probability ◽  
Computational Effort ◽  
Importance Measure ◽  
Sensitivity Index ◽  
Reliability Engineering ◽  
Parametric Sensitivity ◽  
Distribution Parameters ◽  
The Moment ◽  
Sensitivity Indicator

The moment-independent importance measure (IM) on the failure probability is important in system reliability engineering, and it is always influenced by the distribution parameters of inputs. For the purpose of identifying the influential distribution parameters, the parametric sensitivity of IM on the failure probability based on local and global sensitivity analysis technology is proposed. Then the definitions of the parametric sensitivities of IM on the failure probability are given, and their computational formulae are derived. The parametric sensitivity finds out how the IM can be changed by varying the distribution parameters, which provides an important reference to improve or modify the reliability properties. When the sensitivity indicator is larger, the basic distribution parameter becomes more important to the IM. Meanwhile, for the issue that the computational effort of the IM and its parametric sensitivity is usually too expensive, an active learning Kriging (ALK) solution is established in this study. Two numerical examples and two engineering examples are examined to demonstrate the significance of the proposed parametric sensitivity index, as well as the efficiency and precision of the calculation method.

scholarly journals Global Sensitivity Analysis of Fuzzy Distribution Parameter on Failure Probability and Its Single-Loop Estimation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Lei Cheng ◽  
Zhenzhou Lu ◽  
Luyi Li
Keyword(s):  
Sensitivity Analysis ◽  
Failure Probability ◽  
Global Sensitivity Analysis ◽  
Computational Cost ◽  
Single Loop ◽  
Global Sensitivity ◽  
Sensitivity Indices ◽  
Distribution Parameters ◽  
Input Variables ◽  
Sampling Probability

An extending Borgonovo’s global sensitivity analysis is proposed to measure the influence of fuzzy distribution parameters on fuzzy failure probability by averaging the shift between the membership functions (MFs) of unconditional and conditional failure probability. The presented global sensitivity indices can reasonably reflect the influence of fuzzy-valued distribution parameters on the character of the failure probability, whereas solving the MFs of unconditional and conditional failure probability is time-consuming due to the involved multiple-loop sampling and optimization operators. To overcome the large computational cost, a single-loop simulation (SLS) is introduced to estimate the global sensitivity indices. By establishing a sampling probability density, only a set of samples of input variables are essential to evaluate the MFs of unconditional and conditional failure probability in the presented SLS method. Significance of the global sensitivity indices can be verified and demonstrated through several numerical and engineering examples.

A Self-Organizing Grouping Approach for Ship Traffic Scheduling in Restricted One-Way Waterway

2019 ◽  
Vol 53 (1) ◽  
pp. 83-96
Author(s):  
Xuri Xin ◽  
Kezhong Liu ◽  
Jinfen Zhang ◽  
Shuzhe Chen ◽  
Hongbo Wang ◽  
...  
Keyword(s):  
Delay Time ◽  
Model Simulation ◽  
Time Interval ◽  
Improvement Strategy ◽  
Long Distance ◽  
Ship Traffic ◽  
Proposed Model ◽  
Ship Scheduling ◽  
The Impact ◽  
Self Organizing

AbstractShip scheduling optimization is one of the most effective ways to eliminate the bottlenecks of waterway transportation, especially in restricted one-way waterways. In this study, a novel scheduling model called self-organizing grouping is proposed to minimize two types of delay time, which are the waiting time and the extra navigation time caused by speed reduction. The proposed model schedules ships in an iterative way based on the distributed scheduling mode. To alleviate the impact of local scheduling on the overall traffic efficiency, a grouping method is proposed, in which the ships are divided into different groups based on their arrival time interval. Moreover, the ships in the same group are scheduled to minimize the interferences among them by incorporating a grouping improvement strategy. The strategy is used to deal with the influence of ships with very small speed. Experiments are carried out by comparing the proposed model with the first-come-first-serve model and the ship self-organizing cooperation model. Simulation results show that the delay time is reduced by 25%‐30% and approximately by 5% compared with that from the two models, respectively. Such advantage also exists for different combinations of ship traffic parameters. In addition, long-distance sailing with limited speed can be avoided using the proposed method, which is beneficial to relieve waterway traffic congestion.

Assessment of hydrate blockage risk in long-distance natural gas transmission pipelines

2018 ◽  
Vol 60 ◽  
pp. 256-270 ◽  
Author(s):  
Wenyuan Liu ◽  
Jinqiu Hu ◽  
Xiangfang Li ◽  
Zheng Sun ◽  
Fengrui Sun ◽  
...  
Keyword(s):  
Natural Gas ◽  
Long Distance ◽  
Natural Gas Transmission ◽  
Transmission Pipelines

Reliability-Based Scheme Design for Fault-Crossing of X90 Pipeline

2014 ◽  
Vol 1030-1032 ◽  
pp. 2601-2607
Author(s):  
Yu Qing Liu ◽  
Zhen Yong Zhang ◽  
Kai Wen
Keyword(s):  
Failure Probability ◽  
Oil And Gas ◽  
Theoretical Foundation ◽  
Design Method ◽  
Influence Factors ◽  
Steel Grade ◽  
Pipeline Transportation ◽  
Long Distance ◽  
Reliability Design ◽  
Scheme Design

While high steel grade X70, X80 pipeline has been widely used in long-distance oil and gas pipeline engineering of China, to further improve steel grade to X90 is an effective way to increase the efficiency of pipeline transportation and reduce construction cost. In this paper, the failure probability of earthquake fault crossing of X90 pipeline has been calculated with the strain-based reliability design method and the design scheme has been adjusted according to sensitivity analysis with influence factors of the failure probability of fault-crossing of X90 pipeline, after that the scheme of fault-crossing of X90 pipeline which meets requirements of pipeline reliability has been figured out. This study has laid a theoretical foundation for the application of X90 pipeline in future construction of pipeline engineering.

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