First-order reliability method-based system reliability analyses of corroding pipelines considering multiple defects and failure modes

2017 ◽  
Vol 13 (11) ◽  
pp. 1451-1461 ◽  
Author(s):  
Changqing Gong ◽  
Wenxing Zhou
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
First Order Reliability Method ◽  
First Order ◽  
Multiple Defects ◽  
Reliability Method

An Efficient Methodology for the Reliability Analysis of Corroding Pipelines

2012 ◽  
Author(s):  
S. Zhang ◽  
W. Zhou
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
Weighting Factor ◽  
Probability Weighting ◽  
Index Method ◽  
First Order ◽  
Corrosion Defect ◽  
Small Leak ◽  
Reliability Method ◽  
Dependent Failure

This paper describes an efficient methodology that utilizes the first order reliability method (FORM) and system reliability approaches to evaluate the time-dependent failure probabilities of a pressurized pipeline at a single active corrosion defect considering three different failure modes, i.e. small leak, large leak and rupture. The criteria for distinguishing small leak, large leak and rupture at a given corrosion defect are established based on the information in the literature. The wedge integral and probability weighting factor methods are used to evaluate the probabilities of small leak and burst, whereas the conditional reliability index method is used to evaluate the probabilities of large leak and rupture. Two numerical examples are used to illustrate the accuracy, efficiency and robustness of the proposed methodology. The proposed methodology can be used to facilitate reliability-based corrosion management programs for energy pipelines.

An Efficient Methodology for the Reliability Analysis of Corroding Pipelines

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Shenwei Zhang ◽  
Wenxing Zhou
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
Weighting Factor ◽  
Probability Weighting ◽  
Index Method ◽  
First Order ◽  
Corrosion Defect ◽  
Small Leak ◽  
Reliability Method ◽  
Dependent Failure

This paper describes an efficient methodology that utilizes the first order reliability method (FORM) and system reliability approaches to evaluate the time-dependent failure probabilities of a pressurized pipeline at a single active corrosion defect considering three different failure modes, i.e., small leak, large leak, and rupture. The criteria for distinguishing small leak, large leak, and rupture at a given corrosion defect are established based on the information in the literature. The wedge integral and probability weighting factor methods are used to evaluate the probabilities of small leak and burst, whereas the conditional reliability index method is used to evaluate the probabilities of large leak and rupture. Two numerical examples are used to illustrate the accuracy, efficiency and robustness of the proposed methodology. The proposed methodology can be used to facilitate reliability-based corrosion management programs for energy pipelines.

An accuracy analysis method for first-order reliability method

2018 ◽  
Vol 233 (12) ◽  
pp. 4319-4327 ◽  
Author(s):  
Zhenzhong Chen ◽  
Zihao Wu ◽  
Xiaoke Li ◽  
Ge Chen ◽  
Guangfeng Chen ◽  
...  
Keyword(s):  
Structural Reliability ◽  
Nonlinear Problems ◽  
Accuracy Analysis ◽  
Analysis Method ◽  
First Order Reliability Method ◽  
First Order ◽  
Reliability Level ◽  
Reliability Method ◽  
Value Range ◽  
Crashworthiness Design

The first-order reliability method is widely used for structural reliability analysis; however, its accuracy would become worse for nonlinear problems. This paper proposes the accuracy analysis method of the first-order reliability method, which considers the worst cases when using the first-order reliability method and gives the possible value range of the probability of safety. The accuracy analysis method can evaluate the reliability level of the first-order reliability method when the failure surfaces are nonlinear. The calculation formula for the possible value range of the probability of safety is proposed, and its trend as the dimensions and reliability rise is also discussed in this paper. A numerical example and a honeycomb crashworthiness design are presented to validate the accuracy of the first-order reliability method, and the results show that they are located within the possible value range proposed in this paper.

Sensitivity of Vessel Responses to Environmental Contours of Extreme Sea States

2015 ◽  
Author(s):  
Curtis Armstrong ◽  
Christopher Chin ◽  
Irene Penesis ◽  
Yuriy Drobyshevski
Keyword(s):  
Case Studies ◽  
Return Period ◽  
Significant Wave Height ◽  
Peak Period ◽  
First Order Reliability Method ◽  
First Order ◽  
Long Wave ◽  
Contour Lines ◽  
Reliability Method ◽  
Extreme Responses

A comparative study of two methods for the generation of the environmental contours is presented investigating the sensitivity of the predicted extreme vessel responses to the type of the contour lines. Two approaches for the generation of environmental contours of the significant wave height and peak period are compared: the Inverse First Order Reliability Method (IFORM) and Constant Probability Density (CPD) approach. Case studies include several global responses of a ship-shaped weather-vaning vessel and a semisubmersible platform. The case studies reveal that the differences between the IFORM and CPD contours are more pronounced in the range of long wave periods. Vessel responses which are less sensitive to long wave periods exhibit less difference (less than 1.0%) in their maximum values between the two types of contours. In contrast, responses which are sensitive to long wave periods show significantly larger differences of up to 7.0%. Uncertainties also exist in the predicted extreme responses where the environmental contour and the response isoline behave tangentially. Differences between the extreme responses produced by the two contours generally decrease with an increase in return period; however exceptions exist due to the tangential behaviour. It is advised that these sensitivities should be taken into consideration when the environmental contours are used in the design.

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