Revised Corrosion Management With Reliability Based Excavation Criteria

2008 ◽  
Author(s):  
Shahani Kariyawasam ◽  
Warren Peterson
Keyword(s):  
Case Studies ◽  
Pressure Ratio ◽  
Reliability Assessment ◽  
Assessment Method ◽  
Integrity Assessment ◽  
Reliability Based Design ◽  
Defect Growth ◽  
Rupture Pressure ◽  
Integrity Assessments ◽  
Growth Assessment

For decades, TransCanada Pipelines has used inline inspection (ILI) to manage the threat of corrosion on gas pipelines. Immediate integrity was addressed using rupture pressure ratio and leak criteria, and future integrity was addressed using a growth assessment. However, a review of excavations based on predictions of defect growth shows that few excavations actually lead to repairs. This study investigated the areas of undue conservatism in both the integrity assessments and the excavation criteria. All aspects of the immediate and future integrity assessment based on ILI were examined. All relevant uncertainties were accounted for in calculating the reliability of the pipeline. A new basis of defining excavation criterion was established based on a reliability assessment and calibration. This criterion was validated against previous ILI based excavations which reveal the features that actually required repair. The criterion was also compared to reliability based criteria recommended in Annex O of the CSA Z662 which gives guidelines for Reliability Based Design and Assessment. This paper addresses the practical limitation of data and presents methods for extracting best information from available data. Case studies that demonstrate the application of the revised assessment method and criterion are also discussed.

An Efficient Approach for Reliability-Based Design Optimization Combined Sequential Optimization with Approximate Models

2018 ◽  
Vol 15 (04) ◽  
pp. 1850018 ◽  
Author(s):  
Bao Quoc Doan ◽  
Guiping Liu ◽  
Can Xu ◽  
Minh Quang Chau
Keyword(s):  
Design Optimization ◽  
Reliability Assessment ◽  
Latin Hypercube Sampling ◽  
Assessment Method ◽  
Probabilistic Constraints ◽  
Sequential Optimization ◽  
Reliability Based Design Optimization ◽  
Efficient Approach ◽  
Reliability Based Design ◽  
Approximate Models

Reliability-based design optimization (RBDO) involves evaluation of probabilistic constraints which can be time-consuming in engineering structural design problems. In this paper, an efficient approach combined sequential optimization with approximate models is suggested for RBDO. The radial basis functions and Latin hypercube sampling are used to construct approximate models of the probabilistic constraints. Then, a sequential optimization with approximate models is carried out by the sequential optimization and reliability assessment method which includes a serial of cycles of deterministic optimization and reliability assessment. Three numerical examples are presented to demonstrate the efficiency of the proposed approach.

Reliability-Based Design Optimization Using Step Length Adjustment Algorithm and Sequential Optimization and Reliability Assessment Method

2019 ◽  
Vol 16 (07) ◽  
pp. 1850109 ◽  
Author(s):  
Ping Yi ◽  
Dongchi Xie ◽  
Zuo Zhu
Keyword(s):  
Design Optimization ◽  
Reliability Assessment ◽  
Step Length ◽  
Assessment Method ◽  
Sequential Optimization ◽  
Target Point ◽  
Reliability Based Design Optimization ◽  
Reliability Based Design ◽  
Inverse Reliability Analysis ◽  
Minimum Performance Target Point

A step length adjustment (SLA) iterative algorithm was proposed for locating the minimum performance target point (MPTP) in the inverse reliability analysis. This paper elaborates SLA and two deliberately designed numerical examples are used to compare SLA with other algorithms appearing in recent literatures for locating MPTP. The results show that SLA is much more robust and efficient. Then SLA and sequential optimization and reliability assessment (SORA) are combined to solve reliability-based design optimization (RBDO) problems. In the reliability assessment of SORA, with the design obtained from the previous cycle, SLA is used to locate MPTP. Then in the deterministic optimization, the boundaries of violated constraints are shifted to the feasible direction according to the MPTP obtained in the reliability assessment. Several examples frequently cited in similar studies are used to compare SORA-SLA with other RBDO algorithms. The results indicate the effectiveness and robustness of SORA-SLA.

Sequential Optimization and Reliability Assessment Method for Efficient Probabilistic Design

2004 ◽  
Vol 126 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Xiaoping Du ◽  
Wei Chen
Keyword(s):  
Robust Design ◽  
Reliability Assessment ◽  
Simulation Models ◽  
Assessment Method ◽  
Side Impact ◽  
Sequential Optimization ◽  
Probabilistic Design ◽  
Deterministic Optimization ◽  
Probabilistic Optimization ◽  
Reliability Based Design

Probabilistic design, such as reliability-based design and robust design, offers tools for making reliable decisions with the consideration of uncertainty associated with design variables/parameters and simulation models. Since a probabilistic optimization often involves a double-loop procedure for the overall optimization and iterative probabilistic assessment, the computational demand is extremely high. In this paper, the sequential optimization and reliability assessment (SORA) is developed to improve the efficiency of probabilistic optimization. The SORA method employs a single-loop strategy with a serial of cycles of deterministic optimization and reliability assessment. In each cycle, optimization and reliability assessment are decoupled from each other; the reliability assessment is only conducted after the deterministic optimization to verify constraint feasibility under uncertainty. The key to the proposed method is to shift the boundaries of violated constraints (with low reliability) to the feasible direction based on the reliability information obtained in the previous cycle. The design is quickly improved from cycle to cycle and the computational efficiency is improved significantly. Two engineering applications, the reliability-based design for vehicle crashworthiness of side impact and the integrated reliability and robust design of a speed reducer, are presented to demonstrate the effectiveness of the SORA method.

Sequential Optimization and Reliability Assessment Method for Efficient Probabilistic Design

2002 ◽  
Author(s):  
Xiaoping Du ◽  
Wei Chen
Keyword(s):  
Robust Design ◽  
Optimization Design ◽  
Reliability Assessment ◽  
Assessment Method ◽  
Side Impact ◽  
Probabilistic Constraints ◽  
Sequential Optimization ◽  
Probabilistic Design ◽  
Probabilistic Optimization ◽  
Reliability Based Design

Probabilistic optimization design offers tools for making reliable decisions with the consideration of uncertainty associated with design variables/parameters and simulation models. In a probabilistic design, such as reliability-based design and robust design, the design feasibility is formulated probabilistically such that the probability of the constraint satisfaction (reliability) exceeds the desired limit. The reliability assessment for probabilistic constraints often involves an iterative procedure; therefore, two loops are involved in a probabilistic optimization. Due to the double-loop procedure, the computational demand is extremely high. To improve the efficiency of a probabilistic design, a novel method – sequential optimization and reliability assessment (SORA) is developed in this paper. The SORA method employs a single-loop strategy where a serial of cycles of optimization and reliability assessment is employed. In each cycle optimization and reliability assessment are decoupled from each other; no reliability assessment is required within optimization and the reliability assessment is only conducted after the optimization. The key concept of the proposed method is to shift the boundaries of violated deterministic constraints (with low reliability) to the feasible direction based on the reliability information obtained in the previous cycle. Hence the design is quickly improved from cycle to cycle and the computational efficiency is improved significantly. Two engineering applications, the reliability-based design for vehicle crashworthiness of side impact and the integrated reliability and robust design of a speed reducer, are presented to demonstrate the effectiveness of the SORA method.

scholarly journals Photovoltaic BIPV Systems and Architectural Heritage: New Balance between Conservation and Transformation. An Assessment Method for Heritage Values Compatibility and Energy Benefits of Interventions

2021 ◽  
Vol 13 (9) ◽  
pp. 5107
Author(s):  
Cristina S. Polo López ◽  
Floriana Troia ◽  
Francesco Nocera
Keyword(s):  
Case Studies ◽  
Complete Information ◽  
Assessment Method ◽  
Architectural Heritage ◽  
Historical Building ◽  
Improve Energy Efficiency ◽  
Building Integrated Photovoltaic ◽  
Architectural Language ◽  
Guidance Documents ◽  
The Aesthetic

This paper proposes to identify an approach methodology for the incorporation of building-integrated photovoltaic systems (BIPV) in existing architectural heritage, considering regulatory, conservation and energy aspects. The main objective is to provide information about guidance criteria related to the integration of BIPV in historical buildings and about intervention methods. That will be followed by the development of useful data to reorient and update the guidelines and guidance documents, both for the design approach and for the evaluation of potential future interventions. The research methodology includes a categorization and analysis of European and Swiss case studies, taking into account the state of preservation of the building before the intervention, the data of the applied photovoltaic technology and the aesthetic and energy contribution of the intervention. The result, in the form of graphic schedules, provides complete information for a real evaluation of the analyzed case studies and of the BIPV technological system used in historical contexts. This research promotes a conscious BIPV as a real opportunity to use technology and a contemporary architectural language capable of dialoguing with pre-existing buildings to significantly improve energy efficiency and determine a new value system for the historical building and its environment.

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