Control Parameters and Quantification for System Reliability Design

2009 ◽  
Vol 628-629 ◽  
pp. 215-220
Author(s):  
Li Yang Xie ◽  
Wen Qiang Lin
Keyword(s):  
System Reliability ◽  
Uncertainty Component ◽  
System Complexity ◽  
Component Reliability ◽  
Reliability Design ◽  
Component Strength ◽  
Configuration System ◽  
Failure Dependence ◽  
Component Failures ◽  
The Relationship

The reliability of a mechanical system is not simply determined by the reliabilities of components composing the system. For a specified system configuration, system reliability depends on not only component reliability, but also the degree of the dependence among component failures, which can be characterized by load roughness in an extent. In the same way, system complexity depends on not only the number of components that the system contains but also the dependence among component failures. This paper analyzes the main factors that affect the relationship between system reliability and component reliabilities in term of component failure dependence. The factors include load uncertainty, component strength uncertainty, and load roughness as well. Traditional parameter describing system complexity is modified, new parameter to describe component complexity is defined. These parameters play important rule for system reliability design or system reliability allocation.

scholarly journals Development of Failure Cause–Impact–Duration (CID) Plots for Water Supply and Distribution System Management

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1719 ◽  
Author(s):  
Seungyub Lee ◽  
Sueyeun Oak ◽  
Donghwi Jung ◽  
Hwandon Jun
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
System Management ◽  
Failure Frequency ◽  
Supply And Distribution ◽  
Failure Classification ◽  
Component Failures ◽  
The Impact ◽  
The Relationship ◽  
Impact Duration

Understanding the impact and duration (consequences) of different component failures (cause) in a water supply and distribution system (WSDS) is a critical task for water utilities to develop effective preparation and response plans. During the last three decades, few efforts have been devoted to developing a visualization tool to display the relationship between the failure cause and its consequences. This study proposes two visualization methods to effectively show the relationship between the two failure entities: A failure cause–impact–duration (CID) plot, and a bubble plot. The former is drawn for an effective snapshot on the range (extent) of failure duration and the impact of different failures, whereas the latter provides failure frequency information. A simple and practical failure classification system is also introduced for producing the two proposed plots effectively. To verify the visualization schemes, we collected records of 331 WSDS component failures that occurred in South Korea between 1980 and 2018. Results showed that (1) the proposed CID plot can serve as a useful tool for identifying most minor and major WSDS failures, and (2) the proposed bubble plot is useful for determining significant component failures with respect to their failure consequences and occurrence likelihoods.

A Partial Safety Factor Method for System Reliability Prediction With Outsourced Components

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Zhengwei Hu ◽  
Xiaoping Du
Keyword(s):  
System Reliability ◽  
Joint Probability ◽  
System Level ◽  
Safety Factors ◽  
Component Reliability ◽  
Reliability Method ◽  
Component Supplier ◽  
Partial Safety Factors ◽  
Joint Probability Density ◽  
Probability Density Function Pdf

System reliability is usually predicted with the assumption that all component states are independent. This assumption may not accurate for systems with outsourced components since their states are strongly dependent and component details may be unknown. The purpose of this study is to develop an accurate system reliability method that can produce complete joint probability density function (PDF) of all the component states, thereby leading to accurate system reliability predictions. The proposed method works for systems whose failures are caused by excessive loading. In addition to the component reliability, system designers also ask for partial safety factors for shared loadings from component suppliers. The information is then sufficient for building a system-level joint PDF. Algorithms are designed for a component supplier to generate partial safety factors. The method enables accurate system reliability predictions without requiring proprietary information from component suppliers.

scholarly journals Reliability Modeling and Assessment of Component with Multiple Weak Sites under Complex Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Wenxue Qian ◽  
Xiaowei Yin ◽  
Liyang Xie
Keyword(s):  
Static Loading ◽  
Safety Margin ◽  
Complex Loading ◽  
The Other ◽  
Reliability Model ◽  
Reliability Modeling ◽  
Component Reliability ◽  
Reliability Design ◽  
Practical Engineering ◽  
Weak Site

A component with multiple weak sites is widely used in practical engineering and the existence of multiple weak sites can significantly decrease the component reliability. On the other hand, only a few components bear static loading and most components bear dynamic loading. In this paper, a reliability model of isomorphic component with multiple weak sites is built based on an order statistics model and the influences of strength decentrality and loading decentrality on isomorphic component with multiple weak sites are discussed. Furthermore the influence of loading times is studied in detail. The results show that unlike a component with only one weak site, not only does the failure of a component with multiple weak sites have a relationship with the safety margin, but there also exist relationships with the number of weak sites, the loading roughness, and loading times. The work in this paper is of some guiding significance in reliability design and assessment of a component with multiple weak sites under complex loading.

Reliability Model for Complex Mechanical Component Design

2013 ◽  
Vol 365-366 ◽  
pp. 28-31
Author(s):  
Li Yang Xie ◽  
Wen Xue Qian ◽  
Ning Xiang Wu
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
Statistical Dependence ◽  
Series System ◽  
Reliability Model ◽  
Component Reliability ◽  
Damage Site ◽  
Mechanical Component ◽  
Component Design ◽  
Element Failure

Taking into account the uncertainty in material property and component quality, a complex mechanical component such as a gear should be treated as a series system instead of a component when evaluating its reliability, since there exist many sites of equal likelihood to fail. Besides, conventional system reliability model is not applicable to such a system because of the statistical dependence among the failures of the every element (damage site). The present paper presents a model to estimate complex mechanical component reliability by incorporating order statistic of element strength into load-strength interference analysis, which can deal with multiple failure mechanisms, reflect statistical dependence among element failure events and that among different failure modes.

Modification for Fatigue Curves Based on Component Reliability

2012 ◽  
Vol 590 ◽  
pp. 116-121
Author(s):  
Li Juan Cao ◽  
Shou Ju Li ◽  
Yi Jin Shangguan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Safety Evaluation ◽  
Evaluation Procedure ◽  
Element Analysis ◽  
Component Reliability ◽  
The Relationship

Based on component reliability and scatter factors of material, a new procedure is proposed to modify fatigue curves. The scatter characteristics of fatigue life and strength are investigated. The relationship between modified S-N curves and scatter factors of material is presented. The safety evaluation procedure for fatigue damage based on finite element analysis is performed.

Fatigue and Fracture Reliability and Maintainability of TLP Tendons

1993 ◽  
Vol 115 (2) ◽  
pp. 137-141 ◽  
Author(s):  
C. J. Kung ◽  
P. H. Wirsching
Keyword(s):  
System Reliability ◽  
Structural Integrity ◽  
Probability Of Detection ◽  
Structural Performance ◽  
Periodic Inspection ◽  
Maintenance Program ◽  
Fatigue And Fracture ◽  
Relationship Of ◽  
Design Factors ◽  
The Relationship

A tension leg platform (TLP) tendon system experiences oscillatory tensile stresses, and therefore is vulnerable to fatigue and fracture. Because design factors have significant uncertainty, a reliability analysis to quantify structural performance is appropriate. A maintenance program of periodic inspection and repair shows promise for improving system reliability and enhancing structural integrity. The performance of a TLP tendon system was simulated in order to study the relationship of design factors to system reliability. Effects on system reliability and maintenance performance (repair and replacement rates) can be studied as a function of (a) number of joints, J; (b) number of members, M; (c) inspection frequency; (d) inspection sensitivity as defined by the POD (probability of detection) curve; (e) ultimate strength; (f) repair policy; etc. The performance of an initially damaged or flawed tendon system is investigated. The reliability of a system that uses pressurized tendons to detect through-thickness cracks is studied, as is the vulnerability of the tendon system before replacement of broken tendons.

Network System Reliability and Unit Probability Importance Based on Monte Carlo Method

2014 ◽  
Vol 1049-1050 ◽  
pp. 1458-1462
Author(s):  
Rao Bin
Keyword(s):  
Reliability Analysis ◽  
System Reliability ◽  
Network Reliability ◽  
Approximate Algorithm ◽  
Network System ◽  
Reliability Design ◽  
Precise Calculation ◽  
Improve Calculation ◽  
Factor Decomposition ◽  
State Enumeration

The network system reliability research contains a number of problems, such as: Reliability analysis and reliability design, reliability, maintenance and a lot of problems so on. The calculation of reliability of the network is the important area of network reliability analysis, State enumeration method and principle of a class, don't pay the product and method, the factor decomposition method is a classic accurate algorithm of computing network reliability. Due to the difficulty of precise calculation, in the method, appeared and bound method, Monte carol method, the reliability of the approximate algorithm. Compared with the accurate algorithm, approximate algorithm is still under development. So far, no recognized classic algorithms, so the method to improve calculation accuracy, reduce the complexity of the target of the researchers.

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