Dynamic Fault Tree Analysis Based on Dynamic Uncertain Causality Graph

2018 ◽  
Author(s):  
Zhenxu Zhou ◽  
Chunling Dong ◽  
Qin Zhang
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Logic Gates ◽  
Industrial Systems ◽  
Dynamic Fault Tree ◽  
Sequential Logic ◽  
Dynamic Uncertain Causality Graph ◽  
Disjoint Product ◽  
Logical Mapping ◽  
Analytical Approaches

Dynamic Fault Tree (DFT) has drawn attention from comprehensive industrial systems in recent years. Many analytical approaches are developed to analyze DFT, such as Markov Chain based method, Inclusion-Exclusion Rule based method, and Sum-of-Disjoint-Product theory based method. Novel methods such as Bayesian Network and Petri Net are also used to solve DFT. However, Basic events are usually assumed unrepairable and are restricted to specific probabilistic distributions. And some methods may suffer from combination explosion. This paper applies Dynamic Uncertain Causality Graph (DUCG) to analyze DFT to overcome the aforementioned issues. DUCG is a newly proposed Probabilistic Graphic Model for large complex industrial systems which allows for dynamics, uncertainties and logic cycles. The DUCG based methodology can be summarized as event mapping, logical mapping, and numerical mapping. This paper studies how to map the PAND, FDEP, SEQ AND SPARE sequential logic gates into equivalent representations in DUCG. With the DUCG representation mode, one can analyze DFT with algorithms in DUCG. Future work will be done on benchmark tests and on software development.

Analysis on Dynamic Fault Tree Based on Fuzzy Set

2011 ◽  
Vol 110-116 ◽  
pp. 2416-2420 ◽  
Author(s):  
Li Ping Yang
Keyword(s):  
Fuzzy Set ◽  
Fault Tree ◽  
Dynamic Logic ◽  
Fault Tree Analysis ◽  
Logic Gates ◽  
Minimum Cut ◽  
Tree Analysis ◽  
Dynamic Fault Tree ◽  
Large Complex System ◽  
Cut Set

In case of fault tree analysis of large complex system, the probability of bottom event in dynamic fault tree is uncertain in some cases. To address the problem, the paper presented a dynamic fault tree analysis method based on fuzzy set computation. The method separates logic attributes and timing attributes of dynamic logic gates. It can convert dynamic fault tree into static fault tree not considering timing constraints and obtain minimum cut set of static fuzzy fault tree with set operations, then the concept of minimum cut set is extended to dynamical minimum cut sequence. Thus, the dynamic fault tree was analyzed in both qualitative and quantitative aspects, which solve the problem that it is difficult to assign value of event probability in previously process.

Fault Tree Analysis Based on Dynamic Uncertain Causality Graph

2017 ◽  
Author(s):  
Zhenxu Zhou ◽  
Qin Zhang
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Tree Analysis ◽  
Industrial Systems ◽  
Weapon Systems ◽  
Chemical Systems ◽  
Binary State ◽  
Dynamic Uncertain Causality Graph

Fault Tree Analysis (FTA) has been widely applied to large, complex industrial systems like nuclear power plants, chemical systems, and weapon systems. Events in classical FTA are assumed binary-state and s-independent but multi-state, dependencies and logic cycles may exist within FTs. Moreover, causalities in FTA are assumed deterministic, while sometimes they may be uncertain. This paper applies Dynamic Uncertain Causality Graph (DUCG) in FTA to overcome aforementioned issues. This paper shows that any FT can be mapped into a DUCG graph. And with DUCG representation model and algorithm, additional modeling and analytical power are obtained. Multi-value, dependencies, logic cycles, and non-deterministic causalities in FTA are solved. This paper also depicts how to calculate the importance measurement, predict failure, and diagnose fault. The results reveal the effectiveness and feasibility of this methodology.

Safety Analysis Model of DUCG Based on FMEA/FTA

2018 ◽  
Author(s):  
Zhenxu Zhou ◽  
Hao Nie ◽  
Chunling Dong ◽  
Qin Zhang
Keyword(s):  
Failure Modes ◽  
Fault Tree Analysis ◽  
Safety Analysis ◽  
Nuclear Industry ◽  
Analysis Model ◽  
Industrial Systems ◽  
The Past ◽  
Research Cycle ◽  
Dynamic Uncertain Causality Graph ◽  
Analytical Power

Failure Modes and Effects Analysis (FMEA) is a useful tool to find possible flaws, to reduce cost and to shorten research cycle in complex industrial systems. Fault Tree Analysis (FTA) has gained credibility over the past years, not only in nuclear industry, but also in other industries like aerospace, petrochemical, and weapon. Both FMEA and FTA are effective techniques in safety analysis, but there are still many uncertain factors in them that are not well addressed until now. This paper combines FMEA and FTA based on Dynamic Uncertain Causality Graph (DUCG) to solve this issue. Firstly, the FMEA model is mapped into a corresponding DUCG graph. Secondly, FTA model is mapped into a corresponding DUCG graph. Thirdly, combine the above DUCG graphs. Finally, users can modify the combined DUCG graph and calculations are made. This paper bridges the gap between FMEA and FTA by combining the two methods using DUCG. And additional modeling power and analytical power can be achieved with the advantages of the combined DUCG safety analysis model and its inference algorithm. This method can also promote the application of DUCG in the system reliability and safety analysis. An example is used to illustrate this method.

Dynamic Fault Tree Analysis

2020 ◽  
pp. 73-112
Author(s):  
Koorosh Aslansefat ◽  
Sohag Kabir ◽  
Youcef Gheraibia ◽  
Yiannis Papadopoulos
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Tree Analysis ◽  
Dynamic Fault Tree

Developing an Efficient Approach for Unmanned Aerial Vehicle Reliability Analysis

2020 ◽  
Author(s):  
Ahmad Khayyati ◽  
Mohammad Pourgol-Mohammad
Keyword(s):  
Reliability Analysis ◽  
Block Diagram ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Dynamic Fault Tree ◽  
Safety And Reliability ◽  
Time Dependencies ◽  
Aerial Vehicle ◽  
Redundant Component ◽  
High Level

Abstract Unmanned Aerial Vehicles (UAV) are increasingly get popularity in many applications. Their operation requires high level of safety and reliability to accomplish successful missions. In this study, the reliability was comparatively analyzed by different available approaches to select the efficient method. First, failure model of the system is developed. Then, three different scenarios are considered to study the effect of redundancies on the system reliability results. In the first scenario, there is no redundancy where in the second scenario there is only one redundant component and in the third scenario, there are three redundant components. Static reliability analysis such as Fault Tree Analysis (FTA), Reliability Block Diagram (RBD), Markov Chain (MC), and Bayesian Networks (BN) are applied on proposed scenarios and results are obtained. Regarding to time dependencies between redundant components, a dynamic-based methodology is also developed in this study through applying Dynamic Fault Tree (DFT) analysis. Proposed static and dynamic approaches are applied on an UAV as a case study and results are discussed. Finally, characteristics of each methodology and related conditions are clarified for selecting the efficient reliability analysis approach.

scholarly journals Modelling and Resolution of Dynamic Reliability Problems by the Coupling of Simulink and the Stochastic Hybrid Fault Tree Object Oriented (SHyFTOO) Library

Information ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 283 ◽  
Author(s):  
Chiacchio ◽  
Aizpurua ◽  
Compagno ◽  
Khodayee ◽  
D’Urso
Keyword(s):  
Deterministic Model ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Object Oriented ◽  
Software Library ◽  
Tree Model ◽  
Dynamic Reliability ◽  
Simulink Model ◽  
Dynamic Fault Tree ◽  
Dependability Analysis

Dependability assessment is one of the most important activities for the analysis of complex systems. Classical analysis techniques of safety, risk, and dependability, like Fault Tree Analysis or Reliability Block Diagrams, are easy to implement, but they estimate inaccurate dependability results due to their simplified hypotheses that assume the components’ malfunctions to be independent from each other and from the system working conditions. Recent contributions within the umbrella of Dynamic Probabilistic Risk Assessment have shown the potential to improve the accuracy of classical dependability analysis methods. Among them, Stochastic Hybrid Fault Tree Automaton (SHyFTA) is a promising methodology because it can combine a Dynamic Fault Tree model with the physics-based deterministic model of a system process, and it can generate dependability metrics along with performance indicators of the physical variables. This paper presents the Stochastic Hybrid Fault Tree Object Oriented (SHyFTOO), a Matlab® software library for the modelling and the resolution of a SHyFTA model. One of the novel features discussed in this contribution is the ease of coupling with a Matlab® Simulink model that facilitates the design of complex system dynamics. To demonstrate the utilization of this software library and the augmented capability of generating further dependability indicators, three different case studies are discussed and solved with a thorough description for the implementation of the corresponding SHyFTA models.

scholarly journals Maintenance modelling for computer-based systems

2001 ◽  
Vol 215 (3) ◽  
pp. 221-231 ◽  
Author(s):  
L Meshkat ◽  
J B Dugan ◽  
J Andrews
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
System Failure ◽  
Time Schedule ◽  
Functional Capabilities ◽  
Dynamic Fault Tree ◽  
Analysis Methodology ◽  
Expected Performance ◽  
Dependability Analysis ◽  
Computer Based

A framework is presented for incorporating maintenance into a dependability analysis methodology for computer-based systems. Two types of maintenance are considered: failure-driven maintenance and time-driven maintenance. Failure-driven maintenance or repair is carried out when the system (or component) performance deviates from its expected performance and consists of all tasks performed to restore the functional capabilities of failed items, principally diagnosis and repair. Time-driven or scheduled maintenance is conducted on a specific time schedule in order to prevent system failure. There may be dependencies between different components of a system with regard to their maintenance plans. These dependencies arise either because a component has maintenance priority over one or more components or because the maintenance of a certain component implies the maintenance of other components. Constructs are presented for modelling these dependencies in the context of dynamic fault tree analysis and a methodology is developed for solving the fault tree. The dynamic fault tree constructs effectively capture the failure dependencies between components. The approach is illustrated with an example based on a water deluge system.

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