07_IMechO_SysFtDiag_EEH,LMB&JDA.pdf (186.14 kB)
System fault diagnostics using fault tree analysis
journal contribution
posted on 2008-10-30, 10:29 authored by Emma E. Hurdle, Lisa JacksonLisa Jackson, J.D. AndrewsOver the last 50 years, advances in technology have led to an increase in the
complexity and sophistication of systems. More complex systems can be harder to maintain
and the root cause of a fault more difficult to isolate.
Downtime resultin from a system failure can be dangerous or expensive, depending on the
type of system. In aircraft systems the ability to diagnose quickly the causes of a fault can
have a significant impact on the time taken to rectify the problem and to return the aircraft
to service. In chemical prcess plants the need to diagnose causes of a safety-critical failure in
a system can be vital and a diagnosis may be required within minutes. Speed of fault
isolation can save time, reduce costs, and increase company productivity and therefore
profits. System fault diagnosis is the process of identifying the cause of a malfunction by
observing its effect at various test points.
Fault tree analysis (FTA) is a method that describes all possible causes of a specified system
state in terms of the state of the components within the system. A system model is used to
identify the states that the system should be in at any point in time. This paper presents a
method for diagnosing faults in systems using FTA to explain the deviations from normal
operation observed in sensor outputs. The causes of a system’s failure modes will be
described in terms of the component states. This will be achieved with the use of coherent
and non-coherent fault trees. A coherent fault tree is constructed from AND and OR logic
and therefore considers only component-failed states. The non-coherent method expands
this, allowing the use of NOT logic, which implies that the existence of component-failed
states and component-working states are both taken into account. This paper illustrates the concepts of this method by applying the technique to a simplified water tank level control system.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Aeronautical and Automotive Engineering
Citation
HURDLE, E.E., BARTLETT, L.M. and ANDREWS, J.D., 2008. System fault diagnostics using fault tree analysis. Proceedings of the Institution of Mechanical Engineers, Part O : Journal of Risk and Reliability, 221 (1), pp. 43-55 [DOI: 10.1243/1748006XJRR6]Publisher
© IMechE / Professional Engineering PublishingPublication date
2008Notes
This article was published in the journal, Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability [© IMechE] and is also available at: http://journals.pepublishing.com/content/119859ISSN
1748-006X;1748-0078Language
- en