Fault Tree Analysis Using Hybrid Events for Accurate Reliability Assessment
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Solution Overview
Problem
Current Fault Tree Analysis (FTA) methods require manual expert intervention, leading to time-consuming and error-prone calculations, especially when dealing with detected and undetected failure modes, making it challenging to accurately assess system reliability, particularly after design changes.
Innovation Solution
The introduction of hybrid events that represent both latent and evident failure modes, allowing for automated probability calculations using failure rates, coverage, and inspection periods, reducing manual input and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual expert intervention is used to calculate coverage of failure modes, then accuracy of probability calculation can be maintained, but time consumption increases significantly and human errors occur
Solution Approach 1:
The system performs self-service by automatically calculating coverage of failure modes using predefined algorithms and data from FMECA results, eliminating the need for manual expert intervention. The automated system processes failure rate data, coverage percentages, and inspection periods to compute probability values without human input, thereby maintaining accuracy while dramatically reducing time consumption and eliminating human errors.
2Reliability
If manual expert intervention is used to create OR Gates with modified Failure Rate, then accurate probability assessment is possible, but the process becomes practically impossible after design changes
Solution Approach 1:
The system implements dynamics by enabling automatic recalculation of coverage and probability values whenever design changes occur. The automated system dynamically updates the FTA model by processing new FMECA results and recalculating all dependent probability values without requiring manual reconfiguration of OR Gates or expert intervention, thereby maintaining both accuracy and adaptability to design changes.
Solution Approach 2:
The system applies preliminary action by pre-defining the computational algorithms and data relationships needed for coverage calculation before design changes occur. The automated framework is预先 configured with the logic for processing failure rate data, coverage percentages, and inspection periods, allowing it to immediately and accurately recalculate probabilities when new design data becomes available, eliminating the need for manual re setup.
3Extent of automation
If hybrid events representing both latent and evident failure modes are used, then automated probability calculation becomes possible, but complexity of event representation increases
Solution Approach 1:
The system merges latent and evident failure modes into a unified hybrid event representation. Instead of treating them as separate events requiring separate analysis, the hybrid event combines both failure mode types into a single computational entity that automatically processes both detected and undetected failures using integrated algorithms, thereby enabling automation without proportionally increasing complexity.
Solution Approach 2:
The hybrid event serves multiple functions simultaneously: it represents both latent and evident failure modes, stores combined failure rate data, and performs integrated probability calculations for both failure types. This multi-functionality reduces the overall number of separate events and calculations needed in the FTA model, enabling automation while actually simplifying the overall event structure compared to treating each failure mode separately.
Data Source
AI summary
A method for fault tree analysis (FTA) of a system, the method may include (i) preforming FTA of the system using multiple hybrid events to provide a FTA result, wherein each hybrid event represents both latent failure modes and evident failure modes; and (ii) responding to the FTS result.