Reliability Modeling That Reflects How Systems Actually Fail
Practical application of Reliability Block Diagrams (RBD), Fault Tree Analysis (FTA), and Operator Error/Atack modeling to support engineering design, risk analysis, and operational decision-making.
40+ years of engineering experience across multidisciplinary systems and complex operations.
Why Reliability Modeling Often Falls Short
Reliability engineering uses methods such as Reliability Block Diagrams (RBD) and Fault Tree Analysis (FTA) to evaluate system performance, failure modes, and risk. Accounting for operator error and human reliability is critical in modern engineering systems.
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​Many organizations apply reliability methods as isolated tools rather than integrated decision-support systems.
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As a result:
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- Models do not reflect how systems actually operate
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Human interaction is oversimplified or ignored
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Failure modes are incomplete or disconnected
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Outputs are difficult to defend or act on
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Reliability modeling should support real decisions, not just produce diagrams.​​
RBD vs Fault Tree Analysis — Use the Right Tool for the Right Problem
RBD models system success based on the functional relationship between components.​
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Key Strengths​
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- Clear system-level view
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Simplifies complex architectures
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Useful for availability and success-path modeling
Limitations
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Does not explicity model failure causation
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Limited representation of human error
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Assumes success conditions rather than failure drivers​​
FTA models system failure based on causal relationships between events.​
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Key Strengths​
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- Explicit modeling of failure pathways
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Strong support for risk and safety analysis
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Ideal for complex causal chains
Limitations
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Can become complex quickly
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Requires deeper modeling discipline
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Less intuitive at system-level architecture view​​