A graphical model-based reliability estimation tool and failure mode and effects simulator

A new graphical reliability estimation tool, Reliability Performance Module (RPM), is described. RPM combines the features of a powerful reliability tool, Reliability Estimation System Testbed (REST), developed at NASA Langley, with the convenient graphical modelling and simulation capabilities of an off-the-shelf commercial software package, Block Oriented Network Simulator (BONeS), from the Alta Group of Cadence Design Systems. In order to estimate the reliability of a system, the built-in BONeS graphics capabilities are used to describe the system, and the embedded REST execution engine produces a reliability analysis automatically. An additional benefit of this approach is that a detailed failure modes and effects analysis can be derived by using the simulation capabilities of the tool. The usage of and output from RPM is demonstrated with an example system. As compared to our current design process, RPM promises to reduce overall modelling and analysis time, provide better documentation, make trade studies easier, create reusable modelling components and subsystems, and provide the integration of reliability and timing analysis necessary to guarantee the safety of critical real-time systems. Future work will concentrate on producing a more seamless integration of the reliability and timing analyses. Additional planned enhancements include a distributed (parallel) processing mode, and availability and phased-mission analysis capabilities.