Handbook of Reliability, Availability, Maintainability and Safety in Engineering Design - Part 15 studies the combination of various methods of designing for reliability, availability, maintainability and safety, as well as the latest techniques in probability and possibility modelling, mathematical algorithmic modelling, evolutionary algorithmic modelling, symbolic logic modelling, artificial intelligence modelling, and object-oriented computer modelling, in a logically structured approach to determining the integrity of engineering design. . | Analytic Development of Reliability and Performance in Engineering Design 123 Computation only X and only Y and G only Range G X Y Flow corners Q n m3 min Flow range Q n flow 54 m3 h Propagation result Flow Q all-parts only flow 54 Elimination condition only X1 and only X2 and Not X1 nX2 Subset interval System requirement X1 flow 60 m3 h Subset interval X2 flow 54 m3 h Computation X1 nX2 flow 54 m3 h Elimination result Condition Not X1 n X2 -Irtie Description With the labelled interval of displacement between x 10 3 and 6 x 10 3 cubic metre per revolution and the labelled interval of RPM in the interval of 75 to 150RPM the pumps can produce flows only in the interval of to 54m3 h. The elimination condition is true in that the labelled interval of flow does not meet the system requirement of System requirement X1 flow 60 m3 h Subset interval X2 flow 54 m3 h Labelled Interval Calculus in Designing for Reliability An approach to designing for reliability that integrates functional failure as well as functional performance considerations so that a maximum safety margin is achieved with respect to all performance criteria is considered Thompson et al. 1999 . This approach has been expanded to represent sets of systems functioning under sets of failure and performance intervals. The labelled interval calculus LIC formalises an approach for reasoning about these sets. The application of LIC in designing for reliability produces a design that has the highest possible safety margin with respect to intervals of performance values relating to specific system datasets. The most significant advantage of this expanded method is that besides not having to rely on the propagation of single estimated values of failure data it also does not have to rely on the determination of single values of maximum and minimum acceptable limits of performance for each criterion. Instead constraint propagation of .
