Handbook of Reliability, Availability, Maintainability and Safety in Engineering Design - Part 8 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. . | Theoretical Overview of Reliability and Performance in Engineering Design 53 Fig. Power train system reliability of a haul truck Komatsu Corp. Japan Fig. Power train system diagram of a haul truck 54 3 Reliability and Performance in Engineering Design Table Power train system reliability of a haul truck Output shaft assembly Transmission sub-system Power train system No. of components 5 50 100 Group reliability Output shaft assembly reliability 5 Transmission sub-system reliability 50 Power train system reliability 100 components are considered to have the same reliability of . The reliability calculations are given in Table . The series formula of reliability implies that the reliability of a group of series components is the product of the reliabilities of the individual components. If the output shaft assembly had five components in series then the output shaft assembly reliability would be five times the product of . If the torque converter and transmission assemblies had a total of 50 different components belonging to both assemblies all in series then this sub-system reliability would be 50 times the product of . If the power train system had a total of 100 different components belonging to different assemblies some of which belong to different sub-systems all in series then the power train system s reliability would be a 100 times the product of . The value of a component reliability of implies that out of 100 000 events 99 999 successes can be expected. This is somewhat cumbersome to envisage and therefore it is actually more convenient to illustrate reliability through its converse unreliability. This unreliability is basically defined as Unreliability 1 Reliability . Thus if component reliability is the unreliability is . This implies that only one failure out of a total of 100 000 events can
