INTEGRATED RELIABILITY-ANALYSIS SYSTEM (IRAS)

This paper will introduce a computer aided reliability analysis system , IRAS, which is a Unix-based software package. It provides the follow ing features: a model builder, failure mode effect and criticality ana lysis (FMECA), fault tree synthesis and analysis (FTA) and real time f ault location (RTFL). 1. The model builder allows the creation of reli ability models for production systems, which are able to reflect the i nitiation and propagation of serious deviations outside the production and performance tolerances. The modelling procedure allows hierarchic al modelling. 2. The failure mode effect and criticality analysis (FME CA) option uses the causal trees and cause-consequence diagrams that a re created automatically from the IRAS model data base. The trees can be analysed by the user and the basic events can be grouped according to their criticality, probability and severity. 3. The fault tree anal ysis and synthesis (FTA) option enables the graphical analysis of faul t trees. The generated tree can be trimmed automatically or by the use r. It is also possible to extract the minimal cut-set from the complet e tree. 4. RTFL enables the fast detection of the most probable fault locations in the system, during the continuous measuring of sensors of the production system and comparing the signals with the expected val ues of the stored operational vector. It alarms the user in case of se rious deviations, thus reducing the out of work stage of the system by making quicker and more efficient reaction of the maintenance facilit y operators. The failure searching time reduction results in lower mai ntenance cost.