Failure modes and effects analysis of complex engineering systems using functional models

A set of models developed by Chittaro for fault diagnosis is extended to represent more complex engineering systems. A novel methodology for qualitative reasoning about behaviour change has been developed for the purpose of failure modes and effects analysis to cope with complete and partial failure modes. The method is demonstrated on an electrically driven gear pump. A further extension is the ability to cope with control systems by distinguishing the function of two closed loop control schemes. Different types of failure of the control scheme can be identified by analysing three different responses of the faulty plant. This method is demonstrated on a manufactured aerospace component called a fuel-metering unit controlled by a negative feedback control scheme. (C) 1998 Elsevier Science Limited. All rights reserved.