Reliability Analysis During the Design Phase

Abstract

Reliability analysis during the design and development of complex components, equipment and systems is important to detect and eliminate reliability weaknesses as early as possible and to perform comparative studies. Such an investigation includes failure rate and failure mode analysis, verification of the adherence to design guidelines, and cooperation in design reviews. This chapter presents method and tools for failure rate and failure mode analysis of complex equipment and systems considered as nonrepairable up to system failure (except for Eq. (2.48)). Estimation and demonstration of a constant failure rate λ or of MTBF for the case MTBF ≡ 1/λ is in Section 7.2.3. After a short introduction, Section 2.2 deals with series - parallel structures. Complex structures, elements with more than one failure mode, and parallel models with load sharing are investigated in Section 2.3. Reliability allocation with cost considerations is discussed in Section 2.4, stress / strength and drift analysis in Section 2.5. Section 2.6 deals with failure mode and causes-to-effects analyses, and Section 2.7 gives a checklist for reliability aspects in design reviews. Maintainability is considered in Chapter 4, together with spare parts reservation and maintenance strategies with cost considerations. Repairable systems are investigated in Chapter 6 including complex systems for which a reliability block diagram does not exist, imperfect switching, incomplete coverage, reconfigurable systems, common cause failures, as well as an introduction to network reliability, BDD, ET, dynamic F T, Petri nets, computer-aided analysis, and human reliability. Risk management for repairable systems is considered in Section 6.11. Design guidelines are given in Chapter 5, qualification tests in Chapter 3, reliability tests in Chapters 7 and 8. Theoretical foundations for this chapter are in Appendix A6.