Reliability has long been recognized as a safety constraint in structu
ral engineering. That is, an optimum design should balance both cost a
nd safety. Nevertheless, applications of reliability analysis in recen
t years have been primarily aimed at establishing the basis for code f
actors. Similarly, most optimization studies have used accepted code s
afety factors without introducing reliability as explicit design const
raints. This paper reviews the methodology of component and system rel
iability analysis and examples of their inclusion in optimization appl
ications. The limitations in the explicit use of reliability in optimi
zation are discussed. (C) 1997 Elsevier Science Ltd.