Case studies in probabilistic design

Deterministic design fails to provide the necessary understanding of the variability associated with the properties of materials, manufacturing tolerances and inservice loading. Probabilistic design offers much potential in this area, providing an effective way of determining product life-time estimates, reducing failure costs and aiding the process of weight optimization in product design, but has yet to be taken up widely by manufacturing industry. In this paper, case studies are used to explore some important probabilistic design concepts and introduce methods that allow reliability performance measures to be assessed for product designs early in the product development process. The methods described are used in conjunction with Failure Mode and Effects Analysis to facilitate the setting of reliability targets for design proposals.