Relative Reliability Risk Assessment Applied to Original Designs During Conceptual Design Phase

Abstract

Systematic evaluations of concept designs involve consideration of a range of criteria. Interaction with industry supports the view that reliability is a major criterion during product design. Although there are a few methods to predict reliability in the initial phases of design most of them are only applicable to adaptive designs. In this paper, the concept of relative reliability risk assessment for original designs is introduced, where information availability is less, to calculate reliability. The function structures of the product under consideration are considered and analytic hierarchy process is applied using verbal assessments for relative measurements. The weight assigning technique used is the entropy method. A final value of R3I (relative reliability risk index) is calculated and the idea of concept functionality graphs is presented. This method is applied to an example of a seat suspension for an off-highway vehicle and the results are discussed. For validation, an industry example of transmission design is considered for one of the product models of a truck produced by Terex in Scotland. The results show that the method helps to highlight the concepts that are relatively stronger in terms of reliability. The method is also confirmed by the validation example.