DEALING WITH EXTREME REQUIREMENT VALUES: WHAT METHODS TO DESIGN SCHOOL CHAIRS AND OFFSHORE WIND TURBINES HAVE IN COMMON

Abstract

AbstractMany designs are “driven” by requirements that describe maximum or minimum values of high- variability variables that must be considered. In ergonomics, minima and maxima of anthropometric variables like body height shape the design of a product. Similarly, in structural design, the highest environmental loads that can be expected during the lifetime of a product drive the design. Consequently, a wide range of methods that help designers deal with extreme requirement values has been developed. In this paper, we review these methods and propose a model for the process of dealing with extreme requirement values. The model comprises two broad stages. In the first stage, requirement values are statistically defined and in the second stage, a design is synthesized and evaluated against the requirement values. Throughout the paper, we use two examples: the design of an ergonomic chair and of an offshore wind turbine. We focus on how requirement values are defined for these two products and how they are used throughout the design process. Although these products are vastly different, both are designed by statistically deriving requirement values and then systematically designing against these values.