Concept Selection Using s-Pareto Frontiers

Abstract

We introduce the notion of s-Pareto optimality and show how it can be used to improve concept selection in engineering design. Specie c design alternatives are classie ed as s-Pareto optimal when there are no other alternatives from the same or any other general design concept that exhibit improvement in all design objectives. Further, we say that the set of s-Pareto design alternatives comprises the s-Pareto frontier. Under the proposed approach the s-Pareto frontier plays a paramount role in the concept selection process, as it is used to dee ne and classify concept dominance. Thes-Pareto frontier-based concept selection method can becharacterized as onethat capitalizes on the benee ts of computational optimization during the conceptual phase of design, before a general design concept has been chosen. An introduction to s-Pareto optimality and a method for generating s-Pareto frontiersaredeveloped.Anapproachforusing s-Paretofrontierstoperformconceptselectionisalsopresented.The methods proposed can effectively aid in the elimination of dominated design concepts, keep competitive concepts, and ultimately choose a specie cdesign alternative from theselected design concept. A truss design problem is used to illustrate the usefulness of the method. Nomenclature g = vector of inequality constraints h = vector of equality constraints J = aggregate objective function mi = number of points along Ni Ni = ith vector dee ning the utopia plane n = number of design objectives nx = number of design variables T k = relaxation/slack variable for concept k X P = generic point on the utopia plane x = vector of design variables ± = increment by which feasible space is reduced π = vector of design objectives (or design metrics) π i¤ = ith anchor point π ¤k = optimum design objective value for concept k π si¤ = s-anchor point for the ith objective