An Approach Toward Integrating Top-Down and Bottom-Up Product Concept and Design Selection

Abstract

This paper proposes an approach to integrate top-down and bottom-up procedures for product concept and design selection. The top-down procedure identifies relationships between product requirements and design parameters and specifies an acceptable range of design parameters (called a design range) from product specifications and tolerances. Then, within the design range, the bottom-up procedure optimizes design specifications and tolerances in order to minimize a product cost. A product cost is defined as a sum of component costs, each of which is a function of design specifications and tolerances. A concept, with design specifications and tolerances, that minimizes product cost is an optimum concept. The proposed approach is demonstrated using an illustrative example. Sensitivity analysis with respect to the parameters of the product cost illustrates that the shape of design range defines how responsive a product is to uncertainty in cost function parameters relevant to design tolerances.