A science-based approach to product design theory - Part II: formulation of design requirements and products

The Design Process begins with design requirements and ends with product de scriptions. The design requirements include both structural and performance aspects. The product descriptions deal with the structural aspect of the d esign requirements while the product performances describe the performance aspect of design requirements. In this part of the paper, a set theory-base d representation scheme is proposed to represent design objects in the desi gn process, including design requirements, product descriptions, and produc t performances. This representation scheme can represent the design objects that evolve in dynamic design processes. The entire mathematical scheme is defined based on structural and behavioral properties. Within one uniform scheme, the design objects are represented at different levels of complexit y and abstraction. Several examples are included to explain the scheme and its mathematical formulations. The proposed scheme can be used for science- based studies of product design. (C) 1999 Elsevier Science Ltd. All rights reserved.