System Engineering Management, 5th Edition

Chapter 5Design Review and Evaluation

System design is an evolutionary process, progressing from an abstract notion to something that has form and function, is fixed, and can be reproduced in specified quantities to satisfy a designated consumer need. Initially, a requirement (or need) is identified. From this point, design evolves through a series of phases; that is, conceptual design, preliminary system design, and detail design and development, as illustrated in Figure 1.13.

As the design progresses, there are natural degrees of system definition. Requirements are defined, leading to a “functional” baseline. This includes the definition of operational requirements and the maintenance concept, trade-off study reports and the results of the feasibility analysis, the identification of technical performance measures (TPMs), and the system specification (Type A). Functional analysis and requirements allocation are accomplished, the results of which are defined through an “allocated” baseline. This baseline may be defined through a combination of development, process, product, and/or material specifications (Types B, C, D, and E) as applicable. This configuration is progressively expanded, through numerous iterations, until a “product” baseline is defined, and so on. These natural phases of system definition are reflected by the activities and milestones identified in Figure 1.27.

In viewing the overall design process, the necessary checks and balances must be incorporated to ensure ...