Session: DAC-16-01-Platform Architecture and Product Family Design

Paper Number: 91348

91348 - Requirements Mapping of a High-Powered Rocket System to Explain Solution Similarities Across Generations 

Designers have historically used existing solutions as a baseline for modifying and improving the next generation solution. However, it is also possible that certain design solutions are preferred and pursued by designers irrelevant of previous design history, suggesting that there is some dominant system architecture for a given set of requirements. While the reason for system architecture similarities can never be determined with certainty without consulting designers, it is possible to speculate about why design decisions might have been made, especially when certain system architectures and design elements have dominated a space for so long. The NASA SL Challenge serves as a compelling area for study, given that NASA SL vehicle and recovery performance requirements are similar from year to year, while payload integration and payload function requirements differ each year. Student design teams are tasked with designing a new launch vehicle and payload each year to meet all of the requirements. Despite changes in payload requirements, some teams’ vehicle architectures remain largely unchanged from year to year, prompting a question of whether these design solutions are inherently preferred based on the nature of the design problem or if they are just based on the reuse of previous design solutions. To investigate this question, DSM-style requirements mappings are generated to relate system requirements to vehicle elements. These requirements mappings are then translated into tree structures for ease of analysis. These mappings are analyzed to determine why certain design solutions may have been preferred based on entanglement between requirements, and insights from the mappings are supported by a NASA SL team’s design history. Ultimately, the mappings were used to identify areas of tension between requirements and independent variables within system architectures. Analysis of the mappings also suggests that certain elements of system architectures may be more or less dominant based solely on the design problem definition. As an extension of this, it is possible that the requirements mappings could be used to identify preferred architectures for a given design problem in the conceptual design phase. Finally, based on observations made in this case study, there is evidence that requirements mappings could help guide the strategic placement of excess in a system. Future work is needed to determine how requirements mapping could support the placement of excess and to explore how to conduct requirements mapping in a streamlined and efficient way.

Presenting Author: Lindsey Jacobson North Carolina State University

Presenting Author Biography: Lindsey is an Undergraduate research assistant at NC State University.

Authors:

Lindsey Jacobson North Carolina State University
Scott Ferguson North Carolina State Univ