Evaluation of System Evolvability Based on Usable Excess

Allen, Jeffrey D.; Mattson, Christopher A.; Ferguson, Scott

doi:10.1115/1.4033989

Cited by 15 publications

(3 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…length, area, and volume (space) and structural strength. Several authors have quantified excess (see for example [23], [24]) and shown that it is fungible (i.e. different types could be traded off with each other) [16].…”

Section: Redundancymentioning

confidence: 99%

Evolvability and design reuse in civil jet transport aircraft

Heerden

Guenov

Molina-Cristóbal

2019

Progress in Aerospace Sciences

View full text Add to dashboard Cite

A comprehensive investigation of evolvability and design reuse in new and historical civil jet transport aircraft was undertaken. The main purpose was to characterise the techniques and strategies used by aircraft manufacturers to evolve their designs. Such knowledge is essential to devise improved design methods for promoting the evolvability of new aircraft. To perform the study, jet aircraft from three large western manufacturers (Boeing, Airbus, and McDonnell Douglas) were investigated in depth. The academic and industrial literature was combed to find descriptions of design reuse and change across each major model of all three manufacturers. The causes and effects of the changes are explored, and the amenability of the different airframes to change are discussed. The evolution of the payload and range capabilities of the different aircraft was also investigated. From these studies, it was found that the initial approach to derivative designs appears somewhat ad hoc and that substantial modifications were devised in quick succession to increase both range and capacity. From the 1970s, two distinguishable patterns started to appear-a 'leap and branch' and a 'Z' pattern. The leaps correspond to major changes in both propulsion and airframe, whereas the branches are simple 'stretches' or 'shrinks'. The Z pattern, also documented by other authors, is a progressive increase in range, followed by a simple stretch, and then another increase in range. Design changes were investigated further by grouping them according to the assumed payload-range objectives set for the derivatives. Finally, the maximum changes found for salient geometrical design parameters amongst all the aircraft surveyed were documented. Developing methods to support the creation of leaps (especially across configurations) appears to be one of the most promising avenues for future research.

show abstract

Section: Redundancymentioning

confidence: 99%

Evolvability and design reuse in civil jet transport aircraft

Heerden

Guenov

Molina-Cristóbal

2019

Progress in Aerospace Sciences

View full text Add to dashboard Cite

show abstract

“…This type of system attribute has been labeled "excess", and research has begun to explore what excess is and what it's properties are [13][14][15][16]. In this paper excess is defined as a modified version of that found in Allen [16] and Tackett [15] to be the quantity of usable surplus of a system resource that is likely to be prohibitively expensive to increase with inservice design changes. A prohibitive cost would be one for which the system decision maker would prefer performance degradation or retirement to configuration change.…”

Section: Introductionmentioning

confidence: 99%

“…This line of inquiry is important to CES design because it addresses one of the aspects of system design that may limit its lifetime. One example cited in literature is that of a nuclear powered aircraft carrier [16]. The electrical power generated by the carrier is a limiting factor for the addition or modification of systems.…”

Section: Introductionmentioning

confidence: 99%

A Case Study of Evolvability and Excess on the B-52 Stratofortress and F/A-18 Hornet

Long

Ferguson

2017

Volume 4: 22nd Design for Manufacturing and the Life Cycle Conference; 11th International Conference on Micro- And Nanosystems

View full text Add to dashboard Cite

The moment a system is put into service it begins to lose value as technological and societal changes accrue while the system is frozen in the state it was constructed. System decision makers are faced with the choice of accepting a decline in performance, updating the design, or retiring the system. Each time a decision maker faces these alternatives, the value of the available options must be evaluated to determine the preferred course of action. A design that can adapt to changes with minimal cost should provide more value over a longer period than a system that is initially less costly, but less adaptable. This is especially desirable for systems that have large initial costs and/or a lengthy development cycle. The purpose of this paper is to evaluate the United States Air Force (USAF) B-52 Stratofortress and the United States Navy (USN) F/A-18 Hornet to characterize the changes in desired capabilities and what system attributes allowed them to either successfully adapt or prevented them from adapting. These observations allow the development of heuristics that designers can use during system design to enhance system lifetime value.

show abstract

Mechanisms to support changeability during sustainment: Modularity, excess, and operations

Singh,

Szajnfarber

2024

Systems Engineering

View full text Add to dashboard Cite

Complex engineered systems face protracted design cycles and indefinite lifetimes, leading to discrepancies between expected and actual operating conditions. The field of design for changeability has focused on developing strategies to cope with these discrepancies. Literature has implicitly assumed that future changes can be predicted by system designers, but this assumption does not match observed reality. Often, systems must be modified in unexpected ways to maintain value, limiting the usefulness of standard change mechanisms. To understand how unexpected changes are implemented in practice, we studied the C‐130, a setting where one platform performed many missions, and close air support in Desert Storm, a setting where many platforms performed one mission. Through this examination, we find that excess and operator change are key mechanisms for changeability that have been largely ignored by literature. Excess can enable additions to systems without having to remove or swap subsystems out. It is also a critical enabler of modular changes during the operational phase. Operator changes are non‐form changes driven by system users who change how their systems are used to gain new capabilities rather than relying on changes to the form of the system. This paper also studies the relationship between these mechanisms to shed light on how changeability is achieved in practice, building the foundation for future work to study tradeoffs of implementing valuable excess during design.

show abstract

Evaluation of System Evolvability Based on Usable Excess

Cited by 15 publications

References 41 publications

Evolvability and design reuse in civil jet transport aircraft

Evolvability and design reuse in civil jet transport aircraft

A Case Study of Evolvability and Excess on the B-52 Stratofortress and F/A-18 Hornet

Mechanisms to support changeability during sustainment: Modularity, excess, and operations

Contact Info

Product

Resources

About