This paper explains how value-driven design provides a framework to enhance the systems engineering processes for the design of large systems. It goes on to show that by employing economics in decision-making, value-driven design enables rational decisions to be made in terms of the optimum business and technical solution at every level of engineering design. This paper demonstrates the application of value-driven design to an aircraft propulsion system through two case studies, which were conducted through workshops within Rolls-Royce. Surplus value theory was used to provide a metric that can trade off component designs with changes in continuous and discrete design variables. Illustrative results are presented to demonstrate how the methodology and modeling approach can be used to evaluate designs and select the best value solution.
One of the most ambitious efforts in value-centric design of a military aerospace system undertaken to date has been the parallel development by four performer teams, headlined by major space industry primes, of design tools for fractionated space architectures under DARPA's System F6 program. The goal of the System F6 program is to replace traditional, highly-integrated, monolithic satellites with wirelessly-networked clusters of heterogeneous modules incorporating the various payload and infrastructure functions. Such fractionated architectures can deliver a comparable or greater mission capability than monolithic satellites, but with significantly enhanced flexibility and robustness. In order to design an optimal fractionated architecture, the potential cost penalties due to the overhead of such a design must be balanced against the value enhancement due to improved flexibility and robustness. The first, preliminary design phase of the System F6 program, simultaneously awarded to four competing industry teams led by Boeing, Lockheed Martin, Northrop Grumman, and Orbital Sciences, commenced in February 2008 and included a significant effort for the development, validation, and demonstration of a Value-Centric Design methodology and associated tool suite that can support the design of optimized fractionated satellite systems based on a net lifecycle value metric and a probabilistic distribution thereof. This phase concluded in February 2009 and the Value-Centric Design methodology development to date is documented in a series of papers by the industry performer teams. This paper, from the System F6 Program Office, summarizes the overarching objectives of the Value-Centric Design effort, details and rationalizes the requirements for the methodology, discusses the relationship between Value-Centric Design and the traditional industry-standard systems engineering process, and fills any gaps in the performers' own presentations of their efforts, tools, and results. 1 The views expressed herein are the authors' own and do not necessarily represent those of the Defense Advanced Research Projects Agency, the Department of Defense, or the United States Government. Approved for public release. Distribution unlimited.
Spacecraft * and launch systems are examples of complex products which require a careful balance between competing concerns, such as performance, weight, and reliability, to serve their mission. Complexity requires design by large engineering organizations, so this balance must be achieved across many teams of people working on various components. This paper uses optimization theory to derive a method for distributed optimal design. Each component design team is provided with a separate optimization problem such that, as each team finds the best design solution to their problem, the teams together design the best system. To date, distributed optimal design has been difficult because complex system design spaces have extremely high dimensions over which design objectives are poorly correlated. Instead, this paper proposes that design objectives be expressed as functions in attribute spaces, which have few dimensions and are much smoother than design spaces. Attribute spaces are generated from design spaces by traditional engineering analysis processes. Economic analysis of all parties to spacecraft launch and operation is used to construct a top-level value function on the system attribute space. This function is linearly decomposed into value functions for component attribute spaces. This provides the needed objective functions for distributed optimal design.
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