Application of Value-Driven Design to Commercial AeroEngine Systems

Abstract

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.

Model-Driven Decision Arena: An Aerospace Case Study

“…VDD exploits quantitative analytical models to perform tradespace studies on alternative design configurations (e.g., McManus, 2007), so to enable optimization of the different parts of the sub-system. Intuitively, these models take the form of monetary optimization functions ) based on Net Present Value (NPV) or Surplus Value (SV) approaches, the latter often being used as surrogate object for long-term profitability associated with a given design concept (see : Curran et al, 2010;Fanthorpe et al, 2011;Cheung et al, 2012). The main argument in favor of a VDD approach is found in several case studies from SE research (see Collopy, 2012;Gorissen et al, 2014) that shows how requirements hinder a systematic exploration of design alternatives, causing the most valuable ones to be rarely identified.…”

A value-focused approach for establishing requirements’ specification of commercial aircraft

“…In this framework, a system value model is a multi-attribute utility function rather than the surplus value model deployed in the original investigation 9 . The system value model is rather a combination of customer (airlines are the only customers and fare paying passengers are not considered here) value model and interface model that models the functional relationships between customer needs and top-level aircraft requirements.…”

“…Figure 1. A schematic illustration of VDD in context of CRESCENDO 9,17 One innovative aspect of the work package is how to build three types of value models from initial customer statements of needs, expectations, goals, and constraints in parallel with the traditional RE process, which ensures that the developed aircraft reflects customer value. It includes:…”

“…For instance, aircraft design alternatives are traditionally evaluated in terms of recurring and non-recurring costs by aircraft manufacturers and direct/indirect operating costs by airlines or other operators. More recently, surplus value (or profit) based system value models have been proposed to optimize aero-engine and fuselage designs in the value-driven design community, which enables surplus value produced from commercial aircraft operations as the single objective function or decision criterion 9,10 . Evidently, cost or profit is one special and critical dimension of value, but there are other dimensions, such as performance, safety, reliability, cabin comfort and many others.…”

Value-Driven V-Model: From Requirements Analysis to Acceptance Testing

“…Value-driven approach of software development is similar to the concept of user-centered design. Value-driven approach focuses on the high-level needs or system features that is prioritized by stakeholders based on the perceived business value [27], [28].…”