Value-based decision environment: vision and application

The ever-increasing complexity and environmental constraints associated with aerospace and defense projects are putting pressure on traditional organizational structures for design decision making. No longer can the design problem be assimilated and steered by a single chief engineer. Rather, to find consensus, design involves a complex iterative process between the different specialist committees (weights, aerodynamics, structures, cost, etc.). Furthermore, there is a growing need to take into account the life-cycle implications of low-level design decisions in addition to their more direct implications on performance. The Decision Environment for Complex Designs project at the University of Southampton aims to explore how the design process may be streamlined under these circumstances. The case study presented here centers around a maritime surveillance unmanned aerial vehicle for search and rescue tasks, developed in association with the U.K. Coastguard. The focus is on “value-driven” design and how advances in software engineering, rationale capture, operational simulation, and rapid prototyping can be leveraged to create an integrated design suite that allows the rapid design and manufacture of low-cost civilian unmanned aerial vehicles

Towards a framework for value-driven design in civil aerospace systems: a case study

Value-Driven Design combines economic theory, systems engineering and multi-disciplinary analysis and optimisation to help improve the design of complex systems. An approach to Value-Driven Design is the surplus value theory, which utilises financial measures to act as a scoring function for how much a design is worth to the operation of an entire system. This is beneficial for design decisionmaking in system trades and technology evaluation. In this paper, a Value-Driven Design methodology is introduced using the surplus value metric and applied to an aerospace system case study

Utilising dynamic factory simulation to improve unit cost estimation and aid design decisions

Utilising dynamic simulation methods to estimate manufacturing resources, can improve unit cost estimation and aid design decisions. This paper introduces a framework specification that combines Computer Aided Design (CAD), Computer Aided Process Planning (CAPP) and Discrete Event Simulation (DES) technologies. The framework is used to aid a design team in understanding the consequences of design decisions in terms of cost and manufacturing resources, by returning unit cost and manufacturing based results, directly to the design team, within the design environment. Dynamic Resource Estimation System (DRES) is a system being developed to implement the framework and is presented in this pape

The inertia problem: implementation of a holistic design support system

This paper describes and reflects on the implementation of a Knowledge Based Holistic Design Support System – termed “HolD” – into a business environment.The paper introduces the rationale and development behind the system, a consciously different approach to traditional knowledge based systems in engineering in order to meet the requirements of a small business producing bespoke, low volume products.Typical knowledge based engineering systems rely on explicitly codified knowledge which often support product optimisation rather than creative design activities. Such a system would provide little benefit to a business producing bespoke products. Instead, the system presented here, supports the creativity of designers through codified tacit knowledge input by designers as meta-data for past designs.The problem of individual inertia in adopting the system and sharing knowledge was approached early in the construction of the system. The steps taken to lower user barriers and encourage day-to-day use are detailed, including the design of a multi-stage input process designed to interact at key stages of users' existing processes.The immediate results after a 6 month trial period are presented and the results show slower than anticipated usage. In particular designers were found to be reluctant to input detailed information beyond common identifying data and did not attempt to seek information from the system. The reasons for this slower usage are discussed and possible solutions presented. The paper therefore provides industrial based evidence of the inertia encountered when implementing a knowledge system and argues that technology alone is insufficient to overcome this inertia

Cost modelling for aircraft design optimization

This paper summarizes work that has been carried out to date on the Implied Cost Evaluation System (ICES) research project. This is an EPSRC-funded project that is sponsored by BAe (Airbus) and Rolls Royce (Defence Europe). The paper identifies the need for detailed and reliable cost information in order to optimize a product design. This is illustrated with reference to recent cost modelling work carried out in support of preliminary designs for the proposed Airbus A380 600 seat aircraft. The merits of the various alternative approaches are identified and the genealogy of current systems and techniques is briefly outlined. It is argued that current tools lack a number of key features and capabilities. In particular, it is suggested that current cost modelling tools are not able to deal with the multiplicity of levels of abstraction associated with an emerging design. Furthermore, there is no generally accepted method for expressing the uncertainty associated with a cost estimate in a rigorous and systematic way. This paper outlines some of the initial development work on the ICES project. This concerns the development of an object-oriented product data structure that supports multiple levels of abstraction, statistical modelling and decision support construct