Cost Factors Contributing to the Choice of Aerospace Advanced Materials
The materials selection process for the most recently proposed military and civil aircraft has centred substantially around the use of advanced carbon composites versus conventional high strength aluminium alloys. The former material type has been selected for use in increasing proportion. For example, Airbus’s A400M is 35% advanced composite by weight; the JSF is 40%; the Boeing 787 Dreamliner is circa 50%; the proposed Russian MS21is 45%; the A350 XWB is 52% and the Bombardier C-Series is more than 50%.
The decision-making process associated with materials selection is complex by nature and differs from one original equipment manufacturer to another. It is of necessity a multi-disciplinary process and focuses on classic trade-off compromises that involve cost, weight, structural strength, aerodynamic smoothness, durability, maintainability and ease of repair. This paper discusses the relationship between these functionalities, with a particular emphasis on cost, and in doing so seeks to identify those specific applications of advanced composites that are least cost effective. With this particular emphasis, the paper addresses ideally composite manufacturing solutions, so-called “black metal” designs and why in certain instances major metallic components have been retained in otherwise composite constructions. For example, the main wing box where the bulk of the wing strength resides and which traditionally forms the fuel tank on civil aircraft is comprised of carbon composite top and bottom skins, carbon composite front and rear spars and yet retaining metallic inter-spar ribs for the latest commercial aircraft types. The paper discusses the topic of how carbon composites can ever be cost competitive against conventional high strength aluminum alloys at up to twenty times the raw material purchase their costs, addressing such subjects as manufacturing processes and material utilization. Finally in the topical area of total life cycle cost, the issue of disposal and recycling of advanced composites at the time of aircraft retirement is addressed.
This is an uncompromisingly practical paper which challenges design decisions that have already been made.
Business Consultant, C.I. Consultants Ltd , Belfast UK
Paul Shields is a business consultant whose career in the aerospace industry spans over thirty years. After studying mechanical engineering and then management at post-graduate level he has held management positions in various disciplines including cost estimating, commercial and contracts, programme management and customer support.
He is presently a director of C.I. Consultants Ltd, on behalf of which Paul services the aerospace and defence sector in all areas of strategic development, supply chain management, bidding, cost estimating and contract negotiation, including specialist training in each of these areas. C.I.C. has a client base in UK, France, Canada and US.
Paul is a regular guest lecturer in Cost Engineering, Systems Engineering, Cost and Schedule Risk Analysis and Affordability at Cranfield University, England and at Queens University Belfast, Northern Ireland and is also an undergraduate external examiner. He is a member of the Association of Cost Engineers (A Cost E), the Institute of Business Consultants (IBC) and the Independent Consultants and Advisors Group – Northern Ireland (ICAGNI).