Effects of alternative wing structural concepts on high speed civil transport life cycle costs

Abstract

An integrated design and manufacturing approach allows economic decisions to be made that reflect the entire system design as a whole. In order to achieve this objective, integrated cost and engineering models were developed and utilized within a focused design perspective. A framework for the integrated product and process design of an aircraft system with a combined performance and economic perspective is described in this paper. This framework is based on the concept of Design Justification using a Design for Economics approach. A production cost model is developed that is sensitive to material and product/process selections for the wing structure. The use of cost/time analyses is described and applied for evaluation of process trades at the sub-component level of design. Results of an Integrated Product/Process Development (IPPD) case study are presented for potential High Speed Civil Transport (HSCT) wing structural concepts. Cost versus performance studies indicate that an aircraft with a hybrid wing structural concept, though more expensive to manufacture than some homogeneous concepts, can have lower direct operating costs due to a lower takeoff gross weight and less mission fuel required.

Numerical Method for Cost-Weight Optimization of Stringer-Skin Panels

“…Structural efficiency is already a tradeoff between maximizing material strength utilization and reducing weight, 45 whereas manufacturing cost is a tradeoff between specified design requirements (within tolerance) and process capability. 46 Equation (29) highlights that the tradeoff can be achieved through the minimization of DOC: DOC = f n(acquisition, fuel burn, maintenance, crew and navigation, ground services)…”

“…28 Marx et al have linked MDO to life-cycle analysis (LCA) by defining high-level objective functions that encompass the lifecycle needs of aircraft, supported by necessary disciplinary models that facilitate the optimization process through the linkage defined by an objective function. 29 In aerospace, LCA tends to be associated with military application, whereas the commercial sector focuses on DOC, being more associated with the cost of transporting a person a number of air miles at as low a cost as possible. There are various DOC models available, which tend to be of a parametric nature, 30,31 that allow tradeoff of design parameters and that can be linked to manufacturing models to couple in the impact on production.…”

“…Marx et al have presented a parametric analytical solution for linking life-cycle needs back to design. 29 They use the case study of a high-speed commercial transporter to investigate the best structural layout for the wing in terms of life-cycle requirements, including chordwise stiffened, spanwise stiffened, and biaxially stiffened structural layouts. A much more detailed analysis platform for the manufacturing cost drivers has been developed by Rais-Rohani, 37 where he incorporates all of the relevant manufacturing issues in terms of parametrically defined complexity factors, including compatibility, complexity, quality, efficiency, and coupling.…”

Life cycle cost modelling as an aircraft design support tool

“…assessing the trade-off between technologies or materials using a life cycle approach). Marx et al [14] linked MDO to life cycle analysis by defining high level objective functions that encompass the life cycle needs of the aircraft. Hackney and Neufville [15] described a life cycle model for performing comparisons of emissions, costs, and energy efficiency trade-offs for alternative fuel vehicles.…”

A stochastic approach to multi-disciplinary aircraft analysis and design

“…IPPD is seen as a management methodology that incorporates a systematic approach to the early integration and concurrent application of all the disciplines that play a part throughout a system's life cycle [11,12]. Best commercial practices in industry have revealed that world class quality and affordable products are achieved through IPPD.…”