A knowledge-based system integrated with numerical analysis tools for aircraft life-cycle design

Abstract

An integrated design and manufacturing approach allows economic decisions to be made that reflect an entire system design as a whole. To achieve this objective, we have developed and utilized integrated cost and engineering models within a focused design perspective. A framework for the integrated design of an aircraft system with a combined performance and economic perspective is described in this article. This framework is based on the concept of Design Justification using a Design-for-Economics approach. We have developed a knowledge-based system that can be used to evaluate aircraft structural concept material and process selections. The framework consists of the knowledge-based system, integrated with numerical analysis tools including an aircraft performance/sizing code and a life-cycle cost analysis code. Production cost estimates are applied for evaluation of process trades at the subcomponent level of design. Life-cycle cost estimates are used for evaluation of process trades at the system level. Results of a case study are presented for several advanced wing structural concepts for a future supersonic commercial transport aircraft. Cost versus performance studies indicate that a high-speed civil transport 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 take-off gross weight and less mission fuel required.

Cost optimization of composite aircraft structures including variable laminate qualities

“…It was concluded that the compressive strengthσ c degrades exponentially. In the context of isotropic materials, the equationσ =σ max e Bvp (6) has elevated to describe this behavior, whereσ max is the strength at zero porosity, v p is the volume fraction of pores and B is an empirical constant that depends on orientation, shape and size of the pores.…”

“…The adjustment of the allowables due to porosity was estimated according to Equation (6). The value of B = −3.14 was adopted from Uhl et al [23] who performed a number of test series for a 16 ply quasi-isotropic carbon/epoxy laminate.…”

“…Attempts for a combined cost/weight optimization have been done by Geiger and Dilts [1], Heinmuller and Dilts [2], Kassapoglou [3][4][5], Marx et al [6], Gantois [7], the Rolls-Royce's DATUM project [8], Park et al [9], Edke and Chang [10], and Curran et al [11]. In particular, Kelly and Wang [12], Wang et al [13], Curran et al [14], and Kaufmann et al [15] incorporated the idea of a weight penalty; this weight penalty was applied to balance the tradeoff between manufacturing cost and structural weight.…”

Experimental Detection and Quantitative Interrogation of Damage in a Jointed Composite Structure

“…The cost for these maintenance practices totals up to 11% of the total life cycle cost of the aircraft [6]. For a fleet of 108 Boeing 737 airplanes, this amount exceeds $4 billion over a 25 year life cycle [7].…”

Discourse analysis based segregation of relevant document segments for knowledge acquisition

“…In different stages of a product's life cycle, knowledge is generated and, where possible, recorded. Such knowledge is useful when planning products (Marx et al, 1998). This knowledge can form the basis for design (computer-aided design models and process descriptions); it can also be used to avoid decisions that led to issues in the product's life cycle (as reflected in change requests or incident reports).…”