Multidisciplinary optimization of the high-speed civil transport

Abstract

This paper describes a procedure, developed over several years at Virginia Tech, for the combined aerodynamic-structural design optimization of a high-speed civil transport (HSCT). The computational challenge associated with the optimization is the focus of the work and it is addressed by two techniques. First, we developed efficient parameterization of the design, which describes the wing, fuselage, tails, nacelle geometries, and mission profile with only 28 design variables. Second, we used a variable-complexity modeling (VCM) technique, which combines simple and complex models to construct various discipline approximations for use during the optmization process. Simple models for predicting aerodynamic performance and structural weight are conceptual-design-level methods. The more complex models are panel methods and finite-elementbased structural optimization. The VCM approach allows us to combine the computational efficiency of the simpler models with the accuracy of the more complex ones. Several examples are used to demonstrate design trade-offs for the HSCT.

Variable-complexity response surface approximations for wing structural weight in HSCT design

“…For the optimal designs produced using RS2, values for W b G are well below the 20,000 lbs which defines the lower limit of wing bending material weight values in The aforementioned limits on W b are based on previous work where optimal HSCT designs were significantly heavier [3]. A better constraint on W b for this study might have been 15,000 lbs < W b < 60,000.…”

“…The approximate range is evaluated for each design using simple methods to estimate total drag on the aircraft [3]. Because of the nature of this calculation, designs having an approximate range greater than 5,000 n mi.…”

“…Detailed analysis methods are employed at the beginning of each cycle, while simple analyses, scaled to match the initial detailed results, are performed in subsequent calculations during each cycle [2,3]. A typical HSCT design requires approximately twenty-five cycles until an optimal configuration is identified.…”

Variable-Fidelity Aerodynamic Shape Optimization

“…For example, the coupling of the aerodynamic load with the wing structure by way of structural analysis [31]. This is referred to as multidisciplinary design and optimization (MDO).…”

“…In SBO, the accurate but computationally expensive high-fidelity CFD simulations are replaced-in the optimization process-by a cheap surrogate model. In this chapter, we provide a review of some representative works on aerodynamic shape optimization relating both to the direct [1,4,10,[12][13][14][15][16][17][18][19][20][21] and the surrogate-based optimization approaches [29,[31][32][33]. In particular, the main emphasis of the chapter is on the SBO approach exploiting surrogate models constructed from corrected physicsbased low-fidelity models [26,[34][35][36][37][38].…”