Dimitri N. Mavris

A CONCEPT EXPLORATION METHOD FOR DETERMINING ROBUST TOP-LEVEL SPECIFICATIONS

In the early stages of design of complex systems, it is necessary to explore the design space to determine a suitable range for specifications and identify feasible starting points for design. A Robust Concept Exploration Method (RCEM) is developed to improve efficiency and effectiveness while making these early design decisions. An integrated design process is used to introduce quality consideration into the choice of robust top-level design specifications. This is achieved by integrating Taguchis robust design principles and the Response Surface Methodology (RSM) into one multiobjective mathematical construct, namely, the compromise Decision Support Problem. The proposed approach is demonstrated for determining top-level specifications for airframe geometry and the propulsion system in the design of an integrated airframe/propulsion High Speed Civil Transport (HSCT) system. The focus in this paper is on illustrating the approach rather than on the results per se.

Robust Design Simulation: A Probabilistic Approach to Multidisciplinary Design

Most current paradigms in multidisciplinary design analysis and optimization fail to address the presence of uncertainty at numerous levels of the design hierarchy and over the design process time line. Consequently, the issue of robustness of the design is neglected. An approach for the determination of robust design solutions is outlined in this paper, where uncertainty is quantified and its effects mitigated. The robust solution is found through maximization of the probability of an overall figure of merit achieving or exceeding a specified target. The proposed methodology is referred to as robust design simulation (RDS). Arguments as to why a probabilistic approach to aircraft design is preferable over the traditional deterministic approaches are presented, along with a step-by-step description of how one could implement the RDS. An application involving the high-speed civil transport is conducted as a case study to demonstrate the proposed method and to introduce an evaluation criterion that guarantees the highest customer satisfaction.

Next Generation More-Electric Aircraft: A Potential Application for HTS Superconductors

Sustainability in the aviation industry calls for aircraft that are significantly quieter and more fuel efficient than todays fleet. Achieving this will require revolutionary new concepts, in particular, electric propulsion. Superconducting machines offer the only viable path to achieve the power densities needed in airborne applications. This paper outlines the main issues involved in using superconductors for aeropropulsion. We review our investigation of the feasibility of superconducting electric propulsion, which integrate for the first time, the multiple disciplines and areas of expertise needed to design electric aircraft. It is shown that superconductivity is clearly the enabling technology for the more efficient turbo-electric aircraft of the future.

A Stochastic Approach to Multi-disciplinary Aircraft Analysis and Design

Presented at the 36th Aerospace Sciences Meeting and Exhibit, Reno, NV, January 12-15, 1998.

Uncertainty Modeling and Management in Multidisciplinary Analysis and Synthesis

Presented at the 38th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, January 10-13, 2000.

Application of Probabilistic Methods for the Determination of an Economically Robust HSCT Configuration

Presented at the 6th AIAA/NASA/USAF/ISSMO Symposium on Multidisciplinary Analysis and Optimization, Bellevue, WA, September 4-6, 1996.

Forecasting Technology Uncertainty in Preliminary Aircraft Design

Presented at the 4th World Aviation Congress and Exposition, San Francisco, CA, October 19-21, 1999.

A Probabilistic Approach to Multivariate Constrained Robust Design Simulation

Presented at the 2nd World AviationCongress and Exposition, Anaheim, CA, October 13-16, 1997.

Design Optimization of a Truss-Braced-Wing Transonic Transport Aircraft

the conventional cantilever configuration. One comparison produces a reduction of 45% in the fuel consumption while decreasing the minimum takeoff gross weight by 15%. For a second comparison, the fuel weight is reduced by 33% with a decreased minimum takeoff gross weight of 19%. Very attractive vehicle performance can be achieved without the necessity of decreasing cruise Mach number. The results also indicate that a truss-braced wing has a greater potential for improved aerodynamic performance than other innovative aircraft configurations. Further studieswillconsidertheinclusionofmorecomplextrusstopologiesandotherinnovativetechnologiesthatarejudged to be synergistic with truss-braced-wing configurations.

Maneuver Trim Optimization Techniques for Active Aeroelastic Wings

Presented at the 41st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference and Exhibit, Atlanta, GA, April 3-6, 2000.