Ph.D. Defense

Anusha Harish

(Advisor: Prof. Dimitri Mavris) 

"Methodology for Aircraft Architecture Selection & Design Optimization" 

On 

Friday, April 7 

11:00 a.m. EDT
https://gatech.zoom.us/j/97780752185?pwd=WGNFYkVtK3NhdFFGcm1kcnpTQ3c2Zz09

Abstract
Growing concerns about the environment have led to aviation agencies around the world such as IATA, ICAO, NASA, and ACARE to set targets to curb noise, emissions, and fuel consumption in the coming years. In order to achieve these goals, several new aircraft technologies and concepts in the areas of unconventional airframe configurations (such as blended wing body and truss-braced wing), advanced propulsion systems (example, open rotor engines and electrified propulsion), alternative energy sources (such as hydrogen, battery, etc.) as well as propulsion-airframe integration concepts (distributed propulsion, boundary layer ingestion, etc.) have been proposed. There are over 100,000 possible combinations of these technologies. However, this vast architecture space has not yet been fully explored. Therefore,  there is a need for a lower-order analysis methodology capable of rapidly analyzing different combinations.  

This research aims to propose a methodology for rapid generation and assessment of architectures in order to identify promising ones that are capable of meeting future environmental goals. There are 3 key aspects to this problem - generation of alternatives, evaluation of the design space for the architectures, and finally the optimization of the aircraft designs. The first research area focuses on the generation of architecture alternatives using Constraint Programming for every aircraft configuration with known propulsive-airframe integration concept, given the compatibility between different components. Since there is currently no methodology that automatically generates architecture alternatives, this proposed methodology is validated by comparing its results against known or studied architectures in the literature.   

The second research area is aimed at developing a ”pre-conceptual” design methodology that can quickly evaluate and optimize architecture alternatives with fewer design details and consistent set of assumptions and requirements. Parameters such that the energy and the power split between different components, and the path for power flow from the energy source to the thrust producing device at both sizing points as well as throughout the mission segments are proposed and used in the determination of key performance indicators such as global chain efficiency, energy specific air range and thrust specific power consumption.  

The objective of the final research question is the optimization of the aircraft design for each generated architecture. A multi-objective optimization algorithm is implemented to optimize each design with aircraft weight and energy consumption as the two objectives, while meeting all aircraft requirements such as range, payload, cruise altitude and speed, mission power requirements, etc.  

Thus, a complete, generalized, universal architecture enumeration and pre-conceptual design and optimization methodology is proposed. The capability of this methodology is demonstrated in the final use case where architectures with different alternatives in terms of energy sources – jet fuel, batteries (high specific power, high specific energy) and hydrogen; and advanced propulsion system architectures with distributed propulsion – electrified propulsion and hydrogen propulsion hybrids, are generated, evaluated, and optimized for a 2050 Entry-into-Service. Furthermore, the impact of technologies on the aircraft performance is investigated through a technology sensitivity study. 

Committee 

• Prof. Dimitri Mavris – School of Aerospace Engineering (Advisor) 
• Prof. Daniel Schrage – School of Aerospace Engineering 
• Prof. Graeme Kennedy – School of Aerospace Engineering 
• Dr. Jonathan Gladin – School of Aerospace Engineering 
• Dr. Eric Hendricks – NASA Glenn Research Center