Ph.D. Defense

Bogdan-Paul Dorca

(Advisor: Prof. Dimitri Mavris)

Monday, April 14
09:45 a.m. EST

Collaborative Visual Environment (CoVE)

Weber Space Science and Technology Building (SST II)

and

Online: Click here to join the meeting

Abstract
Time has an ever-increasing value in today’s society, as an economist might express the value of time in opportunity costs. This is especially relevant in the aviation sector where current civil aircraft fly at Mach 0.80-0.85, while supersonic aircraft can cruise at more than twice that Mach number and thus offer the potential of a dramatic decrease in travel time. This could cause a global transportation paradigm shift, as a supersonic aircraft cruising around Mach 1.8 would mean that you can get anywhere around the world, from New York, in less than 10 hours. 

As speeds exceed Mach 1, several challenges emerge. Transonic flight introduces complex modeling difficulties, the aerodynamic center shifts, sonic booms become a concern, and aerodynamic heating intensifies. Additionally, supersonic aircraft often exhibit poor subsonic performance, leading to inefficiencies during takeoff, landing, and lower-speed flight segments. Overcoming these obstacles is essential for realizing the full potential of supersonic air travel.

A promising technology that could pave the way for the future generations of supersonic aircraft is morphing. A morphing aircraft can be defined as a vehicle that changes its configuration to increase its performance at different flight conditions, respectively it can continuously modify its geometry in order to enhance flight performance, control authority and multi-mission capability. Together with the recent technological developments of smart materials, the unconventional transformation of morphing provides adaptability for multiple flight phases when compared to conventional airplanes that are typically optimized with a bias towards a single mission segment (e.g. cruise for transport aircraft). This feature is especially beneficial for supersonic aircraft who must fly subsonically over land as supersonic flight is currently banned in that region by regulatory agencies. 

The objective of this research is to investigate the usefulness and applicability of morphing concepts for supersonic aircraft by developing a novel methodology focused on introducing this technology as early as possible in the design cycle. Most current research focuses on applying morphing technology onto existing aircraft which have been already designed as fixed-wing aircraft. This retrospective approach limits the potential benefits of morphing, as many design decisions would likely differ if the technology were considered from the outset.

A hybrid design methodology that incorporates the benefits of forward design and inverse design through the use of Invertible Neural Networks (INN) is proposed to deal with the design challenges of morphing technology. With the addition of multiple morphing degrees of freedom as control variables in a trajectory optimization design approach, the trade-off between subsonic and supersonic cruise efficiency will be less severe and off-design performance will be enhanced due to the flexibility that morphing technology provides. Aircraft can be optimized for all flight segments simultaneously which can lead to significant weight and cost savings as well as an increase in the total number of flyable off-design routes. The main result of the methodology is the morphing schedule, which defines the time-continuous evolution of the morphing aircraft configuration throughout the mission trajectory and thereby allows designers to know exactly how the aircraft must optimally fly each individual route. Surrogate modeling can also be employed to ensure that performance impacts can be captured at a reduced computational time compared to using specialized tools. All in all, this approach would thus enable rapid design space exploration for SSTs equipped with morphing technology.

Committee

• Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)
• Prof. Lakhsmi N. Sankar – School of Aerospace Engineering
• Prof. Daniel P. Schrage – School of Aerospace Engineering
• Dr. Jimmy C. M. Tai – School of Aerospace Engineering
• Dr. Sriram Rallabhandi – National Aeronautics and Space Administration (NASA)
• Mr. Jonathan Seidel – National Aeronautics and Space Administration (NASA)