Chad Alexander

(Advisor: Prof. Dimitri Mavris)

will defend a master’s thesis entitled,

A Multi-fidelity Approach to Mass Estimation of Hypersonic Glide Vehicles

On

Monday, April 14th at 3:15 pm.

In Weber SST III, CoDE

and

Teams meeting link

Abstract 

Hypersonic vehicles, which operate at speeds exceeding Mach 5, present significant design challenges for the defense and aerospace sectors. In particular, hypersonic glide vehicles (HGVs) are emerging as critical national security assets due to their high speed, long range, and increased survivability. However, as hypersonic technology advances, traditional empirical-based studies become less reliable, potentially leading to ineffective decision-making and failed development programs. To mitigate these risks, there is a growing need for adaptive, physics-based technology assessment methodologies that enhance analysis accuracy and support the maturation of advanced technologies. 

Due to the critical importance of accurate knowledge of vehicle mass properties, one area of interest focuses on leveraging a physics-based adaptive method to efficiently obtain accurate mass estimations at early design phases. This method would utilize different mass estimation techniques to efficiently and accurately provide mass properties of novel concepts and would improve the transition between empirical, analytical, and computational techniques. While such an approach would increase the chance of a successful development program broadly, the sensitive nature of hypersonic technology limits the availability of open data, hindering research collaboration across institutions. Therefore, there is an additional need for an approach that accounts for large design uncertainties while providing essential information to support hypersonic technology development. 

This thesis investigates a multi-fidelity approach to mass estimation for HGVs, combining historical mass estimating relationships with physics-based methods to improve confidence in early-stage analysis. A key objective is to determine when empirical mass estimating relationships—commonly used in conceptual design—should be supplemented or replaced by physics-based analytical methods. Given the scarcity of historical data, empirical relationships from analogous vehicle classes were analyzed and calibrated using open-source benchmarks, leading to the development of refined regression models for estimating glider mass. Low-fidelity models were also employed to reduce design space dimensionality and guide refinement toward higher-fidelity analyses. 

Higher-fidelity mass estimation methods were explored to complement empirical approaches and assess the trade-offs between fidelity and computational effort. Notional hypersonic glider structures were sized using multiple beam theories under relevant flight loads, evaluating the suitability of beam analysis for early-phase mass estimation. The accuracy of different beam theories in capturing structural behavior was examined, and mass estimates were compared across fidelity levels by sizing a generic hypersonic waverider at both low and high fidelities. 

The multi-fidelity approach considered in this research is designed to improve multidisciplinary design optimization (MDO) environments, enhancing mass prediction accuracy, decision-making confidence, and overall design efficiency. Additionally, this research explores a structured methodology 

for transitioning between mass estimation techniques, enabling more informed decision-making in early hypersonic glider design programs. By offering an adaptable mass estimation process, this research supports the iterative development of advanced hypersonic gliders, improving both the precision and speed of design iterations in defense and aerospace applications. 

By exploring a multi-fidelity mass estimation approach, this research enhances predictive capabilities necessary for early-stage hypersonic vehicle design. Improving the transition between empirical, analytical, and computational techniques ensures a more adaptable and reliable mass estimation approach, mitigating the risks associated with traditional methodologies and large design uncertainties. As hypersonic technology continues to evolve, the insights from this study provide a foundation for improved decision-making, reduced analysis inaccuracies, and more efficient design processes. Ultimately, this work contributes to the broader goal of accelerating hypersonic vehicle development, strengthening national security, and fostering innovation for high-speed aircraft. 

Committee 

• Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)
• Prof. Claudio Vinicius Di Leo– School of Aerospace Engineering
• Dr. Evan Harrison – Aerospace Systems Design Lab
• Dr. Adam Cox – Aerospace Systems Design Lab