Anna Gulan
(Advisor: Prof. Mavris)

will defend a master’s thesis entitled,

Conceptual, Trajectory-Based Structural Sizing Method for Hypersonic Glide Vehicles

On

Monday, April 22 at 2 p.m.
Collaborative Visualization Environment (CoVE)

Weber Space and Technology Building (SST II)

and

Microsoft Teams

Abstract

      In recent years, interest in hypersonic vehicles has rapidly developed resulting in an increase in hypersonic research and funding. This push is motivated by the hope that hypersonic vehicles will improve mission performance including velocity, range, and maneuverability. These vehicles are considered highly sensitive to weight though the specific relationship between weight and performance of hypersonic glide vehicles has not been well defined. The first research question will explore this relationship assessing the effects mass on performance parameters including terminal velocity, range, heat load, and mission time. The maximum heat load and terminal velocity were found to be the most sensitive to mass changes and when maneuvers are included in the flight path the total distance becomes increasingly more sensitive to mass.

During the conceptual design phase, engineers rely on weight estimations to ensure the vehicle will meet performance requirements. Current launch weight estimations typically rely on historical regressions. While useful, these regressions are outdated as they do not incorporate hypersonic vehicles and novel technology. This practice results in several gaps as the regressions lack background context reducing opportunities for pinpointing the driving loads and optimization. Additionally, they do not rely on the trajectory or performance parameters of the specific mission requirements. The second research question seeks to address these gaps by introducing a trajectory-based sizing tool to be utilized early in the design process. This tool will produce a more accurate initial weight estimation capable of identifying driving weight parameters. The results showed that for most cases the external pressure was the driving loading condition with the secondary driver being buckling due to bending moment. The peak load typically occurred in the terminal phase during the final dive. Additionally, the sensitivity of structural sizing by aerodynamic parameters was assessed. It was found that the initial height, terminal flight path angle, mission time, and range were the most significant contributors.

When traveling at hypersonic speeds, the load bearing structure will experience high temperatures. These temperatures are caused by both surface heat transfer and skin friction heating. This thermal energy heats the vehicle structure and causes material strength degradation. To reduce this effect a robust thermal protection system (TPS) is needed to shield the structure from the intense thermal energy. The TPS is typically sized to ensure the structural material does not heat beyond its maximum allowable temperature but could be increased in size to reduce the temperature felt by the structure. In attempt to explore the relationship between structural heating and strength degradation, the third research question will explore this relationship and the structural weight reduction that will occur from a reduced operating temperature. The model found that the structural weight increased exponentially with increasing temperature.

Committee

·         Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)

·         Dr. Adam Cox– School of Aerospace Engineering

·         Dr. Kenneth Decker – SpaceWorks Enterprise