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Ph.D. Thesis Proposal
by
Grant A. Rossman
(Advisor: Prof. Robert D. Braun)
CONCEPTUAL THERMAL MODELING, TESTING, AND DESIGN OF FLEXIBLE THERMAL PROTECTION SYSTEMS
3:00 PM, Monday, November 23rd, 2015
Montgomery Knight Building
Room 317
ABSTRACT:
Flexible Thermal Protection Systems (FTPS) have been investigated to support many applications, including thermal protection of inflatable atmospheric entry vehicles. This flexible blanket is composed of a stack of material sheets, including heat rate resistant outer fabrics, heat load resistant insulation, and an air-tight gas barrier to prevent pressure leaks. This dissertation advances thermal modeling, material property testing, and design of FTPS.
In this investigation, a 1-D thermal response model is used to predict in-depth temperatures of FTPS layups during arc-jet ground testing. An extended inverse estimation methodology is developed and applied to the thermal model, utilizing concepts from inverse heat transfer analysis, parameter estimation, and probabilistic analysis. Thermal response model input parameters are adjusted to minimize error between temperature predictions and measurements.
Some FTPS insulators experience decomposition under extreme heating conditions, while others do not. To further characterize fibrous insulators that undergo decomposition, a thermogravimetric analysis (TGA) test campaign was performed to obtain the associated activation energy for thermal response modeling. A new material testing methodology was developed to obtain the approximated distribution of activation energy from a set of repeated TGA experiments. Using this methodology, the mean, uncertainty, and distribution of activation energy for multiple fibrous insulators is estimated.
A simulation-based FTPS screening and design methodology is developed to obtain a final FTPS insulator configuration efficiently. The screening and design process uses inputs such as a candidate insulator pool, insulator material properties, and a nominal mission profile. Using the methods mentioned above, candidate insulators are screened and designed efficiently, providing FTPS insulator stackup configurations that satisfy mission requirements.
Committee members:
Dr. Robert Braun (Chair)
Dr. Marcus Holzinger
Dr. Brian German
Dr. John Dec
Dr. Mairead Stackpoole
