Mechanical Engineering Seminars - Effect of thermal protection system on vibration of aerospace structural panels
Master’s thesis Defense
Department of Mechanical Engineering
University of Maine, Orono, ME 04469
At the end of Space Shuttle mission, it re-enters the earth’s atmosphere with a speed that exceeds 17000 mph, slowing down to land speed causes friction that results in external surface high temperatures, as high as 3000 °F which is above the melting point of steel. While in Orbit, the orbiter airframe and major systems are exposed to external temperature fluctuations between the day and night phase from -200 °F to +200 °F during each 90-minute orbit. Therefore, to protect the Orbiter, its occupants, its airframe and major systems from the temperature extremes, special thermal shields were invented known as the Thermal Protection System (TPS) to withstand stresses and vibrations that are experienced during launch as well as thermally induced stresses imposed during temperature changes. Adding these thermal tiles to the structure, changes its material properties as they are an addition to the mass; subsequently the modes change causing the structure to vibrate differently and consequently its response behaviour will differ upon impact.
This study is intended to further develop methodologies that can accurately measure, monitor and predict the condition of the Thermal Protection System (TPS) of primary and secondary structural components of the Space Shuttle. Also, investigate the structural and non-structural systems as the non-structural mass can affect the evaluation of vibration structure. The research is performed using a combination of experimental methods that consist of physical impact tests, analytical methods, monitoring techniques and data analysis techniques.