Date of Award
Master of Science in Mechanical Engineering (MSME)
Abdel-Hamid Ismail Mourad
Fibre-reinforced polymeric composites used for aerospace applications are subjected to different environmental conditions during their operational life, such as moisture and temperature, which can adversely affect their performance over time. On the other hand, the standard fabrication process of these composite aircraft components requires a certain level of in-process vacuum compaction during the composite lay-up process to ensure the escape of entrapped air between the composite layers to prevent the formation of voids, through the application of bleeders/breathers around the composite laminate known for creating a channel for air to escape through. The aim of this study is to evaluate the effect of moisture and temperature on the integrity of plain weave is woven carbon/epoxy laminated composites for both compacted and non-compacted groups, where the compacted group included the application of both in-process compactions during the composite lay-up process and the use of bleeders/breathers around the laminate, while the non-compacted group did not. Twelve-ply specimens were fabricated and immersed in water heating chambers maintained at different immersion temperatures of 40°C, 70°C and 95°C for a period that varied from one to 10 months. Mechanical, physical, and thermal properties were experimentally investigated, and the effects of temperature, moisture, and immersion time on the deterioration of the composite material were studied against both compacted and non-compacted groups. Results revealed that moisture and temperature have a deteriorative impact on the performance of the composite, and it was observed that high temperatures accelerate the degradation mechanism in the composite. An insignificant difference was observed in the thermomechanical properties between compacted and non-compacted specimens at the immersion temperatures of 40°C and 70°C, but slight degradation was observed at the immersion temperature of 95°C, which indicates that in-process compaction and application of bleeders/breathers for twelve-ply monolithic laminates may be required at high-temperature applications.
Al Kuwaiti, Maryam Hamad Helal Thabet, "IMPACT OF DIFFERENT ENVIRONMENTAL CONDITIONS ON THE THERMO-MECHANICAL CHARACTERISTICS OF COMPACTED AND NON-COMPACTED CARBON/EPOXY PLAIN WEAVE WOVEN LAMINATED COMPOSITES" (2020). Theses. 896.