BS in Aerospace Engineering
Aerospace Engineering Department
This project was completed at the California Polytechnic State University, San Luis Obispo Aerospace Engineering Structures and Composites Lab during Spring Quarter 2013. The purpose of this project was to research and to gain insight into the effects of fabrication methods and of modifying cure cycles for Newport NB-301 12l 2x2 Twill Weave Carbon Fiber material properties. The two fabrication methods used were autoclave and heat press (compression molding) methods. Each fabrication method used two cure cycles, a recommended cure cycle of 275°F for 1 hour and a modified cure cycle of 250°F for 1.5 hours. The exact product data sheet of the composite used could not be found, this project attempted to generate an estimate for the missing material properties. To find tensile properties and flexural properties for each sample, testing was completed for the different cure methods. Material properties were found using the same standard of testing used by Newport Adhesives and Composites for their published data. The tensile standard used by Newport was ASTM D-638 Type 1, however due to the complexity of manufacturing the samples a simpler standard was found (ASTM D-3039). The flexure standard using for this project and by Newport was ASTM D-790. After testing seven tensile samples and eight flexure samples for each of the four different configurations, it was concluded that for plate fabrication the compression molding method of the heat press resulted in the best material properties (highest modulus and highest ultimate strength. The best mechanical properties for tensile testing resulted from the recommended 275°F cure cycle. The tensile mechanical properties that resulted from samples cured with the heat press at 275°F had an average tensile strength of 85.5 ksi (590 Mpa) and an average tensile modulus of 7.08 Msi (48.8 GPa).Unfortunately the flexure testing was not effective in displaying a clear trend for the best cure cycle. Thus no conclusion could be drawn to determine the best curing cycle for flexure.