Date of Award
Master of Science (MS)
Mechanical & Aerospace Engineering
Mechanical and Aerospace Engineering
Among many thermoplastics that are used in engineering, polyamide 6 (nylon 6) is an extremely versatile engineering thermoplastic. Nylon filled with glass fibers has higher mechanical strength and high wear resistance than general purpose nylon. 3D printed composites, based on fused filament modeling, typically suffer from poor bead-to-bead bonding and relatively high void content, limiting their mechanical properties
This thesis explores the effect of compaction pressure and temperature on improving the mechanical properties of 3D printed composites. Engineering moduli in the printing and transverse to printing direction, as well as ultimate strength were measured using the tensile testing with Digital Image Correlation (DIC). Tensile testing is performed on the samples that are compacted at different temperatures with pressure. In addition, microscopic studies were carried out to evaluate the void content for different compaction pressures and temperatures. Fiber orientation state was measured for different sets of samples. Differential scanning calorimetry (DSC) was carried out to calculate the degree of crystallinity and possible changes in crystalline morphology as a result of annealing temperature profile.
The results indicate that by selecting appropriate heat treatment profiles both strength and modulus of 3D printed composites can be significantly improved. Strength was improved by over 50% and 100% in printing and transverse directions respectively, and twofold increase of the modulus in printing direction was found. In this respect, the observed mechanical behavior will be explained in terms of various parameters such as degree of compaction, crystalline structure, orientation state and void content.
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Ajith Kumar Jain, Pushpashree J..
"The Effect of Compaction Temperature and Pressure on Mechanical Properties of 3D Printed Short Glass Fiber Composites"
(2020). Master of Science (MS), Thesis, Mechanical & Aerospace Engineering, Old Dominion University, DOI: 10.25777/fghz-m472