AbstractsEngineering

The purpose of this project was to investigate the viability and practicality of using a desktop 3D printer to fabricate small UAV airframes. To that end, ASTM based bending and tensile tests were conducted to assess the effects of print orientation, infill density, infill pattern, and infill orientation on the structural properties of 3D printed components. A Vernier Structures & Materials Tester was used to record force and displacement data from which stress-strain diagrams, yielding strength, maximum strength, and the moduli of elasticity were found. Results indicated that print orientation and infill density had the greatest impact on strength. In bending, vertically printed test pieces showed the greatest strength, with yield strengths 1.6 � 10.4% higher than conventionally extruded ABS�s 64.0MPa average flexural strength. In contrast, the horizontally printed specimens showed yield strengths reduced anywhere from 17.0 � 34.9%. The tensile test specimens also exhibited reduced strength relative to ABS�s average tensile yield strength of 40.7MPa. Test pieces with 20% infill density saw strength reductions anywhere from 47.8 � 55.6%, and those with 50% saw strength reductions from 33.6 � 47.8%. Only a single test piece with 100%, 45� crisscross infill achieved tensile performance on par with that of conventionally fabricated ABS. Its yield strength was 43MPa, a positive strength difference of 5.5%.As a supplement to the tensile and bending tests, a prototype printable airplane, the Phoebe, was designed. Its development process in turn provided the opportunity to develop techniques for printing various aircraft components such as fuselage sections, airfoils, and live-in hinges. Initial results seem promising, with the prototype�s first production run requiring 19 hours of print time and an additional 4 � 5 hours of assembly time. The maiden flight test demonstrated that the design was stable and controllable in sustained flight. Advisors/Committee Members: Jacob, Jamey (advisor), Kidd, James (committee member), Conner, Joseph (committee member).