3D printing is a revolutionary manufacturing method that allows the productions of engineering parts almost directly from modeling software on a computer. With 3D printing technology, future manufacturing could become vastly efficient. However, it is observed that the procedures used in 3D printing differ substantially among the printers and from those used in conventional manufacturing. In this thesis, the mechanical properties of engineering products fabricated by 3D printing were comprehensively evaluated and then compared with those made by conventional manufacturing. Three open-source 3D printers, i.e., the Flash Forge Dreamer, the Tevo Tornado, and the Prusa, were used to fabricate the identical parts out of the same material (acrylonitrile butadiene styrene). The parts were printed at various positions on the printer platforms and then tested in bending. Results indicate that there exist substantial differences in mechanical responses among the parts by different 3D printers. Specimens from the Prusa printer exhibit the best elastic properties while specimens from the Flash Forge printer exhibit the greatest post-yield responses. There further exist noticeable variations in mechanical properties among the parts that were fabricated by the same printer. Depending on the positions that the parts were placed on a printer platform, the properties of resultant parts can vary greatly. For comparison, identical parts were fabricated using a conventional manufacturing method, i.e., compression molding. Results show that compression molded parts exhibit more robust and more homogeneous properties than those from 3D printing. During 3D printing, the machine code (e.g., the Gcode) would provide the processing instructions (the x, y, and z coordinates and the linear movements) to the printer head to construct the physical parts. Often times the default processing instructions used by commercial 3D printers may not yield the optimal mechanical properties of the parts. In the second part of this thesis, the orientation-dependent properties of 3D printed parts were examined. The multi-layered composite theory was used to design the directions of printing so that the properties of 3D printed objects can be optimized. Such method can potentially be used to design and optimize the 3D printing of complex engineering products. In the last part of this thesis, the printing process of an actual automobile A-pillar structure was designed and optimized. The finite element software (ANSYS) was used to design and optimize the filament orientations of the A-pillar. Actual parts from the proposed designs were fabricated using 3D printer and then tested. Consistent results have been observed between computational designs and experimental testing. It is recommended that the filament orientations in 3D-printing be “designed” or “tailored” by using laminate composite theory. The method would allow 3D printers to produce parts with optimal microstructure and mechanical properties to better satisfy the specific needs.

Indiana University-Purdue University Indianapolis (IUPUI) / Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands in porous structure forms. MOFs have been proposed in use for gas adsorption, purification, and separation applications. This work combines MOFs with 3D printing technologies, in which 3D printed plastics serve as a mechanical structural support for MOFs powder, in order to realize a component design for gas adsorption. The objective of the thesis is to understand the gas adsorption behavior of MIL-101 (Cr) MOF coated on 3D printed PETG, a glycol modified version of polyethylene terephthalate, through a combined experimental and modeling study. The specific goals are: (1) synthesis of MIL-101 (Cr) MOFs; (2) nitrogen gas adsorption measurements and microstructure and phase characterization of the MOFs; (3) design and 3D printing of porous PETG substrate structures; (4) deposition of MOFs coating on the PETG substrates; and (5) Monte Carlo (MC) modeling of sorption isotherms of nitrogen and carbon dioxide in the MOFs. The results show that pure MIL-101 (Cr) MOFs were successfully synthesized, as confirmed by the scanning electron microscopy (SEM) images and X-ray diffraction (XRD), which are consistent with literature data. The Brunauer-Emmett-Teller (BET) surface area measurement shows that the MOFs samples have a high cover- age of nitrogen. The specific surface area of a typical MIL-101 (Cr) MOFs sample is 2716.83 m2/g. MIL-101 (Cr) also shows good uptake at low pressures in experimental tests for nitrogen adsorption. For the PETG substrate, disk-shape plastic samples with a controlled pore morphology were designed and fabricated using the fused deposition modeling (FDM) process. MOFs were coated on the PETG substrates using a layer-by-layer (LbL) assembly approach, up to 30 layers. The MOFs coating layer thicknesses increase with the number of deposition layers. The computational model illustrates that the MOFs show increased outputs in adsorption of nitrogen as pressure increases, similar to the trend observed in the adsorption experiment. The model also shows promising results for carbon dioxide uptake at low pressures, and hence the developed MOFs based components would serve as a viable candidate in gas adsorption applications.

Implementation of a comprehensive set of forms that visualizes the physical existence originally immaterial artifacts.

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In this study, we quantified the Chemistry-Process-Structure-Property (CPSP) relations of a Ti-6Al-4V/TiB functionally graded material to assess its ability to withstand large deformations in a high throughput manner. The functionally graded Ti-6Al-4V/TiB alloy was created by using a Laser Engineered Net Shaping (LENS) process. A complex thermal history arose during the LENS process and thus induced a multiscale hierarchy of structures that in turn affected the mechanical properties. Here, we quantified the functionally graded chemical composition; functionally graded TiB particle size, number density, nearest neighbor distance, and particle fraction; grain size gradient; porosity gradient. In concert with these multiscale structures, we quantified the associated functionally graded elastic moduli and overall stress-strain behavior of eight materials with differing amounts of titanium, vanadium, aluminum, and boron with just one experiment under compression using digital image correlation techniques. We then corroborated our experimental stress behavior with independent hardening experiments. This paper joins not only the Process-Structure-Property (PSP) relations, but couples the different chemistries in an efficient manner to effectively create the CPSP relationships for analyzing titanium, aluminum, vanadium, and boron together. Since this methodology admits the CPSP coupling, the development of new alloys can be solved by using an inverse method. Finally, this experimental data now lays down the gauntlet for modeling the sequential CPSP relationships.

This project aims to build up a soft robotic gripper that mimics human hands and design a closedloop control system. A soft gripper model is established with Finite Element Method (FEM) to describe the relation between air pressure input and gripper deformation. The best soft gripper dimensions are selected according to the FEM model and the gripper is then fabricated with Fused Deposition Modeling (FDM) 3D printing method. Closed-loop angle control before the soft gripper touches the object is used to ensure a precise grasp. A camera sensor is used for the acquisition of the bending angle and a pressure regulator is applied to supply the air pressure. A closed-loop experiment platform is built based on a proportional-integral (PI) controller to realize the precise deformation control of the soft gripper. Finally, the grasp of some soft or brittle objects using the soft gripper is performed as a demonstration. / Projektet syftar till att bygga upp en mjuk robotgripare som efterliknar mänskliga händer och utformar ett slutet styrsystem. Mjuk griparmodell är upprättad med Finite element Method (FEM) för att beskriva förhållandet mellan lufttrycksingång och gripar deformation. De bästa mjuka gripdimensionerna väljs enligt FEM-modellen och griparen tillverkas sedan med Fused Deposition Modeling (FDM) 3D-tryckningsmetod. Vinkelstyrning med sluten slinga innan den mjuka griparen berör objektet används för att säkerställa ett exakt grepp. En kamerasensor används för att erhålla böjningsvinkeln och en tryckregulator appliceras för att tillföra lufttrycket. En experimentplattform med sluten slinga är byggd baserad på en proportionellintegrerad (PI) styrenhet för att realisera den exakta deformationskontrollen för den mjuka griparen. Slutligen utförs grepp om vissa mjuka eller spröda föremål som använder den mjuka griparen som en demonstration.

In this thesis, I have explored the possibilities of what furniture can look like on a moon base. How they will be made and what resources to use. What will the living conditions be like and why producing on a faraway place is important for future interstellar missions. By combining art and design, I will present a realistic concept that fits the need of the astronauts stationed on the moon and know what one might need when on a moon station.

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