Matching Items (21)
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- All Subjects: Additive Manufacturing
- Creators: Mechanical and Aerospace Engineering Program
- Creators: Chemical Engineering Program
Description
Active pixel sensors hold a lot of promise for space applications in star tracking because of their effectiveness against radiation, small size, and on-chip processing. The research focus is on documenting and validating ground test equipment for these types of sensors. Through demonstrating the utility of a commercial sensor, the research will be able to work on ensuring the accuracy of ground tests. This contribution allows for future research on improving active pixel sensor performance.
ContributorsDotson, Breydan Lane (Author) / White, Daniel (Thesis director) / Jansen, Rolf (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This paper summarizes the [1] ideas behind, [2] needs, [3] development, and [4] testing of 3D-printed sensor-stents known as Stentzors. This sensor was successfully developed entirely from scratch, tested, and was found to have an output of 3.2*10-6 volts per RMS pressure in pascals. This paper also recommends further work to render the Stentzor deployable in live subjects, including [1] further design optimization, [2] electrical isolation, [3] wireless data transmission, and [4] testing for aneurysm prevention.
ContributorsMeidinger, Aaron Michael (Author) / LaBelle, Jeffrey (Thesis director) / Frakes, David (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
The aerospace industry has been conducting research on the additive manufacturing (AM) process since the 1980's, but companies have recently just begun to apply AM in hopes that this new technology will meet or exceed the requirements met by previous manufacturing methods, as well as producing more cost effective, geometrically-complex products. This investigation evaluated the performance of 3D-printed aerospace test specimens made by Powder Bed Fusion Technologies, and compared them to forged specimens. A design of experiments varying build parameters was conducted in order to determine AM component porosity. Factors such as powder post-processing, directionality of the build, and fractology of the samples were evaluated through tensile strength testing and hardness testing of Inconel 718 wrought and EBM printed materials. Using electron microsopy, the responses to these factors were analyzed for stress fractures, grain boundaries, and other defects that occurred in the testing process. The comparison determined which metallurgical process provides the most effective material for aircraft usage.
ContributorsNez, Brittany Amber (Author) / Parsey, John (Thesis director) / Hsu, Keng (Committee member) / Godfrey, Donald (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Automobiles can advance greatly with the introduction of metal additive manufactured components. Additive tooling is slowly becoming additive manufacturing and someday the technology will be advanced enough that high volume can be supported. This research was conducted in order to show the advantages metal additive manufacturing has in the automobile industry. One large advantage to metal additive manufacturing is mass reduction. Components can be designed for production with different geometries than other manufacturing methods. The change in geometry can significantly reduce the product volume and therefore mass. Overall, mass reduction in the automotive industry is beneficial. Mass reduction can increase performance and fuel economy of the car. Once metal additive manufacturing becomes capable of higher production, metal additive manufacturing will play a major role in automobile manufacturing. Research was conducted to design and produce an optimized AC compressor bracket. The bracket was designed to the specifications of the OEM component, and the mass was reduced by more than half.
ContributorsSawyer, Brenton James (Author) / Hsu, Keng (Thesis director) / Parsey, John (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This study aims to provide a foundation for future work on photo-responsive polymer composite materials to be utilized in additive manufacturing processes. The curing rate of 2,2-dimethoxy-2-phenyl-acetophenone (DMPA) in thin (<20 µm) and thick (>2 mm) layers of DMPA and poly(ethylene glycol) diacrylate (PEG-DA) mixtures was assessed for 5.0 w/v% (grams per 100 mL) concentrations of DMPA dissolved in PEG-DA. The polymerization rate and quality of curing was found to decrease as the concentration of DMPA increased beyond 1.0 w/v%; thus, confirming the existence of an optimum photo-initiator concentration for a specific sheet thickness. The optimum photo-initiator concentration for a 3-3.1 mm thick sheet of PEG-DA microstructure was determined to be between 0.3 and 0.38 w/v% DMPA. The addition of 1,6-hexanediol or 1,3-butanediol to the optimum photo-initiator concentrated solution of DMPA and PEG-DA was found to increase the Tg of the samples; however, the samples could not fully cure within 40-50 s, which suggested a decrease in polymerization rate. Lastly, the DMPA photo-initiator does not produce gaseous byproducts and is translucent when fully cured, which makes it attractive for infusion with strengthening materials because quality light penetration is paramount to quick polymerization rates. It is recommended that more trials be conducted to evaluate the mechanical properties of the optimum curing rate for DMPA and PEG-DA microstructures as well as a mechanical property comparison following the addition of either of the two alcohols.
ContributorsPiper, Tyler Irvin (Author) / Green, Green (Thesis director) / Lind, Mary Laura (Committee member) / School of Sustainability (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
This research addresses the need for improvement in radiation sensors for applications of ionizing radiation such as radiotherapy. The current sensors involved are polymer gel dosimeters, MOSFETs, radio-chromic films, etc. Most of the sensors involved require expensive equipment's and processing facilities for readout. There is still a need to develop better sensors that can be clinically applied. There are numerous groups around the world trying to conceive a better dosimeter. One of the radiation sensors that was developed recently was based on fluorescence signal emitted from the sensor. To advance the field of radiation sensors, a visual indicator has been developed in-lab as a method of detect ionizing radiation. The intensity of change in color is directly dependent on the amount of incident ionizing radiation. An aqueous gold nanoparticle sensor can be used to accurately determine the incident amount of ionizing radiation1. A gold nanoparticle sensor has been developed in lab with the use of hexadecyltrimethylammonium bromide (C16TAB) as the templating molecule. In the presence of ionizing radiation, the colorless gold salt is reduced and templated, creating a dispersion within the fluid1. The formation of suspended nanoparticles leads to a color change that can be visually detected and accurately analyzed through the employment of a spectrometer. Unfortunately, the toxicity of C16TAB is high. It is expected the toxicity can be reduced by replacing C16TAB with an amino acid, as amino acids can act as templating molecules in the solution and many are naturally occuring2. The experiments included a screening of 20 natural amino acids and 12 unnatural amino acids with the gold salt solution in the presence of ionizing radiation. Stability and absorbance testing was conducted on the amino acid sensors. Additional screening of lead amino acid sensors at various concentrations of irradiation was conducted.
ContributorsGupta, Saumya (Co-author) / Rege, Kaushal (Co-author, Thesis director) / Pushpavanam, Karthik (Co-author, Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This study analyzes mechanical properties of additively manufactured plastic materials produced in a conventional 3D printer. This topic has generally been studied in controlled scenarios, and this study aims to reflect the properties seen by consumers. Layered prints are inherently anisotropic due to the direction of the layers and associated weaknesses or stress concentrators. Thus, the ultimate strength and elastic modulus of plastic specimens produced using default settings are compared based on print orientation angle, and trends are observed. When a specimen is parallel to the build plate, it tends to have ultimate strength and elastic modulus near the published bulk values of 13.2MPa and 404-710MPa, but these values tend to decrease as the print angle increases.
ContributorsGarry, Allan Edward (Author) / Patel, Jay (Thesis director) / Mertz, Benjamin (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The removal of support material from metal 3D printed objects is a laborious necessity for the post-processing of powder bed fusion printing (PBF). Supports are typically mechanically removed by machining techniques. Sacrificial supports are necessary in PBF printing to relieve thermal stresses and support overhanging parts often resulting in the inclusion of supports in regions of the part that are not easily accessed by mechanical removal methods. Recent innovations in PBF support removal include dissolvable metal supports through an electrochemical etching process. Dissolvable PBF supports have the potential to significantly reduce the costs and time associated with traditional support removal. However, the speed and effectiveness of this approach is inhibited by numerous factors such as support geometry and metal powder entrapment within supports. To fully realize this innovative approach, it is necessary to model and understand the design parameters necessary to optimize support structures applicable to an electrochemical etching process. The objective of this study was to evaluate the impact of block additive manufacturing support parameters on key process outcomes of the dissolution of 316 stainless steel support structures. The parameters investigated included hatch spacing and perforation, and the outcomes of interests included time required for completion, surface roughness, and effectiveness of the etching process. Electrical current was also evaluated as an indicator of process completion. Analysis of the electrical current throughout the etching process showed that the dissolution is diffusion limited to varying degrees, and is dependent on support structure parameters. Activation and passivation behavior was observed during current leveling, and appeared to be more pronounced in non-perforated samples with less dense hatch spacing. The correlation between electrical current and completion of the etching process was unclear, as the support structures became mechanically removable well before the current leveled. The etching process was shown to improve surface finish on unsupported surfaces, but support was shown to negatively impact surface finish. Tighter hatch spacing was shown to correlate to larger variation in surface finish, due to ridges left behind by the support structures. In future studies, it is recommended current be more closely correlated to process completion and more roughness data be collected to identify a trend between hatch spacing and surface roughness.
ContributorsAbranovic, Brandon (Author) / Hildreth, Owen (Thesis director) / Torres, Cesar (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Polymer modified tuning fork-based sensors were fabricated to assure reproducibility. The effect of system valve switching on the modified tuning fork-based sensors was studied at the different temperature. The response to Xylene gas sample on stabilized modified tuning fork-based sensors with temperature was defined while learning about the key analytical performance for chemical sensors to be used in the real-world application.
ContributorsRohit, Riddhi S (Author) / Forzani, Erica (Thesis director) / Tsow, Francis (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
A method has been developed that employs both procedural and optimization algorithms to adaptively slice CAD models for large-scale additive manufacturing (AM) applications. AM, the process of joining material layer by layer to create parts based on 3D model data, has been shown to be an effective method for quickly producing parts of a high geometric complexity in small quantities. 3D printing, a popular and successful implementation of this method, is well-suited to creating small-scale parts that require a fine layer resolution. However, it starts to become impractical for large-scale objects due to build volume and print speed limitations. The proposed layered manufacturing technique builds up models from layers of much thicker sheets of material that can be cut on three-axis CNC machines and assembled manually. Adaptive slicing techniques were utilized to vary layer thickness based on surface complexity to minimize both the cost and error of the layered model. This was realized as a multi-objective optimization problem where the number of layers used represented the cost and the geometric difference between the sliced model and the CAD model defined the error. This problem was approached with two different methods, one of which was a procedural process of placing layers from a set of discrete thicknesses based on the Boolean Exclusive OR (XOR) area difference between adjacent layers. The other method implemented an optimization solver to calculate the precise thickness of each layer to minimize the overall volumetric XOR difference between the sliced and original models. Both methods produced results that help validate the efficiency and practicality of the proposed layered manufacturing technique over existing AM technologies for large-scale applications.
ContributorsStobinske, Paul Anthony (Author) / Ren, Yi (Thesis director) / Bucholz, Leonard (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05