Publication Date

2017

Document Type

Thesis

Committee Members

Joy Gockel (Committee Member), Ahsan Mian (Advisor), Raghavan Srinivasan (Committee Member)

Degree Name

Master of Science in Mechanical Engineering (MSME)

Abstract

Three-dimensional (3D) printing, a form of Additive manufacturing (AM), is currently being explored to design materials or structures with required Electro-Mechanical-Physical properties. Microstrip patch antennas with a tunable radio-frequency (RF) response are a great candidate for 3D printing process. Due to the nature of extrusion based layered fabrication; the processed parts are of three-layer construction having inherent heterogeneity that affects structural and functional response. The purpose of this study is to identify the relationship between the anisotropy in dielectric properties of AM fabricated acrylonitrile butadiene styrene (ABS) substrates in the RF domain and resonant frequencies of associated patch antennas and also to identify the response of the antenna before and after a low velocity impact. In this study, ANSYS high frequency structure simulator (HFSS) is utilized to analyze RF response of patch antenna and compared with the experimental work. First, a model with dimensions of 50 mm x 50 mm x 5 mm is designed in Solidworks and three separate sets of samples are fabricated at three different machine preset fill densities using an extrusion based 3D printer LulzBot TAZ 5. The actual solid volume fraction of each set of samples is measured using a 3D X-ray computed tomography microscope. The printed materials appeared to exhibit anisotropy such that the thickness direction dielectric properties are different from the planar properties. The experimental resonant frequency for one fill-density is combined with ANSYS-HFSS simulation results to estimate the bulk dielectric constant of ABS and the equivalent dielectric properties in planar and thickness directions. The bulk dielectric properties are then used in HFSS models for other two fill densities and the simulated results appear to match reasonably well with experimental findings. The similar HFSS modeling scheme was adopted to understand the effect of material heterogeneity on RF response. In addition, a hybrid structure with dimensions of 50 mm x 50 mm x 20 mm is designed with the first 15 mm thickness being a cellular BCC structure and the other 5 mm being a solid cuboid. These samples are printed on an extrusion based 3D printer Stratasys uPrint using ABS. A patch antenna is embedded at the interface of the solid and the cellular structure. Both ABAQUS finite element modeling and experimental methods are used to understand the load-displacement and the energy absorption behavior of the hybrid structure under low velocity impact loadings. The hybrid structure is impacted on both sides to investigate the damage tolerance capabilities of embedded electronic components.

Page Count

144

Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded

2017

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