Maher Amer (Committee Member), Ahsan Mian (Advisor), Raghavan Srinivasan (Committee Member)
Master of Science in Mechanical Engineering (MSME)
This research focuses on the energy absorption capability of additively manufactured or 3D printed polymer lattice structures of different configurations. The Body Centered Cubic (BCC) lattice structure is currently being investigated by researchers for energy absorption applications. For this thesis, the BCC structure is modified by adding vertical bars in different arrangements to create three additional configurations. Four designs or sets of the lattice structure are selected for comparison including BCC, BCC with vertical bars added to all nodes (BCCV), BCC with vertical bars added to alternate nodes (BCCA), and BCC with gradient arrangements of vertical bars (BCCG). Both experimental and finite element modeling approaches are used to understand the load-displacement as well as energy absorption behavior of all four configurations under both quasi- static compression and low-velocity impact loadings. Once designed in SolidWorks, all four sets of samples were prepared using Acrylonitrile Butadiene Styrene (ABS) polymer material on a Stratasys uPrint 3D printer. The Instron universal testing machine was used for the quasi-static loading test whereas an in-house built ASTM Standard D7136 drop tester was used to capture the impact response. For impact samples, sandwich panels were fabricated using the 3D printed ABS lattice core structures. In this case, four Kevlar face sheets were attached to the lattice core structure using a two-part epoxy adhesive. The absorbed energy was found by integrating the area under the load-displacement curve for both compression and impact tests. To interpret the results, Specific Energy Absorption (SEA) that is the absorbed energy over the mass, should be considered. Moreover, the investigation of the SEA was also performed using Finite Element Analysis (FEA) for comparison. ANSYS Workbench was used to predict the behavior of the lattice structures under compression load. However, Abaqus Dynamic Explicit was used to capture the low-velocity impact response of sandwich panels with printed lattice cores. It is observed from both experimental and FEA data that selective placement of vertical support struts in the unit-cell influences the absorption energy of the lattice structures. In the compression test, the highest SEA was captured for the BCCV specimen which has more weight when compared with the others. However, the highest SEA was captured in impact test for the BCCA specimen.
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
Copyright 2017, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.