Miriam Dennis, Graduate Student, University of Florida
Amanda Schrand PhD, Principle Investigator, Air Force Research Laboratory
The incorporation of 3D printed structures into systems is progressing at an unprecedented rate due to the ease of prototype iteration for complex designs at relatively low cost. In this presentation, we tested the ability of periodic 3D printed gyroid structures, which consist of an infinitely connected, non-linear surface, to mitigate mechanically-induced shock. The complex gyroid crystal structure was readily printed in acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS) and polyvinyl alcohol (PVA) on a Makerbot Replicator 2X, then tested on a Split Hopkinson Pressure Bar (SHPB). We explored alterations to the classic SHPB setup for testing the low impedance, 3D printed cellular samples to most accurately reflect the stress state inside the sample at strain rates ranging from 700 to 1750 s-1. The sample dimensions were optimized to diameter of 0.86” by height of 0.4” and stress-strain curves generated. It was discovered that the gyroid can effectively absorb energy (as the strain increases) without introducing additional stress. The result is that the gyroid structure absorbs the impact of the test by crushing the structure. Additional tailoring of the unit cell dimensions, material composition and dimension will yield improved strength and samples that can achieve higher strain rates.