Investigation on Mechanical Properties of Additive Manufactured Hybrid Auxetic Structure
Additive manufacturing (AM) of auxetic structure is gaining prominence for various fields ranging from structural material to biomaterials. This work proposes a novel design of the auxetic structure with regular honeycomb, i.e. hybrid auxetic structure. Additionally, a sharp corner of the auxetic structure is replaced with a fillet feature to stiffen the structure by suppressing the hinging mechanism. All models are fabricated in extrusion-based AM technique using Polylactic acid (PLA) material. A comparison study was carried out on 3D printed samples that were subjected to uniaxial tensile load. To understand the effect on functional and mechanical properties, a tool path strategy with single-pass and zigzag tool paths was proposed. Solid material properties were used in finite element analysis (FEA) to compare with experimental results. Experimental results indicate that hybrid structure takes more load than auxetic structure. The ultimate tensile strength (UTS) of the hybrid structure was 32% more than that of the auxetic structure. The finite element results are in good agreement with the experimental results. The observation reported in this article will help frame design rules and selection of AM processes for applications ranging from structural protection sandwich constructions with low-density cores to tissue engineering and regenerative medicine scaffolds.