Mimicking Hardwoods Using Honeycombs Manufactured from Acrylonitrile Butadiene Styrene (ABS): A Comparison of Mechanical Properties

Wood has been used as a material to build mechanical structures for thousands of years. As a natural composite of cellulose fibers embedded in a matrix of lignin, this organic, cellular solid resists both tension and compression. Its properties depend on the direction of loading of its cells − whether radially, tangentially, or axially − and such anisotropy is modeled well as a regular honeycomb structure. With the development of rapid prototyping technologies using materials that resist rot, it is advantageous to investigate the ability of a 3D printed honeycomb to model the mechanical properties of wood. Open-cell, hexagonal honeycomb structures with densities spaning those of hardwoods were fabricated using acrylonitrile butadiene styrene. The mechanical properties of the honeycombs were compared to those reported for each of the woods to ultimately assess the quality of the mimicking. Specimens for each relative density were printed and compressed by loading along the out-of-plane axis (axial) as well as the in-plane axis (transverse). While the printed honeycombs proved to be less stiff than the reported values for wood, the trends in the relative densities agree with the models. This study is novel, as it uses a 3D printer to mimic the wood structure and thus develops important insight into mimicking the natural material with a thermoplastic. Additionally, this work explores the use honeycomb models at high relative densities similar to wood.