Evaluating the NPR effect of computer-aided 3D auxetic structure

Primary author: Zihui Zhao
Faculty sponsor: Hang Liu

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman


Most materials exhibit positive Poisson’s ratios, which means they become narrower in the transverse direction and longer in the direction of stretching under tension. Materials fabricated with auxetic structures have negative Poisson’s ratios (NPRs) which behave contrarily to conventional materials. Auxetic structures have a number of enhanced properties, such as increased shear modulus, indentation resistance, fracture toughness, and energy absorption among others. This research studied utilizing 3D printing technique to create 3D auxetic structures with elastomers. Various spatial configurations of the 3D structure, printing parameters, and elastomer composition were investigated for their influence on the properties of printed auxetic structures, including energy absorption, auxetic ratio, and compression stress/strain. Experimental results showed that overall these developed 3D auxetic structures were able to present sufficient NPR effect under compressive loading. The various parameters studied all affected the auxetic ratio, energy absorption, and compression stress and strain. The resultant 3D structures have great potential for various applications, including protective gears for sports (e.g., helmet and knee padding).