Compressive strength and energy absorption characteristics of the negative stiffness honeycomb cell structure

Abstract

Combining the performance advantages of chopped carbon fiber-reinforced nylon composites (MarkForged Onyx) with the manufacturing advantages of 3D printing, the negative stiffness honeycomb cell structure (NSH-C) was fabricated using fused filament fabrication technology. The study examined how to build directions, fill patterns, and wall layers, affecting the compressive strength and energy absorption characteristics of NSH-C. The results show that the printing parameters of Flat direction, triangular fill pattern, and two wall layers are optimal for NSH-C, which makes NSH-C exhibit a strong negative stiffness phenomenon with energy absorption efficiency up to 70% and peak force of approximately 185 N. In addition, the effect of structural parameters on the compressive strength and energy absorption characteristics of the structure was numerically simulated. Simulation results suggest that appropriately increasing the initial apex height of the curved beam, increasing the in-plane thickness of the curved beam and reducing the span of the curved beam will all be expected to further improve the mechanical performance of NSH-C.