Mechanical Impact Performance of Additively Manufactured Negative Stiffness Honeycombs

Negative stiffness honeycombs materials are comprised of negative stiffness beams arranged in ordered arrays. They are capable of providing isolation from impacts and returning to their initial shape. Previous research by the authors focused on the behavior of negative stiffness honeycombs to quasi-static loading conditions. This paper investigates the behavior of similar negative stiffness honeycombs under impact. The construction of an impact testing rig for the experimental evaluation of negative stiffness honeycombs is discussed. Experimental results from impact tests performed on honeycomb prototypes manufactured using selective laser sintering (SLS) in nylon 11 material are presented and compared with analytical and finite element predictions as well as quasi-static test results.