Impact Resistance of 3D Cellular Structures for Protective Clothing

3D-printed cellular structures have attracted increased attention in recent years due to the many advantages of additive manufacturing technology. However, much of the current research is focused on the use of rigid or combined rigid and soft materials. Herein, the impact resistance of 3D cellular structures manufactured by stereolithography (SLA) additive manufacturing technique using flexible photopolymer resin is investigated. Six different types of cellular structures are designed and manufactured by a photo-polymerizing 3D printer using two different types of flexible photo-curable resin materials. The resistance capacity of these structures against impact force is examined experimentally using a customized free fall "impact drop test", where impact forces transmitted through the impacted structures are captured using a capacitive force sensor underneath the structure, in the form of a real-time impact force versus time plot. The results indicate that the reentrant honeycomb (AU) cellular structure experienced the lowest peak impact force 2.73 and 2.64 N made from Liqcreate and Prusa flexible materials, respectively, and it has the best impact resistance performance among all developed 3D structures.