Design and crashworthiness behaviors of novel 3D printed cutting-type energy-absorbing composite structures

To simultaneously meet crashworthiness and lightweight requirements, a novel 3D-printed cutting-type energy-absorbing structure, fabricated using short carbon fiber-reinforced polyamide, was proposed. The printed structure, comprising a central cylinder and round bulges, absorbed energy through the extrusion and shearing of the bulges as the cylinder moved through the base under applied stress. The impact of key geometrical parameters on the crashworthiness behaviors of the structure, including the thickness and outer diameter of the round bulge, as well as the spacing between the round bulges, was investigated under quasi-static cutting tests. The parametric study revealed that increasing the round bulge thickness within the permissible range significantly improved the crashworthiness of the structure. Specifically, specimens with higher round bulge thickness exhibited a remarkable 238.8% increase in specific energy absorption compared to specimens with lower round bulge thickness. Additionally, the crushing force efficiency of the printed structure initially increased and then decreased as the round bulge thickness increased, with the highest value reaching 68.56%. Furthermore, appropriately increasing the round bulge diameter and decreasing the spacing between the round bulges could improve the crashworthiness of the structure. The maximum specific energy absorption of the printed structure in this study was 25.14 J/g. Compared with most metal cutting-type energy-absorbing structures reported in the literature, the proposed structure in this study showed great potential as energy absorbers used in different areas for passive safety system design.