Experimental investigation on energy absorption capability of 3D printed onyx nested rings under lateral loading

This study presents a focused experimental exploration into the energy absorption characteristics and failure mechanisms of nested circular rings under lateral loading. The rings were 3D printed using the fuse deposition modeling method with an onyx material containing chopped carbon fiber. The dimensions of the rings were determined to be the same in width and thickness, while the diameter had four different values. The samples of nested rings consist of at least two and up to five individual rings. These samples were obtained by using individual rings in various different sequences and orders. Two different configurations for each nested sample type were also studied to observe the effect of the ring sequences and orders on the energy absorption capability. It is concluded from the results that even though the single ring with the smallest diameter has the highest force values, the highest energy absorption and specific energy absorption values were obtained in another single ring. The alignment of the single rings has a superior effect on the energy absorption capacity of the nested samples. Also, a gain in absorbed energy was observed in nested samples due to the interaction between the single rings. This interaction showed that the algebraic summation of the energy values of single rings used in a nested sample was lower than the energy value of the same nested sample. In the nested samples, the absorbed energy increased proportionally to the number of single rings. However, the crashworthiness parameters were affected quite differently from the energy absorption capacity. While the highest energy absorption values are obtained in nested samples with five single rings, other nested samples reached the highest values in terms of some of the crashworthiness parameters. The NR5-A sample absorbed 52% and 88% higher energy compared to the same combination of nested samples, which contain four and three single rings, respectively. Additionally, the specific energy absorption value of this sample is 32% and 47% higher than the same nested samples mentioned above. Considering these results, it can be expressed that the NR5-A sample is the best design in terms of an ideal energy absorption structure.