Energy absorption assessment of bio-mimicked hybrid Al/PP sandwich tube: Experimental and Numerical Investigation

This paper aims to investigate quasi-static and low-velocity impact responses of three manufactured bio-inspired hybrid multi-cell aluminum and polypropylene (Al/PP) sandwich tubes experimentally and numer-ically. The configurations are inspired by biological structures such as the horsetail, human tendons, and spongy bone. The crushing characteristics and axial collapse of sandwich tubes are discussed and compared with the quasi-static axial behavior of single Al and PP tubes. Further investigations, based on the accuracy of simulation results of the tested specimens, using the commercial nonlinear LS-DYNA software, on the effects of inner tubes diameter and material permutation are perceived through the full-factorial approach of FE parametric study. The results revealed that, packing the Al and PP tubes as hierarchical tubes generally improves the crushing patterns of individual hollow tubes. Also, specimens with aluminum and polypropylene cores have the highest amount of specific energy absorption under quasi-static and low-velocity impact loading, respectively. Finally, considering the interaction effects between the sandwich tube components, it can be seen that sandwiching single hollow tubes generally improves important crashworthiness indicators like peak crush force, crush force efficiency, energy absorption, and specific energy absorption when compared to the sum of these parameters in single hollow tubes.