Bi-Surface Induction in Biomimetic Multi-Gradient Foam-Filled Tubes With Enhanced Energy Absorption: Theory, Experiment, and Simulation

The axial compressive deformed configurations of traditional and lightweight energy absorption thin-walled tubes are uncontrollable, while the introduction of internal and external induction grooves can control the deformed configuration at predetermined intervals to improve the stability of axial collapse. Thus, by introducing induction grooves and the concept of gradient into the design of energy-absorbing structures, an efficient energy absorber consisting of a biomimetic foam-filled diameter-gradient tube with internal and external gradient induction grooves (FD-GIG tube) is proposed. The axial compressive experiments of the FD-GIG tubes filled with density uniform foam are carried out, and the deformation-related failure modes are clearly observed. An analytical model for the axial crushing behavior of an FD-GIG tube filled with density gradient foam is established. The axial crushing behavior of FD-GIG tube filled with density gradient foam is studied analytically and numerically. The analytical average force–displacement curves of FD-GIG tubes filled with density gradient/uniform foam match well with experimental and numerical results. Increasing cone angle, density gradient factor, induction groove height factor, and induction groove depth factor can all effectively increase the specific energy absorption of the FD-GIG tube up to 81.8% maximum.