Experimental and numerical investigation on bending collapse of embedded multi-cell tubes

Traditional multi-cell tubes exhibit much higher energy absorption capacity and efficiency than single-cell tubes when subjected to axial or transverse loads. This work investigates the bending resistance of a type of composite multi-cell tubes, which is easily obtained by embedding a group of small single tubes into an enveloping tube. This type of embedded multi-cell tubes is flexible in sectional dimensions and shape, easily prepared and highly cost-effective. Three-point bending tests are first performed to investigate the bending behavior and response of embedded multi-cell tubes with different cell configurations. The influences of friction condition, end treatment and partially filling are also studied experimentally. Numerical simulation of the experiment is then carried out by employing the explicit finite element code LS-DYNA. The simulation results generally compare well with experiment. The quasi-static and dynamic bending responses of both embedded and traditional multi-cell tubes with almost the same sectional shape and dimensions are investigated numerically. The bending resistance of embedded multi-cell tubes is found to account for about 65-72% of corresponding traditional multi-cell tubes.