Mechanical performance of multi-cell thin-walled tubes under static and dynamic axial loading

Abstract

In this paper, the mechanical performance of multi-cell thin-walled tubes with small aspect ratio and diameter thickness ratio and the same weight was studied theoretically, numerically and experimentally. The lightweight devices impact test was designed to get a higher velocity than the drop-weight crashing test or impacting trolley test and the experimental tests were carried out under static and dynamic axial loading. The theoretical mean crushing force (MCF) was obtained according to the simplified super folding element (SSFE) theory, and structural coefficient of the homoeomorphic structure was obtained. Then the numerical models were conducted to investigate the strain hardening on the matrix material. The results showed that the dynamic amplification factor (DAF) for the multi-cell tube to predict the MCF precisely could be ignored at or below the impact velocity 50 m/s. In addition, the experimental results indicated the initial peak forces (IPF) of the tubes were sensitive to the total length of all flanges of the cross-section. The multi-cell partitioning could improve the energy absorption of the thin-walled structures and relieve the increment of the dynamic axial loads. The energy absorption efficiency of multi-cell structure with circular tube is higher than that of multi-cell structure with square tube. The numerical model indicated the dynamic axial impact could lead to the strain hardening of the matrix material. The significant strain hardening could lead to more increment of the force.

Keywords:

• multi-cell thin-walled tube
• structural coefficient
• dynamic amplification factor
• initial peak force
• strain hardening

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work is supported by the National Natural Science Foundation of China (Nos. 12072326 and 52276138), the Science Foundation of the State Key Laboratory of Dynamic Measurement Technology, North University of China (2022-SYSJJ-06), the Support Program for Young Scientific Leaders of North University of China (No. QX202003) and the Fundamental Research Program of Shanxi Province (Nos. 20210302123030 and 202203021212160).