Failure mechanism of expanded metal tubes under axial crushing

The failure mechanism of expanded metal tubes under axial crushing is addressed herein. Experimental results have shown that when collapsing the tubes, the expanded metal cells closes until the plastic moment in all nodes along the mid-section of the tubes is attained exhibiting a plastic collapse mechanism. From this deformed configuration, a simple analytical expression is developed for the ultimate strength of the tube based on a rigid-plastic analysis of a frame-like structure. In addition, the energy absorption capacity of the tubes is also calculated. Theoretical predictions for both strength and energy are in good agreement with experimental results taken from the literature. Thereafter, a numerical study was conducted in order to investigate the validity of the theoretical model depending on the expanded metal cell geometry. It is found that the load-displacement response and failure mechanism of the tubes depend upon the aspect ratio of the expanded metal cell.