The effect of radial distance of concentric thin-walled tubes on their energy absorption capability under axial dynamic and quasi-static loading

Highlighs
• For the first group, the highest energy absorption occurs in dimensionless distance of 1.
• For the second group, the highest energy absorption occurs in dimensionless distance of 0.66.
• Energy absorption of two-concentric tubes system is more than single-tube system.

This study investigates the effect of radial distance of concentric thin-walled tubes on their energy absorption capability through simulation by LS-Dyna finite element software and experimental tests. Concentric cylindrical tubes made of aluminum 1050 with different radii were exposed to axial dynamic and quasi-static loading and optimum radial distance in maximum energy absorption condition was obtained. In overall, 24 states for simulation and 8 states for experimental tests have been investigated. Dynamic loading has been applied in form of hitting of a 75 kg mass with speed of 8 m/s and quasi-static loading of the structures has been done with speed of 150 mm/min and elongated to 70% of the initial length of tubes. Comparison of results of the two concentric tubes and single-tube system with equal mass of structures showed that energy absorption of two-tube system is more than single-tube system. Furthermore, in concentric tubes׳ system, in the state where the distance of both tubes has changed, the energy absorption is more than the state where the radius of the outer tube is constant and just the radius of the inner tube changes.