Experimental and numerical performance assessment of square aluminum and steel energy absorbers with circular hole discontinuities

This work reports the performance of energy absorbers made in mild-steel and aluminum thin-walled square tubes under quasi-static compression tests. They have circular holes discontinuities laterally drilled on two or four opposing faces of the tube, according to three different distances based on the effective crushing distance, resulting in 23, 36, and 46 mm, as well as two diameters 8 and 12 mm. The tubes are 300 mm in effective length, 50 mm wide, and thickness varies. A substantial variation at performance parameters occurs with wall thickness and material changes. Failure initiators with 12 mm in diameter distant from each other 23 and 36 mm lead to better performance for aluminum and steel absorbers, respectively. Von Mises equivalent stress reaffirms that failure initiator influences stress distribution; consequently, the deformation process and; eigenvalue buckling analysis highlights the relation of buckling effect with the peak force and the stiffness of the tube face.