Experimental Study of Energy Absorption of Square Column under Multi-Indentation Loading

This research deals with experimental investigation on energy absorption and deformation of thin walled square columns under multi-indentation loading. The main goal of this research is to examine the effect of number and diameter of indenters and distance between them on the energy absorption parameters. First, square aluminum specimens with specific lengths were prepared and also an adjustable fixture for applying multi-indentation loading was fabricated. Then the indentation loading were applied on the specimens during a quasi-static condition with a constant loading rate. During loadings, the specimens were located between an almost rigid platen and the adjustable indenters. The load-displacement diagrams of specimens were obtained and the energy absorption parameters were calculated. The results indicate that the amount of absorbed energy in multi-indentation process increases significantly respect to single-indentation. By increasing the distance between indenters in multi-indentation loading, the load- displacement diagram shifts upward and moves toward the twice of single-indentation diagram. Also, by increment of diameter of indenters and distance between them, the amount of absorbed energy increases 20-60% due to formation of bigger plastic hinges.