Finite Element Modeling of the Axial Crushing of AA6061 T4 and T6 and AA6063 T5 Structural Square Tubes with Circular Discontinuities

This research focused on the energy absorption capabilities of axially loaded structures fabricated from aluminum alloy extruded tubing with a square cross section. Quasi-static compressive testing was used to examine the effects of dual centrally-located circular hole discontinuities on the energy absorption characteristics of the extrusion test specimens. In addition to previously characterized progressive buckling and global bending modes, collapse modes involving cracking and splitting were observed in several experimental tests. For this reason, finite element models of each test specimen were developed using a material model incorporating damage mechanics. The suitability of using shell elements versus solid elements to model these relatively thick walled structures was investigated. A good correlation was observed between the results of the experimental quasi-static compressive tests and the results of the finite element simulations conducted using LS-DYNA.