Energy Performance of Non-Conventional Metal Tubular Systems via a New Multiaxial

This experimental study investigates the effect of a new loading path characterized by a new multiaxial alternation path, on the mechanical behaviour of metallic tubular structures. These are simple thin-walled tubes, recognized as one of the best energy absorption systems (EAS) in their class. Equipped with the same cylindrical cross-section geometry, the specimens used are of two metals, copper and aluminium, subjected to multiaxial alternating plastic buckling. For this purpose, a new specific experimental device (ACTP-S) has been developed. It is a new variant of our patented biaxial device (ACTP, [1]). The introduction of an alternative compression-torsion stress is designed to further promote the phenomenon of over-hardening during plastic flow. So, in addition to the classical uniaxial crushing entitled Bi0° as reference, three biaxial configurations BiS45, BiS53 and BiS60 governed by ACTP-S helicoids with their respective angles of inclination, are listed. Several plastic buckling tests were carried out under quasistatic (5 mm/min) and dynamic (9 m/s) regimes. Among other significant results, the study reveals an unquestionable improvement in energy absorption for multiaxial configurations, a gain of 84 % compared to the reference case in favor of BiS60, configuration of extreme complexity, justifying a change in the behavior of the materials.