Response of duplex stainless steel circular hollow sections to lateral low-velocity impact loading

This research investigates the dynamic response of circular hollow section (CHS) tubes of duplex stainless steel (DSS) under lateral impact loading, to simulate accidental impacts in structural engineering applications. Unlike previous studies, which focused on fixed-ended tubes and characterized by a three-hinge failure mechanism and pronounced localized deformation, this investigation focuses on simply supported DSS CHS tubes, which develops a single hinge at mid-span after significant more global deformation. An analysis of the impact sequence of DSS CHS tubes showed that most of the localized indentation and global deformation occurred during the coupling deformation phase, which caused the tubes to absorb most of the impact energy during the coupling and global deformation stages. The fundamental vibrational characteristics and unique mechanical properties of DSS CHS tubes were captured well using a single degree of freedom (SDOF) model. A plot of the initial impact energy parameter (lambda) and the permanent deformation of the tube illustrates the existence of a linear relationship, however, the non-dimensional section size of the DSS CHS (Ds/ts) seems to have a minor impact on the relationship between the permanent deformation pattern and the impact energy. A detailed parametric study was performed to determine the effect of geometric size, kinetic energy, mass, and impact position on the behaviour of DSS CHS tubes subjected to lateral low velocities impacts. These findings offer valuable insights into the performance of DSS CHS tubes and can help in the design and construction of resilient structures.