Auxetic tubes to internal loading: Experiments and analytical modelling

Abstract

A tube is a common structural component for energy absorption and structural protection against loads, such as pressure vessels in engineering. Auxetic design may improve the performance of tubes in this regard. Little research has been conducted on the responses of auxetic tubes to internal loading. Therefore, this work aims to systematically investigate the deformation behaviour and energy absorption performance of auxetic tubes under quasi-static internal pressure. The typical auxetic pattern, re-entrant, was employed for tubes. Re-entrant tube samples were printed, and quasi-static experiments were conducted. A novel loading apparatus was designed to transform axial compression into internal load. Based on the deformation of auxetic tubes and the plastic hinge mechanism, an analytical model was developed for re-entrant tubes in expansion. Finite element simulations were also carried out for validation and comparison. Additionally, the effects of wall material properties, cell numbers, and cell patterns were discussed.