A star-shaped tubular structure with multiple-directional auxetic effect.

• The star-shaped tubular structures of STL structures were designed, manufactured and studied. • The proposed structures exhibited two distinct deformation modes. • The STL structure has a better auxetic behavior with different materials under quasi-static uniaxial compression. • The auxetic effect of STL structures were investigated under different load direction. A majority of tubular structures have been widely studied due to their superior mechanical performance. Existing works on star-shaped tubular structures have focused on improving their stability and energy absorption performance. This paper proposes a novel star-shaped tubular lattice structure (STL), which not only possesses excellent mechanical properties but also exhibits exceptional auxetic effect. In addition, such structures exhibited two distinct deformation modes under different loading directions. Numerical and experimental studies of the mechanical behavior of the star-shaped tubular structure demonstrated low peak stresses under lateral loading and superior bearing capacity and stability under axial compression. Most importantly, the structure embodied a significant auxetic effect under the direction of both loads. The mechanical performance of the star-shaped tubular structures was investigated by changing wall thickness and angles, which can realize the optimal design. This study enriches the research on star-shaped tubular structures and provides a new perspective and reference for the design of auxetic tubular metamaterials in the future. Furthermore, the star-shaped tubular structure with auxetic behavior has considerable potential for applications in civil engineering and protective fields. [Display omitted] [ABSTRACT FROM AUTHOR]