Energy absorption and shape reformation analysis of low density additively manufactured star-shaped tensegrity structures

Abstract Star-shaped tensegrity structures exhibit unique nonlinear mechanical responses that make them attractive candidates for lightweight energy-absorbing metamaterials. In this study, a super-stable five-pointed star tensegrity-inspired unit (ST5) was designed, additively manufactured using stereolithography, and experimentally evaluated under quasi-static and high strain-rate compressive loading. The proposed architecture replaces traditional tensile cables with compliant, monolithic struts, enabling simplified fabrication while preserving key tensegrity-like behaviors. Compression tests were conducted on double-stacked ST5 units at relative densities of 10%, 15%, and 20% using both quasi-static loading and a modified split Hopkinson pressure bar apparatus. Across all densities, the ST5 units exhibited a distinct nonlinear force–displacement response characterized by extended energy-absorption plateaus and stable rotational deformation. Under dynamic loading, specific energy absorption (SEA) values exceeding 3 J g −1 were achieved, with low-density specimens demonstrating particularly favorable performance and rapid shape recovery following large compressive deformations. The results indicate that the proposed ST5 geometry offers competitive energy-absorption capability compared to previously studied tensegrity-inspired structures, while maintaining excellent post-impact shape reformation. These findings highlight the potential of star-shaped tensegrity-inspired architecture for lightweight impact-mitigation applications across a wide range of strain rates.