Purpose <p>Honeycomb structures are widely applied in architecture, aerospace, and biomedical engineering due to their lightweight yet high-strength characteristics. This study investigates a novel star-shaped honeycomb structure (SITH), formed by replacing the inclined edges of conventional star-shaped honeycombs (SSH) with isosceles triangular elements. The research focuses on the multiple plateau stress responses of the SITH under dynamic impact loading from different in-plane directions, as well as the effect of wall-thickness gradient strategies on improving energy absorption performance.</p> Methods <p>Finite element models were validated against quasi-static compression experiments to ensure accuracy. Subsequently, the deformation patterns and crushing behaviors of SITH were analyzed under low-, medium-, and high-speed loading conditions. To enhance energy absorption, three wall-thickness configurations-uniform, positive gradient, and negative gradient-were compared.</p> Results <p>Under low-speed loading, the SITH exhibited three plateau stresses along the Y-axis and two along the X-axis. Compared with SSH, the specific energy absorption (SEA) of SITH-Y and SITH-X increased by 46.15% and 50.96%, respectively. Across all loading speeds, the SITH demonstrated superior mechanical properties and energy absorption capacity. Furthermore, gradient wall-thickness designs in the Y-axis direction, whether positive or negative, further improved energy absorption efficiency.</p> Conclusion <p>This study highlights the unique multi-plateau stress behavior and enhanced energy absorption capability of the SITH. It also confirms that wall-thickness gradient designs provide an effective approach to further improving performance, offering new insights for the development of high-performance lightweight energy-absorbing structures.</p>