Design of a double-helicoidal spacer damping structure inspired by the coelacanth and study of its impact resistance performance

To address the challenge of achieving both high energy dissipation and low structural damage in viscoelastic damping systems for engineering vehicles under complex service conditions, this study introduces a coelacanth-scale-inspired double-helicoidal (DH) Bouligand configuration into the damping system and proposes a novel DH transitional interlayer laminated damping structure. Finite element simulations are conducted to compare the low-velocity impact performance of three configurations: nonhelicoidal (NH), single-helicoidal (SH), and DH. The results indicate that the DH structure with a 15° helicoidal pitch enhances peak load-bearing capacity while suppressing vertical deformation compared with NH and SH designs. Based on simulation findings, DH specimens with various helicoidal angles are fabricated and subjected to single and repeated low-velocity impact tests. In single-impact scenarios, the DH-45 configuration achieves the best balance between load-bearing capacity and deformation resistance, whereas DH-60 configuration exhibits superior energy dissipation. Under multiple impacts, the DH-45 configuration maintains structural integrity, effectively disperses impact energy, and minimizes interlayer damage accumulation, demonstrating the most robust overall impact resistance. This study extends the application of bioinspired helicoidal structures from lightweight aerospace materials to viscoelastic damping systems for engineering vehicles, providing both theoretical foundation and experimental support for the design of damping structures under complex impact conditions.