Bio-inspired hybrid design and mechanical properties of 3D compression-twist coupling chiral lattice with functional integration

Current lattice structures lack twist characteristics and remain insufficiently studied under large deformations, limiting their potential in advanced engineering, particularly mode conversion. Inspired by the chiral double-helix of DNA, we propose a configuration integrating spatial helical chirality with body-centered cubic (BCC) topology, creating a new class of three-dimensional chiral lattices. This study focuses on the four-helix-chiral hybrid (FHC-BCC) unit cell, examining its large-deformation mechanical response via quasi-static compression experiments and finite element simulations. Specimens were fabricated using selective laser melting (SLM) and tested on a universal testing machine. Parametric analysis shows the hybrid configuration sustains stable twisting, enhances energy absorption, and maintains parallel ligament orientation during deformation. Increasing strut diameter d raises relative density, improves energy dissipation, and enables linear modulation of twist evolution, while increasing layer number N augments densification strain and refines compression-twist coupling for programmable twist control. These results highlight the role of geometric-topological synergy in tuning mechanical performance and broaden the design space for multifunctional metamaterials. The proposed architecture provides a viable route to high-performance, functionally integrated lattice systems with tunable mode conversion capability.