Anisotropic butterfly-inspired lattice structures for enhanced impact resistance

• A butterfly-inspired anisotropic lattice structure is developed to improve impact resistance and energy absorption. • Structural anisotropy enables controlled deformation and efficient stress redistribution under compressive loading. • The design–performance relationship is elucidated through combined theoretical analysis and numerical simulation. Lattice structures have attracted wide attention due to their lightweight and energy-absorbing characteristics, yet their practical application remains constrained by localized failure induced by stress concentration, leading to a drastic decline in impact resistance. Inspired by the uniform stress distribution in butterfly wings, we introduce a novel anisotropic lattice design based on a butterfly-inspired body-centered cubic (BCCB) topology. By incorporating a critical transition from catastrophic I-shaped single shear in BCC to stable X-shaped conjugate shear bands in BCCB, this structure effectively mitigates stress concentration and enhances both strength and impact tolerance, while the BCCB structure (0.62 relative density) offers a lightweight advantage. The experimental and numerical simulations were employed to investigate the static and dynamic mechanical behavior of the lattice structures. and Digital Image Correlation (DIC) was used to analyze the stress distribution in lattice structures. The results in this work exhibits a specific energy absorption of 7.2 J/g (6 times that of the traditional BCC) and an elastic modulus of 31.33 MPa (2.5 times higher). Theoretical and numerical analyses elucidate the anisotropic mechanical behavior and yield behavior, offering fundamental insights into the structure–function relationship. This design holds promise for advanced deployment in aerospace, automotive, and protective systems where lightweight impact-resilient materials are critical.