Revealing anisotropic fatigue behavior and multiscale failure mechanisms of bio-inspired heterogeneous glass sponge lattice structures fabricated by laser powder bed fusion under high-cycle compression fatigue

Abstract

Lattice structures (LSs) fabricated via additive manufacturing (AM) are widely used for their lightweight, high strength-to-weight ratio, and energy absorption properties. However, the long-term fatigue performance of metallic lattice structures (MLSs) remains challenging, primarily due to structural failure and manufacturing defects. This study investigates the dynamic compressive fatigue behavior of bio-inspired glass sponge lattice structures (GSLSs) and their variants. Combining micro-CT characterization reveals a structure–property relationship where nodal geometry optimization improves fabrication quality and fatigue performance. Results show that GSLS achieves the highest fatigue strength (0.7 $F_{\max }$ = 17.897 kN) at 10⁴ cycles, while GSLS-I exhibits the highest fatigue strength ($N_f$) at 10⁶ cycles (0.7 $F_{\max }$ = 11.827 kN). Meanwhile, failure mode analysis shows that stress concentrations at nodes and horizontal overhangs accelerate crack initiation, explaining the more excellent fatigue stability of GSLS, GSLS-II, and GSLS-S (R² = 0.99, 0.95, and 0.96) compared to GSLS-I and GSLS-III (R² = 0.69 and 0.76). Finite element analysis (FEA) further elucidates fatigue failure mechanisms, confirming cyclic ratcheting and strut-level stress distribution as key factors influencing fracture. This study provides a predictive framework for fatigue failure in MLSs and offers insights into optimizing high-performance LSs for aerospace, automotive, biomedical implants, and other engineering applications.