Fatigue resistance mechanisms and energy absorption capacity of twin-boundary designed sheet-based Gyroid lattice structures built by laser powder bed fusion

Aluminum triply periodic minimal surface (TPMS) lattice structures have numerous potential applications in industrial fields such as automotive, aerospace, and military. To enhance the energy absorption capacity, crack resistance, and fatigue performance of aluminum triply periodic minimal surface (TPMS) lattice structures under compressive and cyclic compressive loads, this study designed three sheet-based Gyroid lattice structures with different orientations by adding twin boundaries. The impact of twin-boundary design on the mechanical properties of the structures was investigated through quasi-static compression tests, finite element simulations, and compression-compression fatigue tests. The results show that while the three lattice structures exhibit similar overall compressive properties, their failure processes differ. The addition of twin boundaries delays structural failure, smooths stress fluctuations during compression, and effectively alters crack propagation direction, enhancing crack resistance. Furthermore, twin boundaries contribute to higher energy absorption capacity by controlling crack propagation. Among the three structures, the double orientation fourfold Gyroid (DFG) lattice structure demonstrates the highest energy absorption efficiency before fracture and excellent fatigue crack resistance. Although the fatigue life of the double orientation fourfold Gyroid (DFG) lattice is relatively short after initial damage, its cracks remain confined to the first layer, allowing it to retain relatively good load-bearing capacity. Post-fatigue analysis reveals that the double orientation fourfold Gyroid (DFG) lattice undergoes less grain fragmentation and deformation compared to the single orientation Gyroid (SG) lattice, highlighting its superior fatigue resistance. These findings provide valuable insights for optimizing the compressive and fatigue performance of lattice structures in engineering applications.