Study on the mechanisms of topological structure and microscopic defects on the fatigue performance of additive manufacturing lattice structures

Abstract Three-dimension (3D) lattice structure design incorporates topological configurations, while additive manufacturing (AM) process introduces defects. They will affect the fatigue damage of lattice structures together. In this paper, the fatigue damage behavior of lattice structures with internal defects is simulated based on the extended finite element method (XFEM), focusing on analyzing the combined influence mechanisms of defects and topological structures on their fatigue performance. The influence of defect quantity and location on the fatigue performance of lattice structures is analyzed. The fatigue damage behaviors of Simple cubic (SC) and body-centered cube (BCC) structures are simulated. The simulation results indicate a clear layer by layer fatigue failure mode. Under high cyclic stress loading, the topologies play a major role in the fatigue life of lattice structures, and microscopic defects play a major role in fatigue properties under low cyclic stress. Different topologies have different sensitivities to defects. Currently, studies on simulating the fatigue behavior of 3D lattice structures based on XFEM are limited. The research findings can clarify the combined influence mechanism of topological structures and micro-defects on the fatigue performance of AM lattice structures, providing theoretical support for the topological design of AM lattice structures in aluminum alloys.