MECHANICAL PROPERTIES OF MULTI-LEVEL GYROID LATTICE STRUCTURES FABRICATED BY SELECTIVE LASER MELTING

Triply periodic minimal surface (TPMS) structures, owing to their outstanding mechanical properties, have shown significant potential in lightweight design for critical aerospace components. To effectively enhance the mechanical performance and lightweight characteristics of TPMS structures, this study proposes an optimization method for multi-level TPMS lattice structures based on stress field guidance. Specifically, a multi-level Gyroid lattice structure is designed and fabricated using selective laser melting (SLM) technology. The performance of the multi-level Gyroid lattice is then compared with that of a primary Ti6Al4V Gyroid lattice structure with the same volume fraction. Through finite element simulations and compression tests, the compression behavior, deformation mechanisms, and energy absorption capabilities of the multi-level Gyroid lattice structure are systematically studied. The results indicate that, compared to the primary Gyroid lattice with the same volume fraction, the multi-level Gyroid structure exhibits significant improvements in compression performance. Specifically, its elastic modulus, yield strength, and ultimate strength are enhanced by approximately 36.52%, 58.55%, and 57.62%, respectively. Moreover, its energy absorption capacity is increased by approximately 42.85%. In terms of failure modes, unlike the primary Gyroid lattice structure, which experiences 45° shear fracture at the center of the inclined compression struts, the multi-level Gyroid lattice initially undergoes layered fracture in the filled regions. Subsequently, a 45° shear fracture occurs in the center of the inclined compression struts in the unfilled regions. The finite element model, based on the Johnson-Cook plasticity and damage models, accurately predicts the deformation behavior and mechanical performance of the multi-level Gyroid lattice structure, with a prediction error within 20%. The multi-level Gyroid lattice structure designed in this study demonstrates superior mechanical properties and energy absorption capabilities, offering new insights and technical support for the design and manufacturing of high-performance lightweight components in aerospace applications. This work presents a novel approach to lattice structure optimization, contributing to the advancement of additive manufacturing techniques and their application in the aerospace industry.