Abstract: Facing the demand of additive manufacturing high-strength porous structure, the topology optimization design method was used to optimize the structure of the regular hexahedron by adjusting the porosity and the position of the load, so as to obtain three topology porous structures of point topology optimization, line topology optimization and face topology optimization. AlSi10Mg porous structure samples were fabricated by selective laser melting (SLM). The mechanical properties of three kinds of porous structures were analyzed by compression test, and the failure mechanism of porous structures were analyzed by finite element method. The results show that the yield strength and elastic modulus of point topology optimization, line topology optimization and face topology optimization porous structure decrease with the increase of porosity. According to the finite element analysis, it can be seen that the stress distribution of the face topology optimization porous structure is the most uniform. Under the same displacement, the mechanical performance of the topology optimization porous structure is the best, the line topology optimization structure is the second, and the point topology optimization structure is the worst. The results show that the face topology optimization is the best of the three optimization methods. The mathematical relationship between mechanical properties and geometric parameters were established by using the classical Gibson-Ashby model, which can be used to predict the relationship between porosity and mechanical properties of the three kinds of structures, which provides a theoretical basis for the application of porous structures.

Key words: selective laser melting, topology optimization, porous structure, mechanical properties, finite element method