Topological optimization method suitable for metamaterial with function gradient and stretching properties

The invention belongs to the field of metamaterial design relevant technology and discloses a topological optimization method suitable for a metamaterial with a function gradient and stretching properties. The method comprises the steps that (1) a weighting method is adopted to establish a multi-objective optimization model of each layer considering microstructure stretching properties and macrostructure rigidity properties at the same time; (2) the stretching properties and the rigidity properties of the whole structure of the metamaterial in one direction are controlled to be distributed in a gradient form; (3) microscopic displacement and macroscopic displacement in a design domain on each layer and equivalent elasticity properties of a microstructure on each layer are calculated; and (4) an optimization criterion method is adopted to update design variables based on sensitivity obtained through calculation, and then whether an objective function is converged is judged. According to the topological optimization method, the weighting method is adopted to establish the multi-objective optimization model considering the microstructure stretching properties and the macrostructure rigidity properties at the same time, and then optimization is performed, so that the optimized metamaterial has the stretching properties and enough rigidity at the same time.