Light-weight Design Method Of Multi-scale Lattice Structures Based On Topology Optimization

By defining the position of holes and material inside the design domain,topology optimization could achieve the best structure with specific mechanical property through iterate calculation of algorithm.Compared with size optimization and shape optimization,topology optimization has greater freedom when it comes to the design of structure,which makes it able to achieve higher performance in material utilization and structure mechanical property.Multi scale structure optimization is to achieve optimization in both micro scale and macro scale.Compare with traditional way,optimization in multi scale level could further exert the advantages of this method.Compared with the traditional single-scale optimization,the structural optimization performed at multiple scales can further exert the advantages of topology optimization in practical engineering applications.Since multi scale has always been a research hotspot in the field of topology optimization,relevant scholars have proposed various forms of multi-scale optimization methods for this topic.In this paper,we propose a new multi scale structure topology optimization method based on SIMP method(Solid Isotropic Material Penalization).The main research contents are as follows:Firstly,a new way of design unit structure under meso scale level is proposed,and four basic configurations are designed.A feature size parameter is set based on the shape of configurations.With parameter change the meso scale structure is able to simulating carious density units and presents different levels.By using homogenization method,the elastic tensor of unit structure with different size parameters could be calculated.Under the optimization framework of the SIMP method,the density unit is replaced by a pre-designed unit structure,and its elastic tensor is used in the calculation of structural optimization iteration,and then the final structure is subjected to boundary processing as the postprocessing of the optimization method.Then,two examples are been use to verified the validity of this proposed method.The manufacturability and the validity of this method will be proved by compare with the result with the classical SIMP method.Parameters in optimization process also set in different combination to see the impact on structural performance.Based on the results of the example,the simulation of structure was performed using finite element software,and the structural stiffness was detected by continuous application of load.Finally,combined with the additive manufacturing technology,the cantilever beam structure of the two configurations was fabricated,and the loading test was carried out on the construction platform to verify the actual effectiveness of the present proposal.In terms of computational efficiency and structural manufacturability,the multi-scale porous structure topology optimization method proposed in this study has a greater improvement than the classical optimization method.The structure obtained by this method also has a good performance in stiffness.