Research On Optimization Design Method Of Space Node Topology Based On Additive Manufacturing

With the wide application of large-span space structures and the continuous pursuit of novel structures by engineers,the styles of space nodes are constantly innovating.The perfect combination of force and shape will be the highest state of space structure form in art.The topology optimization method aims to find the optimal distribution position of structural materials under a certain target.In the design,it is often possible to design a structure with a peculiar shape that meets the target requirements.It can be applied to the design of spatial structure nodes to a certain extent.Liberate the designer’s imagination and design a spatial structure with rich shapes.At the same time,the continuous breakthrough of the current additive manufacturing technology also makes it possible to manufacture complex nodes after topology optimization.The application of additive manufacturing and topology optimization in space nodes needs continuous exploration.In addition to the application research of optimization methods,it is also necessary to consider the performance of products manufactured by additive manufacturing technology.Whether the node can be manufactured after the optimized design and whether the performance of manufacturing and design are consistent are all issues that need to be solved urgently.To this end,this paper explores algorithm programming,finite element solution,and additive manufacturing collaborative topology optimization-manufacturing integration method for space nodes.The problem of material anisotropy in the printing direction of the current additive manufacturing technology is studied,and the optimization method considering the constraints of self-supporting manufacturing is studied to provide a set of efficient and feasible innovative solutions for the form-finding of spatial structure nodes.The main research contents and conclusions are as follows:(1)Based on the bidirectional incremental optimization method(BESO),a full-process method of spatial node optimization-additive manufacturing is explored.Compared with the optimization results of the variable density method that comes with the commercial finite element software,the maximum stress and maximum deformation of the space node model under the shear force condition optimized by the software integrated method can be reduced by 9.8% and 23.2%.The maximum stress of the model can be reduced by 21.1%,the maximum deformation can be reduced by 33.6%,and the performance is significantly improved.(2)In this paper,based on the engineering elastic constant,the effect of material anisotropy on the structure is studied.It is found that there are differences in the mechanical properties of the additive manufacturing specimens in all directions.The maximum and minimum elastic moduli in different directions differ by 24.1%;obvious anisotropy.Substitute the anisotropic properties into the optimization solution.The calculation shows that the anisotropic properties of the material will change the shape of the optimization results.There is an optimization result with the maximum stiffness,and the maximum and minimum stiffness of different results differ by 15.1%.(3)A self-supporting method for structures is studied by characterizing the 0-1 explicit bones of the structure,combined with a triangular boundary filter and a triangular pyramid boundary filter so that the added support can be preserved in iterations.In this paper,the space node calculation example is optimized and applied.The optimization results obtained after the support algorithm calculation show that the maximum deformation does not exceed4.1%;the maximum volume change does not exceed 3.1%.The performance sacrifice is less,and the optimization results can basically achieve the self-supporting effect,which performs well in the molding test.