| The growing maturity of selective laser melting（SLM）technology has effectively promoted the development and application of lattice lattice structures in aerospace,energy storage and medical implants.In this paper,the mechanical properties of BCC lattice lattice structure prepared by SLM are studied,and the elastic parameters in the theoretical calculation and test of BBC lattice structure are compared.The failure mode and internal stress state distribution of the sample are studied by simulation,and all the results are applied to the lightweight structure optimization design of vehicle connectors.The research content of this paper is mainly divided into the following aspects:Firstly,two kinds of theoretical prediction formulas of cell structure are proposed.By comparing and optimizing the cell structure design method,the difference rate between the theoretical prediction and the relative density of the model is reduced by 15%-20%.On the basis of homogenization,the structural flexibility matrix,equivalent Young’s modulus,equivalent shear modulus and Poisson’s ratio of lattice lattice lattice are calculated and analyzed.Three modeling methods of solid models are proposed,namely,the element space equivalent filling method,the element structure array method and the topology optimization simulation data filling method.Compared with the element space equivalent filling method,the element structure array method can effectively reduce the number of triangular patches that affect the forming accuracy and the number of simulation mesh.The number of triangular patches of models with different aspect ratios is reduced by 87.49%,88.84%,89.52%,90.06%and 90.36%,respectively,The accuracy of sample preparation and the efficiency of simulation are improved.Secondly,316L stainless steel lattice lattice lattice samples with relative densities of 15%,20%,25%,30%and 35%were prepared by SLM technology,and the matrix material properties required for theoretical calculation and simulation were obtained.The quasi-static compression tests were carried out,and the theoretical elastic modulus and experimental elastic modulus were compared.The difference rates of elastic modulus of samples with different aspect ratios were 18.7%,13.8%,8.6%,5.3%and 4.1%,respectively,The difference between the theoretical elastic modulus and the experimental elastic modulus of the sample is gradually close.The load form and deformation trend of the sample in the compression process are analyzed.The finite element analysis of the solid model was completed,and the fitting of the simulation was verified by comparing with the test results.Combined with the compression process and the simulated stress nephogram,the special stress distribution changes in the samples with different length diameter ratios were found.By comparing the compression process of the samples in the test,it was found that the whole structure had the characteristics of"drum shape".With the increase of the length diameter ratio,the load distributed by the rod diameter was larger and larger compared with the node,The internal stress increases gradually.The equivalent stress distribution range of the lattice structure with the aspect ratio of 0.181 is 200-400mpa,the equivalent stress distribution range of the lattice structure with the aspect ratio of 0.212 is 300-450mpa,the equivalent stress distribution range of the lattice structure with the aspect ratio of0.240 is 350-500mpa,and the equivalent stress distribution range of the lattice structure with the aspect ratio of 0.266 is 400-550mpa,The equivalent stress distribution range of the rod diameter of the lattice structure with the aspect ratio of 0.291 is 450-600mpa.For the overall structure,the load capacity of the lattice structure with different aspect ratios is stronger and stronger with the increase of the size,and the load stress of the rod diameter in the stress nephogram is larger and larger,and the load distributed to the rod diameter is larger and larger with the increase of the aspect ratio.Finally,all the results are applied to the optimization design of lattice lattice lattice structure.The finite element analysis of vehicle connecting parts is carried out,and a complete lightweight scheme is formulated.The lightweight design of parts is carried out by using BCC lattice lattice lattice topology optimization simulation data filling method.The scheme is formulated based on the"five step"structure optimization idea proposed in this paper,and the structural optimization goal of 38.79%of the optimization area is achieved,The whole structure can realize the optimization based on the internal stress distribution of parts under load,that is,the material distribution can realize the reasonable distribution based on the change of regional stress distribution.The structural performance parameters are analyzed by finite element simulation,and the maximum equivalent stress,equivalent strain and deformation are 10-3,10-8 and 10-7 respectively,which fully meet the pre-designed requirements. |
