Design And Performance Analysis Of High-load-bearing Heterogeneous Three-dimensional Lattice Fusion In Additive Manufacturin

The cross-generation development of high-end equipment in aviation,aerospace and other fields requires that the proportion of structure should be reduced from 25% to 10%,and the functional density should be increased from 30% to 60%.Lightweight design has always been the eternal theme of its pursuit.Traditional lightweight design technology has reached its limit,and it is urgent to innovate lightweight methods based on the limit.The deep integration of lattice structure and additive manufacturing technology has become a new way to solve this demand.However,how to realize the integrated design of structure and function based on 3D lattice according to the service conditions of high-end equipment has become the focus problem to be solved urgently in this field.Aiming at the ultimate lightweight design and manufacturing requirements of complex components,this paper studied the optimization design method of ultra-lightweight and high load Multi-lattice with the support of additive manufacturing process and the optimization of mechanical properties of lattice structure.Combined with geometric modeling,numerical simulation,structural optimization,performance testing and other approaches,the geometric high-order continuous design of Multi-lattice structure with high load capacity was realized,which provides theoretical basis and technical reference for the in-depth application of Multilattice structure in major engineering equipment.Major achievements include:(1)The modeling design method of Multi-lattice structure with high load was studied,and the optimization design strategy of Multi-lattice transition interface based on substructure parameter regulation was proposed,which realized the geometric high-order continuous optimization of arbitrary complex fusion boundary,and improved the connectivity between different lattice configurations.Experimental results show that the structural strength of the proposed method is improved by 52.2%,compared with the traditional Multi-lattice design method.(2)The size effect of lattice structure in finite space was analyzed.Under the constraints of manufacturing process,the mechanical properties of lattice structures increase first,then remain unchanged and finally decrease with the increase of scale factors.When the scale factor is 6-10,P-lattice structures have higher elastic modulus and strength,and show the best mechanical properties.(3)The influence of different lattice configurations and different ratio of lattice elements on deformation behavior and bearing capacity of Multi-lattice structures was studied,and an approximate prediction model of geometric parameter-young’s modulus was established to evaluate the fusion effect of Multi-lattice structures in transition region.The numerical simulation results show that the strength and modulus of the Multi-lattice are between those of the two substructures of the Multi-lattice.(4)An optimal design method of functional gradient Multi-lattice structures was proposed.The elastic scaling law of lattice structures was introduced as a material interpolation model for topology optimization to obtain the optimal density distribution of a specific lattice structure.Based on the performance differences of lattice structures in different orientation,the correlation mapping mechanism of stress and lattice types was established.The structure was functionally partitioned according to the principal stress direction to obtain the optimal configuration distribution of the design space,and finally the Multi-lattice structure with high bearing characteristics was formed.The results show that the Multi-lattice structure has strong stiffness,and the stiffness is increased by 14.8% and 20.1%,respectively,compared with the traditional gradient P-type and IWP-type lattice structures.(5)Taking L-shaped beam,Three-point bending beam and quadcopter’s arm structure as examples,the load-bearing characteristics of functionally gradient Multi-lattice were analyzed.The experimental results show that the flexural stiffness and flexural strength of Multi-lattice structures are improved by 31.0% and 21.3% compared with the traditional density gradient lattice design method.