Optimization Of Thin Walled Structures With Complex Surface Constraints For 3D Printing

In order to meet the demand of processing technology,automotive parts structure design must give full consideration to processing constrains,resulting in not optimal design in structure and size aspects.The ideal optimal design can only be used as reference for the final design.However,3D printing technology's appearance makes the fairy tale "magic pen Ma Liang" becomes a reality.It can directly process the optimal design and ensures the final design be the optimal one rather than suboptimal one.Therefore the structural optimization design faced 3D printing is widely researched.Especially,for thin-walled structures,it is important to avoid using traditional equal thickness printing method,and make full use of the combination advantage of structure optimization and 3D printing technology.With the support of national natural science foundation,this paper researches the lightweight design of complex surface model faced 3d printing process from the thin-walled structure optimization design and minimal surface filling aspects.Focusing on the lightweight design of thin-walled structures with complex curved surfaces,a method based on the movable morphable component(MMC)topology optimization method is proposed for thin-walled structures with complex curved surfaces.In this method,the thin-wall structure is decomposed into an equal thickness outer surface skin and a variable thickness reinforced structure.The outer surface of the skin ensures the appearance demand of model.Reinforced structure is based on MMC topology optimization method.And it's improved by constructing a guide field and curved surface domain for realizing topology optimization on complex curved surface.In this paper,the Siemens NX platform is used to realize the automatic modeling and models with relatively smooth boundaries are obtained.The mechanical properties of the reinforced structure with different volume fraction were analyzed by finite element analysis method.The results show that the method has ideal optimization effect.For the application of biomimetic structure in automotive field,this paper discusses the structure of Triply Periodic Minimal Surfaces.The Triply Periodic Minimal Surfaces is minimal surface that has periodicity in an arbitrary direction of three directions in three-dimensional space and it can be infinitely extended.So structures composed of Triply Periodic Minimal Surfaces are isotropic.In addition to the advantages of good mechanical properties,the minimal surface has a smooth and continuous pore structure,and the pore structure is easy to control.In this paper,by comparing theexcellence degree of different surfaces under different evaluation indexes,we make lightweight design of the surface structure of the selected type from two aspects,the stiffness of thin-walled structure and the crashworthiness in order to obtain the optimal evaluation index of certain mass.The result shows that this kind of structure has little advantages of stiffness,but it has obvious advantages in the aspect of impact resistance.