Research On Modeling Algorithm Of Heterogeneous 3D Lattice Structure Based On Implicit Surface Modeling

In recent years,the lattice structure has been widely used in aerospace models including space shuttles,satellites,rockets and so on,because of its excellent mechanical properties.However,due to limited by the processing technology,the types of lattice applied are few.With the rapid development of additive manufacturing technology,designers are allowed to design and manufacture lightweight lattice cells based on the functional requirements of aerospace products to achieve efficient combination of functions and light-weight.Therefore,in this thesis,based on the additive manufacturing technology,a modeling algorithm of heteromorphic lattice structure based on implicit surface is proposed,and conducts theoretical and experimental studies on the structure after modeling.First of all,the heteromorphic lattice units of this thesis are derived from periodic surfaces,which can be expressed by implicit function,so called implicit surface.In this thesis,three kinds of heteromorphic lattice units derived from implicit surfaces are studied,and a modeling method based on implicit functions is presented for the construction of these heteromorphic lattice structures.In addition,to make better use of such lattice units,the structural characteristics of these lattices have been studied,including the inclination,shape and gradient.Secondly,this thesis studies the lightweight application of the heteromorphic lattice structure.It means using the lightweight property of the lattice unit to replace the original solid part of the model with lattice units.When do fill operation,the filling region is needed.A similar contour bias operation is employed in this thesis to form the filling area.Then using the Poisson method reconstructs the lattice structure in the filling region.Thirdly,considering that most of the parts have external loads environment,this thesis proposes a new optimization method of shaping lattice based on load constraints.According to the stress distribution of the model,the lattice structure filling in the model is adaptively adjusted so that the strength and volume of the structure reach the balance optimization result.Ultimately,the stability of the model structure is guaranteed,while the volume and mass of the internal lattice structure are reduced,so as to complete the second weight loss optimization of the whole model.Finally,aim at the proposed modeling method and optimization method of lattice structure in this thesis,verification of lightest manufacturability and validity is respectively made.On the one hand,utilizing a metal 3D printer prints the lattice structures to prove the manufacturability.On the another hand,three experimental models are respectively designed for the three types of lattice structures in the thesis.Using the finite element method evaluates the model changes before and after optimization and demonstrates the effectiveness.