Rapid Modeling Method And Software Development Of Nonuniform Lattice Structure For Additive Manufacturing

Additional Manufacturing Technology(AMT)can produce structures with highly geometrical complications,and it ensures the manufacturability of lattice structures with high load-bearing efficiency,which boosts the research of lattice filling structures.It has become an important research topic to develop the modeling method of lattice structures and geometrical parametric description form as well as generate the model file for AMT.However,the use of traditional solid modeling CAD software based on the boundary representation modelling method for the design of large-scale lattice structures is grossly inefficient and time consuming,and can lead to processing issues when the solid model is converted to STL facet model,such as loss of precision,hole in the facet model.Furthermore,the solid model file lacks parameterized information,which makes it hard to connect with the simulation optimization process.In addition,it was difficult for traditional CAD modeling software to satisfy the needs of large-scale lattice structures visualization,and the problem of poor rendering and interaction will occur,which will seriously affect the modeling efficiency.Therefore,it is of great significance to study a rapid geometry model generation algorithm and develop an efficient visualization software for large-scale lattice structure.To this end,this thesis studies from two aspects: the development of rapid geometry modeling method and the efficient visualization of large-scale lattice structure.A fast geometry modeling method based on the lattice cell bounding box is proposed,which realizes custom filling and conformal filling of facet model,solid model and surface model.At the same time,with the help of the level-of-detail(LOD)display technique and model blanking technique to automatically simplify the scale of the facet model,the problem of poor rendering and interaction of traditional CAD modeling software for large-scale lattice structure is solved.Finally,a large-scale lattice structure interactive modeling software TopoBench is developed.The research contents and results are as follows:(1)Lattice cell bounding box generation algorithm of complex structure.The lattice cell bounding box generation algorithm and parameterized lattice model generation algorithm for closed filling domain and open surface filling domain are designed and realized.The key configuration parameters and geometry parameters that determine the lattice structure are analyzed and confirmed.The standardized file format(.lat file)is used as a model file for parameterization of the lattice structure and is used as the core data stream for lattice structure modeling work flow.(2)Parallel hybrid geometry modeling algorithm(paraHGM)for lattice structure.A parallel hybrid modeling algorithm for directly generating STL files that contain lattice structure geometrical information is proposed,which realizes the rapid and automatic geometry model generation of lattice structure.The experimental result shows that while the requirement of the geometry model generation function is satisfied,the algorithm has good parallel efficiency and acceleration rate,and has a significant improvement in modeling efficiency.(3)Rapid interactive visualization method for large-scale lattice structures.The rendering problem which happens to the geometry model interaction of large-scale lattice structure is solved from three aspects: level-of-detail technique,interactive period facet blanking technique and vertex buffer object technique,and the effectiveness in the respect of the rendering frame rate is verified by a number of examples.(4)A rapid modeling and efficient visualization software TopoBench for lattice structures for additive manufacturing is developed.After integrating and encapsulating the large-scale lattice structure interaction modeling program and rapid visualization program realized in this article,a large-scale lattice structure rapid modeling and efficient visualization software TopoBench has been developed based on the MVC(Model-View-Controller)architecture system.The reliability and user-friendliness of the software in interactive lattice structure modeling is confirmed by several typical examples.