Research On Grid Generation And Optimization Of Free-form Space Structures By Parameterization

In the new era,because non-linear architecture can enhance the ability to express emotions,the architectural form has been expanded and extended from linear to non-linear.The emergence of non-linear architecture represented by deconstructionism indicates that people’s aesthetic pursuits are changing.The designer hopes to arouse the public’s passion with a new architectural form.The spatial grid structure has gradually got rid of the constraint of the regular function surface shape,and the non-linearity and irregularity of the surface are more prominent.Because of its many advantages,such as structural efficiency,space flexibility,and rich aesthetic performance,free-form space grid structures are used in more and more domestic and foreign landmark buildings.With the continuous improvement of the human aesthetic level and the pursuit of architecture,new concepts such as structural exposure,integrated design of architecture and structure,structural aesthetics,and structural architecture have been continuously proposed and paid attention to.Therefore,for freeform surfaces,how to rationally divide and optimize the meshes to make the meshes evenly distributed,the length of the rods uniform,and the curves smooth,to meet the mechanical performance requirements of the structure,but also meet the aesthetic requirements and vision of the building effect,which can be realized efficiently in the end,is very necessary.Based on the above problems,this paper conducts a preliminary study on the grid generation and optimization of free-form surface space structure,and uses parametric technology to realize three meshing methods and two mesh optimization methods for different surfaces:(1)Based on the Grasshopper and Gh Python Script platforms,this article uses different evaluation parameters as the meshing targets,and writes a free-form space grid structure parameterized modeling program,and implements three meshing methods that adapt to different types of surfaces: the first kind,with the goal of grid uniformity and fluency,implements an improved mapping method based on surface approximation expansion.This method is mainly used for rotating curved surfaces.The surface approximate expansion method is an improvement proposed for this type of surface in this paper.Radiation mapping method;the second kind,with mesh fluency and integrity as the main goal,realized a multi-type mesh automatic division method based on surface parameter domain segmentation,and proposed a line segmentation based on main curvature line for complex opening surfaces The method of meshing after the surface;the third kind,aiming at the same rod length,proposes two types of automatic meshing methods for quadrilateral meshes of equal rod length based on the principle of spherical intersection,which are suitable for four-sided boundary surfaces and arbitrary boundary surfaces.The results show that the above method can obtain a grid with better fluency,more uniform grid size,and better shape quality.At the same time,parametric programming can output the model quickly and conveniently,and improve the efficiency of design information exchange.(2)The parameterization technique is used to optimize the geometry and mechanical properties of free-form surface grid structures,respectively,and the effect of grid direction on the mechanical properties of free-form space structures is analyzed in detail.The first one,aiming at the integrity of the boundary grid,realizes the automatic optimization of the mesh geometry based on the balance of spring elements and nodes.After optimization,the boundary grid integrity and uniformity are significantly improved.The second type is based on three types of curved surfaces(upper convex surface,concave surface,wavy surface)and considering different mesh shapes(triangle and quadrilateral)and support forms(peripheral support and single-point support).The static calculation of the grid structure model shows that the grid direction has a greater influence on the mechanical properties of the free-form space structure.On this basis,with mechanical properties(maximum displacement and strain energy)as optimization goals,an automatic optimization method of free-form space structure grid direction based on genetic algorithm was proposed.After the optimization of the grid direction,the mechanical properties of the structure have been significantly improved,and this optimization method has higher engineering application value.In a word,this paper explores various grid generation and optimization methods with the help of parametric technology,which provides theoretical support and method reference for the design and modeling of free-form surface space grid structure.