Study On Morphogenesis Technique For The Double-layer Free-curved Surface Grid Structure

The development of architectural structure is closely related to the development of society.Nowadays,people's demand for excellent architecture is not only in terms of architectural function,safety and economy,but also in pursuit of good artistic effect.Due to the rich and unique free-curved surface modeling,which can meet a variety of architectural design requirements,the free-curved surface structure has been greatly developed in recent years,but the single-layer grid structure is still one of the common structural forms in the field of space structure.Compared with single-layer grid structure,double-layer grid structure more reasonable not only inherited the stress,the characteristics of great spanning capacity,it has better reflect on integral stiffness,to design new structure form,should ensure the construction and structure harmonious and unified at the same time,this article will study on morphogenesis technique for the double-layer free-curved surface grid structure,specific as follows:(1)Using B-Spline surface research can reflect the architectural intent double-layer free-curved surface,and the reference plane,extract double grid model,through the structure operation information,load information,support the restriction of reasonable setting,finishing to work double-layer free-curved surface grid structure forms the establishment of the initial structure model of creation method.The initial structure model is the basis of the structural formation method and plays a very important role in the structural formation process.(2)Establish a mathematical model of free-curved surface mesh structure shape with the objective function of structural strain energy,the coordinates of key points as control variables and the spatial conditions as constraints.Considering the relationship between the strain energy sensitivity of B-Spline surface key points and the coordinate sensitivity of each grid node,the mathematical expression of the sensitivity of B-Spline surface key points is derived,and a method for constructing the grid structure of double-layer free-curved surface is proposed according to the relationship between the strain energy of structure and the strain energy sensitivity of control points.Fortran language is used to compile the corresponding program to realize the iterative calculation of the method.This method adjusts the moving direction of nodes according to the characteristics of sensitivity,and changes the overall shape of the structure by moving the coordinates of key points,so that the strain energy of the final structure drops to a lower level,the strain energy sensitivity tends to zero,and the whole structure reaches a reasonable state of stress.(3)The feasibility of the method was verified by a simple example,the change characteristics of shape and mechanical properties in the process of morphogenesis were discussed,the characteristics of the method were summarized,and the selection of movement strategy was analyzed.(4)On the basis of summarizing the characteristics of the method,in order to improve the practicability of the method,it has been further expanded.The extended method is not only applied to the double-layer spatial structure,but also can be applied to the multi-layer grid structure,the single and double layer grid structure and other structural forms.This paper also discusses the application of this method in practical engineering,and through engineering simulation design,analyzes the shape characteristics and force characteristics of different types of grid structure in different types of initial structure creation method and structure shape creation process,and verifies the effectiveness of this method.In this paper,the author studies on free surface double grid structure for ms the creation method,simple,effective and practical,realizes the construction and structure of harmonious and unified,but also can be extended to multiple layer,single and double layer grid structure on the morphology creation,the method is highly innovative and practical in engineering.