Research On Form Finding And Shape-state Optimization Of Monolayer Spoke Cable Net Structure

The monolayer spoke cable net structure has the characteristics of light structure and reasonable stress,and has broad application prospects.However,its development started relatively late,and the structural design theory system of this type of structure still needs to be perfect.Based on the parametric design concept,this thesis takes the monolayer spoke-type cable net structure as the research object,and uses the parametric design platform to study the two key issues of the monolayer spoke-type cable net structure and form optimization.Based on the analysis of the definition and advantages of parametric design,this thesis compares various parametric platforms to determine the Rhino/grasshopper platform as the research platform of this thesis.The finite element analysis software developed based on this platform was compared,and Karamba3 D was determined as the auxiliary tool for the research of this article.The determination of the initial shape and the geometric configuration of the zero state in the flexible tension structure is the most important issue in the design process of this type of structure.Aiming at the form-finding problem of the initial form of the monolayer spoke-type cable net structure.The monolayer spoke-type cable net structure has unique geometric characteristics.The geometric characteristics are analyzed and the principle of "three cables co-planar" is summarized.Based on this,the form-finding method of the monolayer spoke-type cable net structure is created.Aiming at the zero-state form-finding problem of monolayer spoke cable net structure,this thesis studies the inverse iterative method of cable structure form-finding and applies it to the zero-state form-finding problem of monolayer spoke cable net structure.Through the summary of the principles and processes of the above two forms of form finding methods,the corresponding programs are compiled on the rhino / grasshopper parametric platform,and the feasibility of the form finding method and implementation program of monolayer spoke cable net structure is verified by combining with the simplified calculation example of four supports.Aiming at the shape optimization of monolayer spoke cable net structure,Through the comparative analysis,the structural stiffness,cost and stress distribution are selected as the objective functions,and the Z coordinate of the monolayer spoke support node,the initial pretension base value HC and the pretension adjustment coefficient of the cable are determined as the design variables,the displacement limit condition,the stress limit condition and the cable relaxation constraint condition are selected as the constraint conditions,and the genetic algorithm is used as the optimization algorithm.At the same time,the programming of shape optimization is realized on rhino / grasshopper parametric platform,and the feasibility of the method is proved by a plane suspension cable example.Finally,this thesis introduces the engineering background of Qianjiang Olympic Sports Center,and completes the establishment of the parametric model of the roof of Qianjiang Olympic Sports Center.Based on the parametric model,genetic algorithm is used to optimize the initial shape of the roof structure of Qianjiang Olympic Sports Center,and the characteristics of the optimized structure are analyzed.Starting from the optimization design based on parametric technology,this thesis studies the shape determination and initial shape optimization of monolayer spoke cable net structure,which provides a certain theoretical basis and technical support for the application of this kind of structure.