Study On The Optimization Design Method Of Cable Prestressed Grid Structure

In the design of the grid structure,whether it is the application of pre-stress or shape optimization,it is to make the structural system force reasonable and low cost.The two have the same purpose and different methods,which makes it possible to combine the two design methods.The shape optimization design of the prestressed grid structure can not only adjust the internal force distribution of the structure by applying prestress,but also further improve the structural bearing capacity and reduce the structural cost through the shape optimization.In this paper,the cable prestressed grid structure is taken as the basic research object,and the mathematical model of optimization design such as orthogonal prestressed prestressed grid and positively placed quadrangular prestressed grid is established.The calculation method of prestressed optimal value and structural shape optimization method in structure are derived,combination of the two methods creates a pre-stressed grid structure shape optimization design method.In this method,the two variables of prestress and grid shape are considered,minimum strain energy as the target,two-level optimization algorithm is proposed for different variables,the first stage is the optimization of the prestress value by minimizing the strain energy of the structure when the structure shape is determined,the second stage is the structural shape optimization based on the strain energy sensitivity of joints under the combined action of external load and prestress after the prestress value is determined.The two levels of optimization were carried out alternately until the prestressed lattice structure with the minimum strain energy was obtained.The method created in this paper is used to carry out numerical simulation for different types of prestressed grid structures.First,the prestress value of the cable is determined,and then the position of the node is adjusted in the height direction of the node and the three spatial directions of x,y and z according to the strain energy sensitivity of the node.The influence of prestress on the structure and the variation of the parameters such as strain energy,strain energy sensitivity,displacement and internal force during the adjustment of the node position are studied,the shape and mechanical performance of the structure before and after optimization are compared and analyzed.Numerical examples show that the optimal design method of cable prestressed truss structure can effectively improve the stiffness of the structure,enhance the ability of the structure to resist external forces and deformation,verify the correctness of the theory and method in this paper,provide a reference method for related design.