Shape Finding Of Cable Membrane Structure Based On Particle Swarm Optimization Algorithm

As a new type of flexible building structure,the whole design process of cable-membrane structure generally includes shape finding analysis,load analysis and clipping analysis.Shape finding analysis is one of the key steps in the whole design process of cable-membrane structure,which is directly related to the reliability and safety of subsequent structural design.At present,there are three methods for finding the shape of cable-membrane structure,which are density method,dynamic relaxation method and nonlinear finite element method.With the rapid development of computer software and hardware,intelligent optimization algorithm is favored by researchers and widely used in engineering practice.Particle swarm optimization(PSO)is widely used for its simple principle,few parameters and easy implementation.Based on particle swarm optimization(PSO)algorithm,this paper analyzes the shape finding of cable-membrane structures,and studies the folding problem of cable-membrane structures.The specific research work of this paper is as follows:(1)After to the Dutch to optimize the target of minimizing the maximum bearing reaction force to impose on the membrane structure of the membrane surface initial prestress as optimization variables,such as cable,membrane material strength limit and structure stress and displacement and so on as the main constraint conditions,established the membrane structure based on particle swarm optimization algorithm for shape optimization model,based on MATLAB and ANSYS platform to achieve the optimization modeling and calculation process.Based on the particle swarm optimization(PSO)algorithm,the shape finding optimization analysis of three typical cable-membrane structures,namely,rotating catenary surface,saddle surface and rhomboid hyperboloid,is carried out.The results are compared with those obtained by the force density method,which verifies the correctness of particle swarm optimization shape-finding algorithm.Results show that the rotating surface of catenary and diamond hyperboloid initial prestress of the membrane surface of 20 N/cm,the initial prestress saddle surface the membrane surface is 10 N/cm,find a shape optimal result,the uniform stress distribution,minimum,maximum counteracting force and compared with the force density method,the method for quickly,and find the results of high precision,the diamond hyperboloid particle swarm in calculating the shape algorithm to find the node coordinates the results with the analytical solution of the maximum error is 4.67%,rotation of the catenary is 3.31%,both small force density method to find the result.(2)The load borne by cable-membrane structures after shape-finding analysis is generallyrealized through the stress redistribution on the membrane surface.Due to the flexible characteristics of cable-membrane structures,the folding phenomenon is a frequent problem in the load borne by membrane structures,which will affect the normal use of membrane structures and even lead to structural damage.Therefore,the problem of folding of cable membrane structure cannot be ignored.Based on the shape finding results of particle swarm intelligence algorithm,this paper uses the nonlinear finite element method to observe the number of folds,the stress on the membrane surface and the vertical displacement of the structure under the action of load by changing the size of the initial prestress applied on the membrane surface.The results show that with the increase of initial prestress,the fold of cable-membrane structure decreases until there is no fold under load,but the corresponding stress of membrane surface also increases.As for the rotating catenary surface,with the increase of initial prestress,the membrane surface stress of cable-membrane structure increases under the action of load,and there is no fold.The vertical displacement of rhomboid hyperboloid and rotating catenary surface under different initial prestress has little change.Therefore,within the allowable range,the initial prestress can be appropriately increased to reduce the occurrence of folds.