Optimal Design And Finite Element Analysis Of Steel Truss Bridge Joints

Bridge construction is in the stage of rapid development,and most of the bridge design is design experience-oriented,this kind of approach is the traditional design concept.In order to meet the current situation,the traditional design method needs to be changed and the active thinking should be adopted to deal with the optimization of the structure.Therefore,the idea of combining the theory of structural optimization design with the design of the bridge structure is introduced.This can not only better coordinate the economy but also ensure the safety of the bridge structure,which solves the hidden contradiction between the economy and safety.In 1960,mathematical programming method was used for the first time in the process of structural optimization,which realized the combination of technical theory and reality of optimization design.Structural optimization design in the direction of bridge engineering development speed is relatively slow,its development degree is not ideal.Its scope of application is also limited because there are many uncertainties in normal bridge construction.In addition,in the process of optimization design,the definition of the objective function is very complex,and the amount of calculated data will be very large.In this paper,the traditional optimization design of truss structures,through the topology optimization,first carries on the preliminary selection of objective optimization,topology optimization and thus concluded that a node to the new contract end of truss structures,so after optimization operation is based on the node location,also said that directly to the node of steel truss structure optimization design,The minimum weight of the truss structure of Q235 steel,Q345 steel and Q420 steel varies with the degree of section contraction,and with the increase of section contraction,the mass of the truss structure of Q235 steel,Q345 steel and Q420 steel decreases by 6.1%,8.9% and 10%,respectively.Introduction section shrinkage parameters and node other sizes as design variables,the quality and the size of the equivalent stress as the objective function,to achieve the minimum quality and equivalent stress of the rationalization of the two goals,finally,verify the feasibility of the optimization results,from the point of axial force and shear force,as the degree of cross section shrinkage,maximum axial force increased by 3%,But the shear force is reduced by 30-40%.In addition,the bending moment is reduced by 60-65%,and the local and global stability is verified by buckling analysis,which fully proves that the structure is feasible.To pass the final validation,proved that the new contract section of the nodes of the truss structure is reasonable,and the mechanical properties and the cost optimization,this paper studies a new type of truss structure,and mainly in the node location is optimized and change,including the appropriate weight increase contraction strength is more advantageous to steel truss optimization,Because the high strength steel will cause the cost to increase,so the improvement of the strength of the shrinkage section steel needs to be moderate.The research results of this paper provide a theoretical basis for the application of the new type of truss structure with the joint form of the shrinkage section in practical engineering.