Study Of Multiple Repeated Tensile Stress Behavior Of Transmission Tower Nodes And Poles

At present,bolted connection is the main connection form of angle steel transmission tower,and its force deformation performance has an important impact on the overall bearing performance of the tower structure.Transmission tower due to repeated deformation and jacking correction construction,the bolt connection node will be damaged or even fail,which has a great impact on the safety of the whole process of jacking correction of transmission tower.Therefore,the research on the repeated tensile stress behavior of transmission tower bolt connection nodes and rods is important to improve the rationality of the accurate analysis model of transmission towers and to improve the scientificity of the structural safety assessment conclusions of transmission towers.The following results were achieved in this thesis.(1)This thesis takes L50×4 and L63×5 cross-sectional angle members commonly used in pylons as research objects,and studies the slip deformation of bolt connection nodes after aperture expansion under axial load,and obtains the force performance of bolt connection nodes in transmission line pylons under axial load;establishes a twoway mechanical model of node slip deformation under axial load considering bolt preload,screw and hole wall contact,and angle and bolt friction;compares simulation results with test results to verify the reliability of finite element analysis.(2)Developed a test device for transmission tower angle bolt connection nodes under reciprocating load,conducted a test of transmission tower bolt connection nodes under reciprocating load,and obtained the whole process force performance of transmission tower bolt connection nodes under reciprocating load;analyzed the residual deformation values of bolt connection nodes under reciprocating load by measuring the changes of residual deformation values of the components;compared and analyzed the magnitude of slip load values of bolt connection nodes under each level of cyclic load.(3)developed a loading device applicable to the reciprocal load test of the transmission tower angle steel rod,the reciprocal load under the action of the transmission tower rod force performance test,the typical transmission tower angle steel members in the mining area under the reciprocal load under the action of the angle steel cross-section,length to slenderness ratio,connection mode multi-influencing factors of the whole process of force performance analysis,to obtain the transmission tower rod in the reciprocal load under the action of the remaining load bearing capacity change law,the results show that: after the damage to the transmission tower rod after repeated action of the load,will aggravate the rod deformation,resulting in the accumulation of damage to the rod.(4)Using ANSYS finite element simulation software,a typical 110 k V 1B-ZM3 transmission tower finite element model in mining area is established,Combine39 spring unit is introduced,and the application of the bolt node slip mechanics model in the overall tower simulation after hole expansion is explored;using ANSYS finite element simulation software,the residual bearing capacity of the rod(according to the test,the bearing capacity is taken as 90%,75%,60% and 45%)is introduced into the overall transmission tower model,and the relationship between the support reaction force,horizontal support displacement,horizontal displacement of the main material,rod deformation and support displacement of the overall tower model is studied.This dissertation has 117 figures,39 tables and 119 references.