Study On The Relationship Between The Distribution Of Force Of The Bolts And The Arrangement Of Bolts And The Pretension In The Transmission Tower

Transmission tower is a kind of space truss structure with many joints.Shear bolt connection is very common in the connection of transmission tower.When the shear bolt connection is in the elastic stage,the force of each bolt is uneven.Therefore,it is important to study the distribution of the force of the bolt in the working state,which is of great significance to design a bolt connection node with clear force,simple structure,safe and reliable.Based on the theory of elastic mechanics and material mechanics,the calculation formulas of the force of the bolts are derived,which are only axial deformation,only local deformation,axial deformation and local deformation;The finite element method is used to simulate the shear bolt connection system.The relationship between the force ratio of the bolts and the arrangement of bolts is obtained,and the relationship between the influence coefficient of the local deformation of the bolt hole and the arrangement of bolts is also obtained.Research shows that:(1)in the connecting member,if the deformation of the connecting plate is mainly the axial deformation of the plate,the connecting force is mainly transmitted by the front and rear rows of bolts,and the force of the middle bolt is very small;(2)if the deformation of the connecting plate is mainly the local deformation of the bolt hole,the connecting force is mainly transmitted by the total connecting bolts on average;(3)The actual force distribution of the connection bolt group is generally between the two cases,and the force distribution of the bolts in the connection is related to the arrangement of bolts.For the transmission steel tube towers,the connection between the main member and the main member is generally a flanged connection.Under the action of axial tension or bending moment,the flange is easy to be separated,and the bolt is easy to loosen.To apply a certain pretension to the bolt,the flange plate can be closely jointed,and the possibility of bolt loosening can be reduced while ensuring the integrity of the joint.Considering the influence of the bolt pretension,the calculation formula of the force of the bolt in the flanged connection is deduced based on the theory of material mechanics,and the law of the tension of the bolt with the external force is obtained;Considering that when the flange is tightly fitted,the neutral axis is in the center of the cross section of the flange,the calculation formula of the force of the bolt in the flanged connection is deduced based on the theory of material mechanics.