| Steel tube towers are widely used in UHV transmission line engineering due to their technical and economic advantages.The joints of steel tube tower are mostly semi-rigid joints.However,at present,in the mechanical analysis of steel tube towers,such semi-rigid joints are processed into ideal rigid joints or hinges joints.Therefore,studying the semi-rigid joints and its influence on the wind-induced dynamic response characteristics of the UHV steel tube tower can help more accurately analyze the structure of the UHV steel tube tower and improve its level of design,analysis and check,thus improving the safety and stability of the power grid and promoting the comprehensive construction of the strong smart grid.In this paper,the semi-rigid solution method of the joint structure is analyzed firstly.Then the UHV steel tube tower SJ3021 is taken as the research object and the stiffness value of the semi-rigid joints in the steel tube tower is calculated.In the ANSYS software,the stiffness matrix element is used to simulate the semi-rigid feature of the joints in the UHV steel tube tower.So the UHV steel tube tower model considering the semi-rigidity of joints is established and the truss and beam hybrid model is taken as contrast model.Then,the Davenport power spectrum is taken as the horizontal wave wind spectrum and harmonic superposition method is used to simulate the fluctuating wind with an average wind speed of 30 m/s at a height of 10 m,by which the wind load on the tower body,conductor wires and ground wires is calculated.On the basis of modal analysis,the dynamic calculation of the finite element model of UHV steel tube tower considering the semi-rigid joints and the truss beam is carried out.The results show that the semi-rigid joint does not change the mode shape of the UHV steel tube tower,but it affects its natural frequency to a large extent.Under the dynamic wind load,the semi-rigid joint has a significant influence on the bending moment of main members.It has a certain influence on the displacement of conductor(ground)wires hanging points as well as the axial force of main members,and the influence on the axial force of bracing members and cross-section members is relatively small. |
PDF Full Text Request