The Ultimate Load Capacity Analysis Of Power Transmission Tower Structures

The power transmission tower is a form of high-order statically indeterminate space structure,and they are widely regarded as one form most difficult to be analyzed of all lattice structures.Using commercial finite element software existed, The ultimate load capacity analysis of transmission towers usually does not converge, especially when the towers enter the large deformation stage.In the present article a full-scale experiment simulation program on power transmission towers is realized.Using this program, the present article implements an ultimate load capacity analysis on full-scale experiment transmission tower ZC27102,and the simulation result is satisfactory.The full-scale experiment transmission tower ZC27102 is modeled with beam,shell and bar elements,in order to be closer to the real structure.The model load includes wind load, gravity of the tower and the pulling force of the transmission line.Finally the whole transmission tower is simulated using the program above.The finite element program uses 3D beam element and DKQ shell element.The 3D beam element is improved from Bathe's beam element,and suitable for plastic postbuckling analysis of L-shaped cross section beam.The DKQ shell element is formed with DKQ plate element and membrane element,and it can sovle the shear lock problem.The program based on Updated Lagrangian approach, considers geometric and material nonlinearity,to obtain the load-displacement relation curve of the transmission tower structure. In the program the Newton-Raphson's method is used to iterative computation,and the method of cylinder-arc-length is adopted to control the iterative process. It is shown that good agreement is obtained between the simulation result and the available experimental data. It is also shown that the shell-beam-bar model is more accurate than beam-bar model according to the comparison between the simulation results and the experimental data.According to the study in this article,the program is accurate and suitable for the elastic-plastic large deformation analysis of transmission towers.Finally Some useful conclusions are obtained,and an improvement on the program is suggested.