NUMERICAL ROUTINE FOR DYNAMIC ANALYSIS OF TRANSMISSION LINES GUYED TOWERS SUBMITTED TO BROKEN CABLE

In the design and sizing of guyed lattice metallic structures used in transmission lines (TL) as a way of simplification, static analyzes are usually carried, where the dynamic actions are represented by "equivalent static loads". However, the static response to this type of structure is not the most appropriate, since such structures are lightweight, slender and that are always subject to dynamic nature action, except the own weight. Therefore, a dynamic analysis is critical to get a more precise result in terms of efforts on the bars and nodal displacements. In this context, this paper deals with the development of a computational routine in Fortran, for obtaining the dynamic response of guyed metallic towers of TL, submitted to dynamic action of broken cable. For the solution of this problem is used the Direct Integration Method of the equations of motion, explicitly, whit central finite differences. In the output result files, the axial forces in all the bars are displayed along the time and the nodal displacements are recorded at certain intervals of time during the analysis, in order to facilitate the structural behavior viewing with animation in post-processing programs. The accuracy of the dynamic response is evaluated by analyzing the isolated guyed tower, subjected to an impulsive load, comparing the fundamental frequency, calculated on the top of tower displacements obtained in the time domain, at the same frequency determined by an modal analysis. Knowing that the method is conditionally stable, the stability is evaluated by analyzing two responses of the same model, obtained with two different integration time intervals and smaller than the critical interval, which must be identical