Dynamic Analysis Via FEM in Conducting Cables for High Voltage Electricity
Cables, Vibrations, Finite Element Method, Displacements.
In conductor cables, one of the main external agents that can lead to fatigue, and consequently the decrease in its lifetime, is wind excitation. The rupture of conductor cables causes enormous damage from the economic and social points of view. The objective of this work is to investigate the dynamic behavior of cable samples using the Finite Element Method. Modal and harmonic analyzes were carried out in order to find the resonance frequencies and understand the dynamics of the structure in the frequency range of 30 Hz. The solutions found via the Finite Element Method through the software ANSYS Mechanical APDL, were compared with existing studies in the literature to validate the results. The results from the modal and harmonic analyzes were very consistent with the existing results in the literature. Then, the modal and harmonic analyzes were performed for the frequency range from 0 to 65 Hz. Then, in the first transient analysis, impulsive loads were applied for a time of 50 s on the 13,385 m cable sample, in order to evaluate the transient response of the structure. It was observed that the closer to the supports (node 128) the greater the frequency spectrum when compared to the middle of the cable (node 513). Another observed fact is that the system responds to low amplitude frequencies. It was noted that the lowest frequencies induced the greatest displacements in the cable, which could lead to fatigue failure. Finally, the cable was sinusoidally excited at frequencies of 5.2205 Hz and 36.5 Hz, and it was noticed that the system vibrates harmonically at these frequencies.