Adding diaphragm is a simple and effective way to strengthen transmission tower structure.However,the change of dynamic stability and the difference of failure mechanism of transmission tower after adding diaphragms are still not clear.Taking the ZY2 transmission tower in a 220 kV common tower double circuit transmission line for example,the finite element model of tower-line coupling system is established to compare the modal differences between tower and tower-line system before and after adding diaphragms.The results show that adding diaphragms at the intersection diagonal near tower leg joints could suppress the local vibration mode of transmission tower.Then,random dynamic wind field is applied to calculate the axial stress response before and after adding diaphragms at different tower sections under different wind speeds.So that the dynamic stability parameters of diagonal braces are calculated based on the theory of dynamic unstable region,which are drawn in the same parameter plane with the dynamic unstable region.According to whether the diagonal brace parameters enter the dynamic unstable region at a certain wind speed,the wind speeds at instability before and after adding diaphragms at different tower sections can be determined,which shows that adding a diaphragm can increase the wind speeds at instability by up to 3 m/s.
diaphragmtransmission tower-line systemdynamic unstable regionwind speed at instability
NETL
NSTL
维普
万方数据
