| As the main carrier of power transmission in power system,the safe operation of transmission tower system is related to social stability.Transmission tower is a typical high flexible structure,and its natural vibration period is close to the predominant period of wind load,so wind load is one of the main reasons for the collapse of transmission tower.In addition,due to the uncertainty of material parameters,size parameters and the randomness of wind load,the wind-induced response and bearing capacity of transmission tower system are highly uncertain.In this paper,considering both the structural uncertainty and the randomness of wind load,a structural vulnerability analysis framework based on Kriging surrogate model and IDA analysis is proposed.The purpose is to quickly obtain the structural vulnerability and collapse probability of any tower line system under actual wind load.The main contents are as follows:(1)When only considering the structural uncertainty,the vulnerability analysis of the equivalent tower line model is carried out.Compared with the deterministic model,the relative error of the collapse basic wind speed and displacement is only 1.7% and 1.1%,which verifies the correctness of the vulnerability analysis method and the rationality of the selection of structural parameters standard value in the design stage of transmission tower.(2)The Kriging surrogate model is established to simulate the collapse wind speed and collapse displacement of the system.The relative deviation between the prediction results and the finite element calculation results is less than 5%,and the cross validation errors of the two surrogate models are 4.1% and 3.5%,respectively.It can be seen that the Kriging surrogate model has high accuracy in predicting the bearing capacity of the structure.(3)Based on the uncertainty model established by LHS sampling,the structural vulnerability is analyzed under different conditions.The results show that: with the increase of wind direction angle,the collapse critical wind speed and variance decrease gradually;when the horizontal span increases,the collapse critical wind speed decreases by 31.2%,and the structural vulnerability increases at the same wind speed level.(4)Based on Newmark-β method,a time history analysis program for numerical model of transmission tower system is compiled.The results of the program are in good agreement with those of ANSYS.Considering the randomness of wind load,the structural vulnerability is analyzed based on IDA analysis and Kriging method,and the collapse wind speed is 0.83 times of the static nonlinear analysis;the uncertainty of structural parameters will lead to the high uncertainty of tower bearing capacity,and the wave amplitude of collapse wind speed is 11.9%.It can be seen that the two kinds of uncertain factors have great influence on the vulnerability of transmission tower system. |
