Damage Identification Of Transmission Tower Under Random Excitation Based On Cross-correlation Function

As the lifeline engineering, transmission line tower system is of great importance to the national economy and the people’s livelihood. To ensure the health safety and the status of service is of great significance. But the transmission line tower structure will be damaged and collapse frequently. Its security has been paid more and more attention. How to identify the structural damage has become an important issue for the scholars to study. At present, the technologies of structural damage identification based on structural vibration characteristics have made great progress. Because of the randomness of load and the incompleteness of measured data, damage identification method is not perfect. Research to the damage identification which is suitable for engineering has very important significance.This paper expounds the structural damage identification technique and analyzes the damage identification method based on vibration.The paper elaborates the concept of cross-correlation function and cross correlation function amplitude vector emphatically.This paper mainly discusses the transmission tower structure model by the numerical simulation.By reducing the stiffness of transmission tower structure unit to simulate the damage of structure. The paper use cross-correlation function amplitude vector of the acceleration damage identification method to identify the damage of transmission tower structure under the wind load. The main conclusions are following:1.In this paper, the method used is a kind of method based on the measured vibration response signal.The method only need to acquire the time response information of structures under random excitation and can be applied to random excitation for structural damage detection.The method is simple and is more suitable for online to test the structure. 2.The curve of cross correlation function amplitude vector about healthy structure has fixed form.After the structure is damaged,the curve will mutate.So we can use this feature to detect structure. 3.This cross-correlation function is calculated by using acceleration response amplitude vector,We can also use velocity, displacement,and strain response signal calculate the cross correlation function amplitude vector. 4.After structural damage,damage factor will decline, so we can determine whether the structure is damaged. 5.When the structural is damaged, the greater the degree of structural damage,the damaged factor is smaller.