考虑环境因素并基于实测频率的输电杆塔损伤识别

Damage Identification of Transmission Tower Considering Environmental Factors and Based on Measured Frequency

环境温度和湿度对结构频率有明显影响,但是目前关于环境因素对输电杆塔结构频率的影响规律研究较少,导致传统的结构损伤识别方法精度偏低。对一个实际输电塔进行长期健康监测,获取不同温度和湿度下的结构动力信号,并进行频谱分析。根据实测结构频率,采用响应面法对输电杆塔进行模型修正及损伤分析。基于实际监测数据分别建立了输电杆塔的“温度-频率”和“湿度-频率”关系模型,研究环境因素对输电塔一阶频率的影响,并为基于频率的结构损伤识别提供修正方法。结果表明,输电塔一阶频率与环境温度呈正相关,而与环境湿度呈负相关。根据关系模型剔除环境因素影响之后的结构损伤程度与真实情况更加吻合,在实际结构健康监测和损伤识别中应重视环境因素的影响。

Environmental temperature and humidity have obvious influence on the structural frequencies,but there are few researches on the influence of environmental factors on the structural frequency of transmission towers,which leads to the low accuracy of structural damage identification.The frequency spectrum of different environmental factors of the transmission tower is obtained for long-term monitoring.According to the measured structural frequency,the response surface method is used to modify the model and the damage analysis of the transmission tower is carried out.Based on the actual monitoring data,the“temperaturefrequency”and“humidity-frequency”relationship models of transmission tower are established respectively to study the influence of environmental factors on the first-order frequency of transmission tower,and the updated structural damage identification method is proposed.The results show that the first-order frequency of transmission tower is positively correlated with ambient temperature and negatively correlated with ambient humidity.According to the relationship model,the degree of structural damage after eliminating the influence of environmental factors is more consistent with the real situation.In the actual structural health monitoring and damage identification,attention should be paid to the effect of environmental factors.