Research of cable tension sensor with bypass excitation structure based on magneto-elastic effect in cable-stayed bridge

The health monitoring for large-type bridges is very important to itself safe, as an important index to evaluate the health status of steel cable framework in cable-stayed bridge, cable stress online monitoring is an accepted world-class issue. Both traditional pressure sensors and vibration frequency methods have their own shortcomings, which are hard to meet the demand of cable stress online monitoring. The new cable stress measure technique based on magneto-elastic effect has been an overseas study focus because of its outstanding advantage, but its sensor structure is main sleeve structure which is very difficult to fixing and maintenance. The new magnetic loop structure of bypass excitation is brought forward, and it will solve the problem of fixing and maintenance. Its principle and model are described; the factors of effect are analyzed in detail and reduced. Finally the experiment system is designed, and the experiment of pulling tension is carried on, the experiment results indicate that its dynamic characteristic is good, its repetition is better than 0.2%. It can meet the requirement of health monitoring of the cable tension on-line.