Development Of A Fatigue Test Device For Fiber Grating Strain Sensors For High-speed Rail Monitoring

The structural safety of high-speed rail tracks plays a very important role in high-speed rail operation.In order to accurately measure the force state of the track,it needs to install strain sensors in the rail trunk,telescopic regulator,turnout and other key positions to monitor the track service status in real time.The optimal choice is the fiber grating strain sensor,which has the characteristics of high precision,corrosion resistance,and it is not affected by electromagnetic interference.To ensure stability and reliability of strain sensor,for specific application conditions of high-speed rail monitoring,it can apply Fiber Bragg Grating Strain Sensor Fatigue Test Device to do reliability testing and experimental verification to the sensor.This paper analyzed the advantages and disadvantages of the traditional fatigue testing machine and studied the sense principle of fiber grating strain and the test principle of fatigue testing machine based on the industry technical requirements of high-speed rail track strain monitoring.For the use conditions of fiber grating strain sensor and the actual needs of structural fatigue testing,a small strain sensor fatigue test device based on embedded system was designed.This paper used the Tiny 6410 core board instead of the traditional PC control mechanical linkage and developed a control interface based on Qt Creator software.Among them,the mechanical movement part used stepper motor to drive the crank connecting rod to achieve reciprocating motion,to make equal strength cantilever beam to produce deformation.The device set the amplitude of motion of two ranges of 5mm and 10 mm,and it was also possible to change the range by adjusting the length of the equal strength beam.When the equal strength cantilever beam reciprocated,it would drive fixed in the above fiber grating strain sensor to achieve fatigue testing.The device is stable and reliable and can be used for high-speed rail track with fiber grating strain sensor to do reliability test for different frequency or different fatigue times after the actual test.In this paper,the fiber grating strain sensor fatigue testing machine has the characteristics of small volume,easy to carry and easy to operate.It is suitable for fatigue testing of strain sensor research and engineering production,and it has a good application prospects in the field of high-speed rail track safety monitoring.