A monitoring method of rail fastener reaction force based on iron pad strain

This research has successfully explored a monitoring method that does not necessitate modifications to the current structure of the fastening system and ensures that the intrinsic force distribution remains undisturbed, which is the pioneering use of Fiber Bragg Grating (FBG) strain sensors to test the strain of iron pads to reflect the force of fastener support points. Then, through the laboratory single-point loading test and finite element simulation, the feasibility of the monitoring method has been confirmed, and the resolution is higher than the traditional method. Subsequently, based on the experimental environment of high-speed railway commissioning, dynamic long-term monitoring research was conducted, and relevant calibration experiments and finite element simulation analyses were carried out. The experimental research and finite element simulation analysis revealed the superior ability of the method in capturing intricate data details, with the field experiment verifying a high resolution markedly surpassing other existing methods. Furthermore, by monitoring the same train, the data were found to be highly repeatable, which confirmed the ability of the monitoring method to stably reflect the dynamic behavior of the train. Overall, the monitoring method provided in this research could monitor the fastener reaction force in real time for an extended period and accurately record its periodic dynamic loading cycle pattern, which provides important data support for the structural health condition of the ballastless track and the safe operation assessment of trains.