Rail straining and sensing method based on bidirectional strain matching fiber grating demodulating technique

Abstract

The invention discloses a rail straining and sensing method based on bidirectional strain matching fiber grating demodulating technique. The method can be used for monitoring the quantity of shafts, the weight of the wheels or the positions of trains in running as well as the single-point or multi-point strain distributing conditions of the track. Compared with the traditional matching fiber grating demodulating technique, the method is different in that two matching gratings are respectively arranged on the side surfaces which are close to the top and the bottom of a rail in the system; according to the bidirectional strain (pulling strain and pressing strain) acted on the two gratings, the monitoring sensitivity can be improved, and the problem of the cross sensitivity of the strain temperature of the fiber grating during measuring the rail strain can be effectively solved. The method is simple in structure and fast to sample. The method is also be suited to monitor the dynamic strain of the rail.

Description

Technical field: [0001] The invention relates to the field of fact monitoring equipment manufacturing for high-speed railways and ordinary railway systems, in particular to a method based on optical fiber sensing technology to realize the perception of the strain state of the track, and obtain the number of axles, wheel weight, position and railway track safety of the running train through analysis and processing. state and other information technology Background technique: [0002] In the operation of railway lines, the monitoring of track strain is of great significance. By monitoring the strain of the rail under the load of the train, the safety monitoring of the weight measurement, axle counting, positioning and track status of the train can be realized. Traditional strain measurement methods (such as using resistance strain gauges, electromagnetic wires, etc.) are susceptible to electromagnetic interference and have poor stability, while fiber grating strain sensors hav...

AI Technical Summary

Problems solved by technology

At present, common solutions include matching grating demodulation method and using filtering and differential methods to process data to eliminate the influence of temperature and noise, etc. However, the influence of temperature on strain measurement cannot be well eliminated sometimes after using these methods

In the traditional matching demodulation method, one of the gratings is generally installed on the track, and the other is placed beside the track or in the demodulation unit. This method is not a big problem at room temperature or relatively low ambient temperature, because the ambient temperature When the rail temperature is low, the difference between the temperature of the rail and the ambient temperature is small or basically the same, but when the ambient temperature rises to a certain level (such as a hot summer day), the rail temperature is generally about 20°C higher than the ambient temperature, and the temperature must be right at this time. The traditional matching grating strain measurement results have a great influence; and when the temperature fluctuation of the rail is large, the methods of processing data such as filtering and differentiation cannot achieve good results

Therefore, in these cases, the above-mentioned method still has some deficiencies in the use of high-speed railways.

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