Dynamic Stress Monitoring Of Rail Based On Wireless Sensor Networks System

With the continuous improvement of the speed and carrying capacity of the railway, the interaction between the wheel and rail is more severe, and the problem of train safety operation becomes increasingly serious. There will be stress in the rail while train wheels pass by. Problems can be found in time to guide the railway maintenance by real-time monitoring. However, at present, the dynamic stress testing system has many disadvantages such as poor anti-interference ability, low detection efficiency, large human input and non-continuous monitoring, which limits the application of the rail force monitoring system. In recent years, with the rapid development of wireless communication and intelligent sensor technology, wireless sensor networks are widely used in railway safety monitoring. In addition, based on wireless sensor network and strain measurement technology, the design accomplished the remote real-time monitoring of rail dynamic strain by the remote controlling of wireless sensor nodes and gateways. The specific research contents are as follows.(1) The finite element model of rail was established. The simulation and analysis of the dynamic strain of the rail waist under different wheel-rail action points were completed. The influence of the size and position of the wheel-rail force to the measurement of the rail vertical dynamic strain was analyzed. And the relationship between the vertical dynamic strain and the load was tested on the rail loading test platform.(2) The hardware and software of the wireless sensor nodes were optimized in the light of the harsh application environment of the high-speed railway. On the hardware, the acceleration nodes were used to detect the train passing by and trigger the wheel-rail force acquisition nodes to ensure the integrity of the rail dynamic strain data. On the software, the timing mechanism of node was improved, and remote upgrade of boot program was added to the node.(3) The wireless sensor network system was installed in the high-speed railway line achieving the real-time monitoring of the dynamic strain of the rail vertical. In addition, the reasons of the baseline drifting of the rail vertical dynamic strain were analyzed. And the wavelet transform was used to solve the problem of data base line drifting. Hence, the pure vertical dynamic strain signal was obtained to provide a reference for the study dynamic response of wheel-rail.