The Design And Research Of Railway Track Stress Testing System

With the rapid development of subway and high-speed railway, In the late of track maintenance, Detection of rail temperature stress is crucial to the prevention of rail expansion and cracking of rail. In a timely manner to eliminate this risk on train running safety plays an important role. This project is based on the basic principle of Barkhausen, combined the effect of stress on Barkhausen signal,and completed the development of equipment for subway and high-speed railway stress testing.Firstly,this paper is based on electromagnetics, analyses the mechanism of Barkhausen signal generation, and the influence of tensile stress and compressive stress on Barkhausen signal. Then combining with subway and high-speed railway requirements, completed the design of the overall scheme of equipment development, including hardware, software and stress calibration experiment research. Hardware includes sensor and fixture, excitation signal generating circuit, Barkhausen signal conditioning circuit, data acquisition circuit, power module and smart control module. The software includes embedded software program design, host computer and lower computer serial communication design, aiming at the subway and high-speed railway application software design and data acquisition and processing program design. Stress calibration experiment research first identifies the relevant parameter of detection equipment, Mainly includes sampling frequency, sampling time, the amplitude and frequency of excitation signal and filter bands. Then focus on analysis of the influence of temperature on Barkhausen signal of two aspects, Proposed a new feature values of vertical and horizontal ratio, the new feature can weaken the temperature influence on the MBN signal itself; Then through rail under different load experiment,complete the quantitative calibration work of stress,and write down the equation. Finally, through the stress testing of existing rail, Calculate the difference between measuring value and the estimate value,then analyze the cause of this difference.