Research On Turnout Tip Rail Damage Detection Technology Based On Ultrasonic Guided Wave

As an important part of the railway,the turnout switch rail is easy to cause fatigue damage due to its special working position,and problems such as material loss and block falling often occur.Ultrasonic guided waves have the advantages of good propagation performance,long transmission distance,high complexity of applicable structure and low propagation loss,and are widely used in the field of track flaw detection.However,the existing ultrasonic guided wave detection technology can not accurately identify and judge the damage in the switch rail.Therefore,this thesis takes the switch rail as the main research object,and studies the propagation characteristics of ultrasonic guided waves in the switch rail,noise reduction and location of damaged signals in the switch rail.The main work is as follows:The simulation model of 60 AT switch rail is established to simulate and analyze the instantaneous dynamics of ultrasonic guided waves.According to the principle of ultrasonic guided wave detection method,the propagation characteristics of ultrasonic guided wave are analyzed by simulating the flaw detection method of one transmission and multiple reception.The node signals at different positions are selected for research,and the location error of damage is calculated by analyzing the signal modal characteristics of ultrasonic guided waves.The advantages and disadvantages of EEMD and VMD algorithms are studied in view of the variable cross-section structure of turnout switch rail and the dispersion phenomenon of ultrasonic guided waves.In the experiment of propagation characteristics of ultrasonic guided waves,VMD algorithm is used to decompose the waveform of ultrasonic guided waves and reduce noise.Through dynamic simulation analysis,the damage detection test scheme of ultrasonic guided waves is designed and improved,and the influence of different positions and types of damage in the switch rail on the propagation characteristics of ultrasonic guided waves is studied.The test results of ultrasonic guided wave point rail damage detection are analyzed,and signals are extracted from different parts and positions of turnout point rail to calculate the location error of damage.The simulation and test results verify the effectiveness of 100 k Hz ultrasonic guided wave propagation in the turnout switch rail and the ability of damage detection.The damage detection test of ultrasonic guided waves is carried out at the bottom of turnout switch rail,and the group velocity of ultrasonic guided waves in the bottom of switch rail is obtained,and the positioning error of damage is calculated.