Research And Realization Of Portable Flaw Detection System For Train Wheels

With the continuous development of the domestic rail transport,new requirements are put forward for traffic safety.At present,the wheel inspection mainly relies on small handheld devices,which is not convenient.Also,small handheld devices are not comprehensive in the flaw coverage.In the meantime,large-scale testing equipment has some disadvantages of expensive,complex,inconvenient to carry and need to remove wheels.Therefore,developing a kind of portable intelligent testing equipment has far-reaching significance for Chinese railway development.Based on the research of ultrasonic testing technology and its application in wheel flaw detection,a portable inspection system for train wheel is developed.Ultrasonic flaw detection technology is studied firstly in this paper,and then the ultrasonic flaw detection model is built based on the train wheel.The system uses ultrasonic pulse reflection method as the train wheel flaw detection method,and through several experiments to extract the key technology of ultrasonic testing.On the basis of ultrasonic flaw detection technology,this dissertation has designed the hardware and software of the portable flaw detection system.The hardware part has focused on the design of data acquisition module,first,tested the performance of the probe and designed the layout of the probe,ensured that the probe array can scan the wheel tread and rim in a full range,then,an ultrasonic testing(UT)unit was designed,the analog signal can be filtered and digitized at high speed.The software system uses LabVIEW as the platform to complete the data collection,analysis and display.The wavelet signal is used to filter and reconstruct the ultrasonic signal,and the method of dynamic triangle is used to solve the problem of large angle drawing.Also,the 3D display of ultrasonic wave and the defect recognition method based on expert system are studied.The train wheel portable testing system proposed in this dissertation can detect the defects inside the rim,which can meet the technical requirements of the locomotive.At present,the system is in the trial operation stage and has been installed and debugged in Nanjing east and Jinan locomotive depot.The accuracy rate of defect detection achieved 90%,and users give a high degree of evaluation.The system has realized intelligent flaw detection,and solved the problems of complicated operation,low efficiency and incomplete coverage of the existing equipment.Also,the system has some advantages of convenient installation,high detection efficiency,low leakage rate,low misjudgment rate,which can meet the technical requirements of the railway company and all indicators of wheel flaw detection.