Research On Damage Detection Of Train Coupler Yoke Based On Acoustic Emission Technology

As the towing of the train gradually increases,the force between the vehicles increases,and the requirements for safety and reliability of various components of the train have been raised.The coupler yoke is a key part of the train.Therefore,it is necessary to detect the crack defects of the hook frame in time,and the traditional detection technology is difficult to perform real-time monitoring under the train running state.Acoustic emission detection technology is a dynamic non-destructive testing technology that has been successfully applied in many fields.In this paper,the train hook frame is taken as the research object.The acoustic emission signal generated by the crack of the coupler yoke is simulated by the combination of ANSYS/LS-DYNA simulation and Hsu-Nielsen lead-breaking experiment.The acoustic emission wave is studied in the coupler yoke.The propagation mechanism and sound source localization are used,and the wavelet transform is used to optimize the positioning of the frame.This paper has studied the following aspects:Firstly,ANSYS/LS-DYNA is used to establish the finite element model of the frame plate,and the equivalent excitation force is loaded at the corresponding position.The results show that the simulated wave velocity is consistent with the theoretical wave velocity,the effectiveness of ANSYS/LS-DYNA simulation coupler yoke acoustic emission is verified.At the same time,two parameters of velocity and acceleration of the particle are found to represent the propagation history of the acoustic emission wave inside the coupler yoke.Then the effects of load step and grid size on the simulated wave velocity and the propagation characteristics of the acoustic emission wave inside the frame plate are studied.Secondly,the wave velocity is measured on the frame plate,and the wave velocity is measured under the conditions of the presence or absence of the magnetic suction seat,the middle position of the frame plate and the edge position.The results show that the presence or absence of the magnetic attraction seat has little effect on the wave velocity,and the deviation is 1%;The positional wave velocity will affect the deviation by 3.4%.The plane time difference positioning method is used to locate the lead-free sound source of the frame plate,and the positioning is good with an error of 4.91 mm.Finally,ANSYS/LS-DYNA is used to simulate the propagation characteristics of acoustic emission waves in the frame curved plate.Then the frame curved plate is flattened into a flat panel for simulation,and compared with the simulation results of the frame curved plate.The results show that the planar time difference positioning method is also applicable to the frame curved plate.Then,the plane sound source localization experiment is carried out on the frame curved plate by the plane time difference positioning method.The results show that the sound source localization is realized on the frame curved plate,but the error is too large,and the average error is 11.92 mm.Finally,the modal of the acoustic emission waveform is analyzed by wavelet transform,and the modal wave in the waveform is used to optimize the positioning result of the frame curved plate.In this paper,the combination of ANSYS/LS-DYNA simulation and lead-breaking experiment is used to study the propagation characteristics and sound source localization of acoustic emission waves in the coupler yoke.In order to use the acoustic emission technology to detect the damage of the coupler yoke,the theoretical basis is laid.