Research On On-line Measurement Of Track Bed Stiffness Under Dynamic Stability Vehicle Operation

As an important parameter for the quality evaluation of track bed,the current common methods need to remove the fasteners for measurement,which has complicated process and low efficiency.As an important large-scale railway maintenance machinery,dynamic stabilization car plays an important role in the quality improvement of ballast track after new construction and overhaul.Its main purpose is to rapidly improve the compactness of ballast,and then improve the vertical stiffness and transverse resistance of ballast.However,the current dynamic stabilized vehicle still has some deficiencies,the determination of the working section of the dynamic stabilized vehicle and the setting of the operating parameters mainly rely on the experience of the staff,and the lack of scientific data guidance.In view of the above problems,this paper focuses on the measurement of the stiffness of the track bed.Through static simulation analysis,the response surface model of track bed stiffness and elastic modulus of track bed,track stiffness and track bed stiffness is obtained.The influence of loading point and local variation of track bed stiffness on track stiffness is analyzed.According to the above relation,the stiffness of track bed can be calculated by measuring the track stiffness,and a series of complicated operations such as removing the fasteners in the traditional measurement method can be avoided.The track stiffness under different rail types and different fastener stiffness is calculated by the formula,and compared with the simulation value,the deviation between the two is less than 5%.The track stiffness measuring device was designed and manufactured,and the track stiffness measuring test was carried out on the test track of CRCC HIGH-TECH EQUIPMENT CORPATION LIMITED,and the test results were compared with the simulation results.The stiffness of rubber pad is an important part of the track stiffness.The Moony-Rivlin model was selected in ABAQUS to simulate the rubber pad.The relationship between the static stiffness of rubber pad and the friction coefficient,the thick Ness of pad and the number of grooves of pad was studied.By establishing the dynamic model of ballast track,the influence of load parameters and track parameters on the vertical dynamic response of rail is studied.The mean square value of rail vertical acceleration is chosen as the characteristic value of rail vertical acceleration,and the relationship between the mean square value of rail vertical acceleration and the stiffness of track bed is obtained.The influence of load point and local variation of track bed stiffness on vertical acceleration of rail is studied.Finally,the dynamic model of dynamic stabilized vehicle-track-track bed was established.The loading wheels installed on the front and rear of the dynamic stabilized vehicle exerted vertical excitation force on the rail,and the vertical dynamic response of the loading wheels was measured.Due to the severe vibration of the dynamic stabilized vehicle in the working state,the operating parameters of the dynamic stabilized vehicle were changed in the simulation,and the vertical acceleration of the loading wheel was measured at the same time to study the influence of the operating parameters of the dynamic stabilized vehicle on the vertical acceleration of the loading wheel.The relationship between the mean square value of vertical acceleration of loading wheel and the stiffness of track bed is established.The principle and working flow of the measurement of the stiffness of track bed are designed.The research results of this paper have a certain guiding significance for the improvement of the static measurement method and the online measurement of the rigidity of the track bed.By measuring the stiffness of the track bed under the operation of the dynamic stabilized vehicle,the changes of the stiffness of the track bed before and after the operation can be timely held,and the operation parameters of the stable vehicle can be adjusted in time according to the changes of the stiffness of the track bed,so that the operation efficiency and effect of the stable vehicle can be further improved.