Vibration Reduction Test And Parameter Optimization Of Magneto-rheological Damping Floating Slab Track

In order to solve the phenomenon of vibration amplification at the natural frequency of the traditional steel spring floating slab track and make up for its lack on low-frequency vibration damping,this paper introduces the magnetorheological(MR)damping vibration isolator into the steel spring floating slab track.Through the UM-Simulink co-simulation model and the original scale indoor floating slab track vibration damping test,the damping effect of the MR damping vibration isolator in the floating slab track system is verified;in order to further realize the practical application of the MR damper in the subway Application in operation,using the vehicle-track coupling dynamics theory to analyze the optimal parameter design combination of MR damping vibration isolators under different operating conditions.The main research results and conclusions of this paper are as follows:(1)First,the mechanical model of the MR damper was tested through indoor experiments,and the parameter identification of the Dahl model was modified with the energy recognition method,and the parameterized model was established through Simulink;the MR damping was achieved through UM-Simulink co-simulation.The local model of the device is introduced into the floating slab system,and the influence of different loading amplitudes on the vibration damping effect of the MR damper is simulated and analyzed,which lays the foundation for the development of the indoor vibration damping test.(2)Fix the MR damper between the floating slab and the foundation by installing fixtures on both sides of the floating slab,and use the circuit control system to control the MR damping output.Using the laboratory electromagnetic servo loading system,the indoor original scale steel spring floating slab track sweep test was carried out.The test results show that the introduction of MR damper in the floating slab track will weaken the displacement and acceleration amplitude of the floating slab to a certain extent;with the increase of the external current of the MR damper,the vibration damping effect decrease at the natural frequency is better,the maximum acceleration vibration level at the natural frequency of the floating slab can be reduced by about 4.0 d B after the introduction of the MR damper;and the introduction of the MR damping isolator can also reduce the basic acceleration vibration level in the low frequency.The maximum reduction is about 3.9 d B.The test results prove that MR damping can simultaneously achieve the optimization effect of vibration reduction at the natural frequency of the floating slab track and foundation.(3)Through the vehicle-track coupling dynamics model,the damping effect of the MR damper under different operating conditions is simulated and analyzed.The calculation results show that the subway operating conditions are very important to the design of the key parameters of the MR damper.The correct parameter design can not only effectively suppress the vibration of the floating slab,but also effectively reduce the maximum amplitude at the natural frequency of the force under slab.Regardless of the operating conditions of the subway,the MR damper must be matched with the control strategy,otherwise it will cause the medium and high frequency amplification of the under-slab reaction force.However,the displacement threshold in the control strategy is the opposite of the vibration damping effect at the natural frequency of the floating slab.The existence of threshold will reduce the damping effect at the natural frequency;the maximum damping force of the MR damper mainly depends on the track irregularity and the speed.The worse the track irregularity and the closer the vehicle passing frequency determined by the vehicle speed is to the natural frequency,the higher the maximum output value required by the MR damper.