Research On The Vibration Isolation Characteristics Analysis And Monitoring Technology Of Steel Spring Floating Slab Track

The steel spring floating slab track is a vibration isolation system that consists of a concrete bed plate with a certain mass and stiffness placed on steel spring isolators.It is widely used in urban rail transit to reduce the vibration and noise generated during subway operation and minimize its impact on the surrounding environment.Due to the unique structure of the steel spring floating slab track,traditional manual inspection methods can’t effectively determine the operational status of the floating slab.Therefore,researching and developing intelligent monitoring technology for the floating slab track is of great significance for determining the track’s operational status.This paper uses theoretical modeling and finite element modeling to study the isolation characteristics of the steel spring floating slab track.A monitoring system is established using the acceleration and angular velocity of the floating slab’s three-axis vibration as monitoring signals.The vibration signal of the floating slab is denoised and analyzed for multiple dimensions to lay the foundation for intelligent monitoring of the steel spring floating slab track’s operational status.A mathematical model of a single-degree-of-freedom system was used to analyze the vibration isolation principle and structural characteristics of the steel spring floating slab track.A theoretical model of the steel spring floating slab track was established,and the vibration transfer coefficient was derived.The influence of the stiffness and damping of isolator and clips on the vibration isolation performance of the steel spring floating slab track was studied through the transfer coefficient.A finite element model of the steel spring floating slab track was built using ANSYS software,and modal analysis and transient response analysis were conducted basced on this model.The impact of different parameters of the steel spring floating slab track on its mitural frequency and transient response was obtained.According to the analysis results of the vibration characteristics of the steel spring floating slab track and the actual working conditions,a monitoring system based on MPU6050 six-axis sensor and 4G wireless data transmission was designed.The software development for the acquisition,data format conversion,and packaging of the floating plate vibration signal was completed using the STM32F4 main control chip.Through the data pass-through protocol and cloud platform,remote data communication was established between the 4G gateway and the local server.The server-side multi-channel data receiving and storage software development was completed using the Python language.The installation and debugging of the six-channel monitoring experimental system were completed on the selected metro floating slab track section,and the remote real-time acquisition of the floating slab track vibration signal was achieved.The characteristics of the floating slab track vibration signal were analyzed,and the improved threshold function wavelet denoising method was used to complete the denoising of the floating slab vibration signal.The changing characteristics of the vibration signal were studied from both the time domain and the frequency domain,and the differences in the characteristic values of the sensor signals at different positions were analyzed.The combination of numerical integration and high-pass filtering was used to accurately determine the vibration displacement of the floating slab based on the vibration acceleration,and the changing trends of the vibration displacement in different directions and positions of the floating slab were studied.Based on the vibration interval,duration,and power spectrum of the floating slab vibration signal,the monitoring of train running information and running status was achieved.The principles of modal decomposition and Hilbert transform were discussed,and empirical mode decomposition(EMD)and variational mode decomposition(VMD)were used to perform modal decomposition on the floating slab vibration signal.The amplitude change characteristics of various intrinsic mode components of different sensors were compared and analyzed,and the intrinsic mode components that can accurately represent the floating slab state were determined.The intrinsic mode components were subjected to Hilbert transformation,and their timefrequency spectrum,marginal spectrum,and envelope spectrum were analyzed to obtain vibration signal characteristic information closely related to the operating state of the floating slab,laying the foundation for the monitoring of the state of the steel spring floating slab track.