Research On Structural-borne Sound Transfer Paths Of Bogie

The wheel/rail noise is the main source of the interior noise.The structural-borne sound transmission via the bogie is an important transmission path of the interior noise.It is one of the methods to control the interior noise effectively to know the sound transmission characteristics and optimize the structure of the bogie.As a key system for connecting wheelset and body,the bogie has many springs,damping and connecting components,and the key to the study of the structure of the bogie is to determine the key sound transfer path and the sound transmission characteristics of the components.In this paper,the test method and the simulation are used to preliminarily explore the structural-borne sound transmission via the bogie.(1)Using the in-situ TPA method,the static transmission and dynamic response characteristics of the bogie are tested respectively.The frequency domain analysis model of the second suspension structure of the bogie is established,and the validity of the model is verified by comparing the measured and predicted target noise and the vibration results.Based on the validated model,the contribution of the two component suspension structures to the peak frequencies of vibration and noise is sorted.The results show that the main influence frequency of structural-borne sound transmission of the bogie studied is 0~400Hz,and the structural-borne sound is mainly transmitted along the bogie-longitudinal direction of traction rod-the car body,the bogie-vertical direction of traction rod-the car body and the bogielongitudinal direction of lateral damper-the car body.Because there is a certain coupling relationship between the longitudinal direcation of the traction rod and the lateral damper,The optimization of structural-borne sound transmission should be considered from the coupling of traction rods and shock absorbers.(2)Taking the arm as an example,by testing the lateral and vertical dynamic characteristics of the arm,the time domain calculation model of the lateral and vertical dynamic stiffness of the arm is established by using the four end parameter method,the partial fractional expansion method and the Laplace transformation method.And the finite element method is used to establish the finite element model of the helical spring,and the helical spring is simulated.Based on the static stiffness and mass characteristics,a multi-degree-of-freedom models for characterizing the vertical dynamic characteristics of helical spring are established.(3)by considering the flexible vibration of the bogie,the dynamic stiffness of lateral and vertical direction of the arm and the vertical of the helical spring,a preliminary time-domain model of structural sound transmission is established.The measured wheel/rail irregularity excitation is applied to simulate the influence of the dynamic stiffness of the arm and the helical spring on the vibration of the bogie.The results show that the lateral effect of dynamic stiffness of the arm is larger than the vertical effect.Considering the dynamic stiffness characteristics of the arm,the vibration of the bogie increases in 200-700 Hz,and the modes near the bogie 555 Hz are excited,and the maximum deformation of these modes occurs near the arm trod.Considering the dynamic stiffness characteristics of helical springs,the single frequency peak of the bogie vibration appears at high frequency.The cause of the peak is that the modal characteristics of the helical spring are excited and the helical spring mode and the bogie mode are coupled.In the simulation model,using the modal of dynamic stiffness to simulate the sound transmission characteristics of the suspension structure is more appropriate.