Acoustic Load Identification And Vibration Transmission Analysis For A High-speed Train Bogie Frame Under Operation Conditions

High-speed trains have been widely used in China in recent years.With the train speed increased,the problem of vibration and noise is increasing outstanding,which affects not only the drivers' healthy,but also the passengers' riding comfort.It's known to all that wheel-rail vibration is a major noise source that contributes to the high-speed train interior noise.And the bogie structure is the only structural vibration transmission path from the wheel-rail system to the vehicle body,of which the frame plays an important role in the process of transmission.Therefore,acoustic load identification and vibration transmission analysis for a high-speed train bogie frame under operation conditions have great significance.Transfer Path Analysis(TPA)has developed more than one method in practical application,among them the traditional TPA method is generally acknowledged as the most precise one and many other methods are evolved on this basis.However,the traditional TPA method has some disadvantages such as heavy workload of testing and time-consuming on modeling.In order to reduce the workload of the testing,this paper proposed a method that combined the testing data with simulation tools to identify the acoustic load and analyze the vibration transfer characteristics of a bogie frame under operation conditions,and this method is also originated from the traditional TPA method.In this paper,a trailer bogie frame of a typical Chinese high-speed train is chosen as an object of study,analysis methods including theory,simulation and testing are adopted to identify the acoustic load and analyze the vibration transfer characteristics of a bogie frame.Firstly,modal parameters and frequency response functions of the frame are obtained by using the finite element simulation method.Secondly,the modal superposition method is used to solve the vibration response of the bogie frame in combination with the testing data.Finally,the load forces of the frame are identified by using the inverse matrix method,and then the power of load forces can be calculated.The results indicate that the methods used in this paper are very helpful in analyzing the source of vehicle noise and studying the path of vibration transmission,and some results may also provide guidelines for designing the new bogie structure and improving the performance of the existing bogies.The main work and conclusions of this paper are summarized as follows:(1)A brief introduction of the transfer path analysis method is made,a recent research review of the TPA method is summarized.Besides,load identification in the traditional TPA method is described in detail.Even though the traditional TPA method has high accuracy but its testing workload is heavy.In this paper,testing method combined with simulation method are proposed to analyze the vibration transmission characteristics of the bogie frame.Details of the testing and the FE model of the bogie frame are also introduced.Comparisons of the vibration response are made between the testing data and the simulation results to verified the validity of the model.(2)Taking a typical Chinese high-speed train as an example,in order to obtain the power of the load forces,the first step is to implement the testing to obtain the vibration and noise of the train.Then,a FE model of the bogie frame can be established by using ANSYS software.And then,modal parameters and frequency response functions are obtained by calculating the modal analysis and harmonic response analysis of the bogie frame.Meanwhile,the vibration response of the frame is calculated using the modal superposition method.In the end,the loads of the frame are identified by the inverse matrix method,and the power of load forces can be calculated.(3)The vibration transmission characteristics of the frame are analyzed by using the concept of the power exchange of the load forces.Results show that in the frequency range of 50~800Hz,among the joint points of primary suspension with the axle box rotary arm and the bogie frame,the nodal point of the axle box spring support and the primary vertical shock absorber possess the major loading force power exchange.The node of antiroll torsion bar support and the node of secondary vertical shock absorber support give the most important contribution to the loading force power exchange in the range of the connecting points of the bogie and the adapting pieces between the truck frame and the car body.