Research And Application Of Obtaining Frequency Response Function Of Neutron Structure In Transfer Path Analysis

Transfer path analysis(TPA)is a very effective method to study the vibration of vehicle system.The frequency response function(FRF)is the uncoupled FRF after the excitation source is removed.It is difficult to obtain the frequency response function for vehicle system.In this paper,a method for calculating the frequency response function of vehicle substructure is proposed.The frequency response function of the decoupled substructure can be obtained by using the frequency response function of vehicle system level,which can be used as the frequency response function of uncoupled substructure in TPA calculation.The dynamic equation of multi degree of freedom vibration system is decoupled by modal superposition method,and the displacement column vector of system response is obtained.Then the definition formula of frequency response function,frequency response function matrix and response amplitude formula of each point of the system are obtained.Based on the Generalized Prediction Method of frequency response function(FRF),combined with the fact that the vehicle vibration system has no external force input at the target point,a calculation method of vehicle substructure frequency response function for vehicle vibration system is introduced.Based on the system response amplitude formula and the frequency response function at the system level,the required decoupling substructure frequency response function is finally obtained Number.The target vehicle is excited by force hammer,and the accurate system frequency response function data is obtained through the optimization of coherence function and frequency response function estimation method.The frequency response function of the uncoupled substructure is obtained by decoupling the frequency response function of the system through the calculation method of the vehicle substructure frequency response function.The frequency response function of the uncoupled substructure measured by the reciprocity method from the passive side of the suspension to the sliding seat guide rail of the main seat is compared and analyzed.The results show that the two groups of data have good consistency.A transfer path analysis method of vehicle substructure frequency response function calculation method is proposed by combining the decoupling substructure frequency response function obtained by vehicle substructure frequency response function calculation method with the working load obtained by parametric load identification model in OPAX(Operational-X TPA)method.Compared with OPAX method,the results show that the proposed method can accurately identify the problem path and has higher accuracy,which further verifies the accuracy of the vehicle substructure frequency response function calculation method.When the vehicle substructure frequency response function calculation method is used for transfer path analysis,it can effectively avoid the problem of dismantling the excitation source,reduce the time cost,and further improve the TPA method.