Analysis Of Mount Characteristics Considering Amplitude-frequency Characteristics And Vibration Isolation Of Mounting System

As one of the excitation sources of the vehicle,the powertrain design and research on its vibration isolation performance is an important part of the vehicle NVH design.The reasonable stiffness parameters of the mount and the assembly relationship with other systems are essential for vibration isolation and noise reduction of the vehicle to improve ride comfort.This dissertation first introduces the amplitude-frequency characteristics and decoupling calculation method of rubber mount,and focuses on the amplitude-frequency nonlinear characteristics of hydraulic mount.for the nonlinear characteristics of the hydraulic mount,the inertial channel hydraulic mount is taken as an example.And the amplitude variation characteristics of the upper liquid chamber stiffness are analyzed,and the amplitude-frequency characteristic expression of the mount dynamic stiffness is introduced.Based on this,the modal analysis and decoupling calculation method of the mount system under nonlinear influence are proposed.this method is used to analyze the modal and decoupling degree of the powertrain hydraulic mount system under different amplitudes,and then the modal type discriminant and the vertical decoupling optimization goal are summarized.Secondly,based on a domestic pure electric vehicle,the analysis method and basic principle of the transmission path are elaborated,and the application of TPA analysis method in the treatment of automotive NVH is introduced,The model was tested on the drum test bench,and the vibration acceleration signals of the mount,steering wheel,instrument panel and seat rail were obtained.The transfer path model was established,and the transfer function of each path and the contribution of the source to the vibration of the target point through each transmission path were calculated,the conclusion that the vibration of the left mount and the right rear mount has a great influence on the vehicle,which provides a reference for further optimization.Finally,according to the TPA analysis conclusion of the test vehicle,the Isight and MATLAB software platforms are used to optimize mount stiffness with the decoupling degree of the mount system as the target,and the dynamics simulation of the powertrain mount system is carried out in the Adams/View module.The dynamic reaction force of the mount support before and after optimization is compared to illustrate the optimization.It shows that the optimization result can effectively reduce the vibration intensity of the target point in the car.