The Test Study Of The Modal And Vibratory Response Of The Cab's Suspension System Of A Truck

The light truck FD1071P4K which is researched and manufactureed by Wuzheng Group itself , when It's speed at 30-50km / h or so, the cab will appear vertical jitter and vibration from side to side, etc., because the vibration occurs in the normal speed range of the users, as a result the users have expressed dissatisfaction. Thus it makes the adverse effects of company's production and saling. In order to solve this problem, I am deeply involved in the planning and conducted systematic and comprehensive research.The subject is When the light truck models FD1071P4K at the speed 30-50km / h , the larger issue of vehicle will appears vibration, in order to solve the problem of the vehicle cab resonance, firstly, testing (body vertical or horizontal floor vibration acceleration signal) the vehicle through the low-- accelerated speed slowly (ie, slow scanning test), the result of it's resonance frequency is 3 ~ 4Hz.For the analysis of the resonance response which is related to the modal, we take the cab and chassis systems for modal test, measure it's each mode within 15Hz to find the modal resonance (rigid or elastic mode) , according to its modal vibration characteristics to improve the solution,ameliorate cab, then making the road test measuring the vibration of the cab,thus to evaluate whether it's improved.This article take the FD1071P4K vehicle suspension system as the object of study。First, carries on the cab system under the static condition the artificial excitation, and carry on the double channel fast Fournier transformation through the survey exciting force and the hip dynamic response (FFT) to analyze, obtain willfully between two spot mechanical admittance functions (transfer function). Through to experiments the admittance function with the modal analysis theory the curve fitting, distinguishes the structure the modal parameter, thus establishment system's modality model. Based on modal superposition principle, a variety of load time histories are known cases, the system can predict the vibration response of the actual process or the response spectrum.