Design And Matching For Dynamic Vibration Absorber Of Car Suspension

This article studies on the design of dynamic vibration absorber (DVA) and combines project"the low-frequency comfort research and development of car". The study content of this article is relate to basic theory of DVA, evaluation methodology of automobile ride comfort, multi-body dynamics principle, test optimization design, finite element theory and test modal analysis etc.In this paper, based on the ride comfort study of some passenger car, the study is carried out. Vehicle road running test is implemented and the objective point is driver seat floor. The test full-vehicle should be driven straightly on the national road level B, the travel speed should be uniformly from 40km/h to 120km/h with an interval of 10km/h. the acceleration curves of the floor in the time domain can be gotten after the vehicle road running test, the PSD (power spectral density) of the acceleration can be gotten and analysed through the FFT transform. Via the method of one third octaves, the value of weighted RMS of the floor is calculated. The analysis consists of the vibration sources and the transfer pathway of vertical vibration which affect the vehicle ride comfort. The result indicates this vertical vibration is coupled by the road random excitation and the 14Hz vertical rigid modal of the front suspension system. Based on the actual structure of the test vehicle front suspension system, the multi-rigid-body model of the front suspension system is built in software Adams. The vibration transfer characteristics of the front suspension system is analysed, comparing with the road test data, the result indicate the model is correct and the front suspension system has great influence on the ride comfort of test vehicle.In this paper, based on the analysis of theory, structure, working way, application scope, evaluation methodology and effect factor of DVA, a DVA simulation design method is presented. This method is based on the vibration transfer characteristics and test optimization design method. Comparing with the DVA experiment design method, this DVA simulation design method has many advantages, such as good feasibility, low costing, high efficiency and small environment effect.A optimized parameters DVA is matched by DVA simulation design method. The sensitivity of each parameter is also discussed. The vibration transfer characteristics of the front suspension system with the optimized parameters DVA is analysed, the result indicates this DVA can significantly improve the vibration transfer characteristics of the front suspension system. In this paper, the influence of DVA's installation to the DVA location, the upper control arm, is also studied on by finite element analysis and test modal analysis. The result indicates this DVA does not result in the negative effects to the upper control arm.For verifying the vibration reduction performance, a vehicle road running test is implemented while the upper control arm is equipped with the optimized parameters DVA. The objective point is driver seat floor, via the method of one third octave, the value of weighted RMS of the floor was calculated. The result indicates the weighted magnitude of 40km/h-120km/h descends 1.3dB～1.6dB, the comfort level of 90km/h, 100km/h, 110km/h promotes a grade. It indicates this optimized parameters DVA can significantly reduce the forced vibration, improve the low-frequency car ride comfort. Meanwhile, the result indicates this DVA simulation design method can match the optimized parameters of DVA conveniently, quickly and accurately. It is an effective DVA design method which can be widely applied to the engineering application.