The Design Method Study Of The Dynamic Vibration Absorber And The Application In Vehicle Vibration And Noise Reduction

The dynamic vibration absorber has been developing for nearly a century, which is widelyused in automotive field. The dynamic vibration absorber plays a particularly important role onthe problem of vibration noise occurring during the post automobile development period. Thevibration and noise of either the body and frame, or the suspension and transmission shaft can beeased by the dynamic vibration absorber. The effect of easing vibration and noise from thedynamic vibration absorber is directly determined by its parameters of location, mass ratio,inherent frequency and damping ratio. Therefore, it is necessary to study the location choice ofthe dynamic vibration absorber, the main system equivalent parameter identification of the installlocation and parameter optimization of the dynamic vibration absorber.Firstly, we have designed and processed a dynamic vibration absorber, with the mass,stiffness, damping adjustable. We obtain the adjusting range of the parameters through thedamping ratio and inherent frequency tests. Secondly, we use matlab programming to work outthe method of orthogonal polynomials, to identify the main system equivalent parameters of theinstallation location. Furthermore, we compare those parameters with results from the traditionalquality induction method, and the results show that the former of the two brings better effect ofmitigating vibration, with which both sides of the peak height around the origin of displacementfrequency response function are close, and is subject to the optimum condition of fixed pointtheory. Thirdly, we study the optimization method when the main system are under the conditionof single degree of freedom or two degrees of freedom coupling. We find out that when the mainsystem is for single degree of freedom, it has a good damping effect after using fixed point theoryto match the dynamic vibration absorber. While when the main system is under the condition ofthe modal coupling, using finite element software to modify and forecast the modal has a bettereffect on parameters optimization of dynamic vibration absorber. Fourthly, by the experimentscombined with the simulation calculation of rectangular frame and coupling frame, we researchthe differences and relations between the response amplitude point and vibration mode amplitudepoint, and compare their maximum amplitude in frequency response function and the grossenergy. We get the result of that, when there is a coupling mode, the dynamic vibration absorberinstalled in the response amplitude can inhibit the two peaks at the same time, with8.7%damping effect increase compared to installed in vibration mode amplitude point.Finally, we conclude the process of designing the dynamic vibration absorber, and use it tomatch the dynamic vibration absorber in the front-axle beam of subframe in a passenger car. Thenoise problem occurring in back row when full throttle accelerating to2500rpm is be well solved. After installing the dynamic vibration absorber, the frequency-response function of origin ofacceleration is decreased20.29%at86Hz; Amplitude sound transfer function decreases1.452dB/N; and at the condition of full throttle speed, the total pressure of the left ear of the backright passenger reduces2.936dB(A), which proves to us it has obvious vibration and noisereduction effect.