Body and two-degree-of-freedom vibration system This article uses a two-mass system vibration model of body and wheel, as shown. The model can better reflect the vibration of the vehicle body m2 and the wheel m1, and is closer to the actual situation of the vehicle system. Its differential equation of motion is m2x. According to statistics, the road pavement spectrum of our country is basically within the three levels of A, B, and C. The relatively poor grades of the B and C roads account for a significant proportion. Vehicle parameter value Tab.1ParametersoftheVehicle Parameter value m1/kg1.0103m2/kg11.0103k1/(Nm-1)5.0106k2/(Nm-1)5.0105c2/(Nsm-1)1.5104 Take grade C road surface Gq(n0)=25610 -6m2/m-1, the speeds are 30km/h, 50km/h and 70km/h, respectively. The power spectrum of the wheel's random dynamic load is as shown. The power spectrum of the random dynamic load of the wheels at three vehicle speeds shows that there are two resonant peaks in the random dynamic power spectrum of the wheel. When the excitation frequency f is close to f1=k2/m2/2=1.07Hz, low-frequency resonance is generated, and the peak value of the wheel dynamic load is relatively large. The resonance peak value caused by different vehicle speeds is proportional to the vehicle speed, and the resonance frequency in the resonance region is relatively narrow, and the reduction occurs. The stiffness of the small suspension can make f1 smaller, which is beneficial to reduce the dynamic load of the wheel; when the excitation frequency f is close to f2=(k1+k2)/m1/2=11.81Hz, high-frequency resonance is generated, and the resonance frequency of the resonance region is For a wide range, the peak value of the wheel dynamic load is only about half of the peak value at low-frequency resonance; when the excitation frequency f>2Hz and f when the vehicle speed is 70km/h, the vehicle travels on three different grades of roads A, B and C. The power spectrum of the random dynamic load is as shown. When the excitation frequency f is close to f1, low-frequency resonance is generated, and the excitation range of the low-frequency resonance region is small. The power spectrum of the random dynamic load of the three kinds of road surface on the C-level road surface is much larger than the peak of the A-level road surface; High-frequency resonance occurs when the oscillation frequency f approaches f2, the excitation frequency in the high-frequency resonance region is relatively wide, and the dynamic load of the wheel is proportional to the road surface roughness. The peak value in the case of the Class C road surface is approximately 18% of the peak value in the A-grade road situation. Times. Conclusion The vehicle driving conditions are complex and varied. Using the latest scientific and technical methods to predict the instantaneous driving status of a vehicle is one of the objectives pursued by modern vehicle design. The evaluation indicators of vehicle ride performance include the weighted acceleration RMS value, the impact suspension limit probability, and the wheel dynamic load. The requirement for smoothness response to vibrations is sometimes based on probability distributions. For a linear system, since the random input of the road surface basically conforms to the normal distribution, the vehicle design engineer can use this method and the probability integral table to predict the probability that the dynamic load of the wheel exceeds a certain threshold value. Nonwoven Swabs,Alcohol Prep Pad,Medical Alcohol Prep Pad,Alcohol Prep Pads Shaoxing Lifecare International Trading Co., Ltd , https://www.sx-lifecare.com