The Study On PCR Pattern Noise Simulation

With the development of economic and improve of people’s living standard, noisepollution could do serious damage to human life and healthy. When the vehicle speed isover50km/h, tire noise becomes the main part of travelling noise.In order to manufucture safety and eco-friendly tires, most countries formulaterelative laws and regulations, the most important and strict is EEC R117, and it will beforced executed in Nov.1st,2012. China also has similar regulation GB1495-2002.Tyre noise study starts from70th last century. It is thought that there are threecategories about tyre noise, one is pump noise, one is vibration noise and the other isaerodynamic noise. Whatever, each category has been researched deeply.Based on the previous works, we think pattern noise is the main part of tire noise.Air in the pipeline has special transmission characteristics. We can calculate theacoustic impedance at any position of the pipeline, and then we can use it to computenoise power. The groove can be divided into a number of small pieces, and we cancalculate the acoustic impedance Z and air vibration velocity U of each chop byempirical formula, and U has some connection with groove angle α, tire rolling speedv, contact area and distance to the front side of contact area. And the powerP=Re(U×Z×U). It must be noted here that, all parameters are calculated infrequency domain. Therefore, the entire formula calculations are performed in thefrequency domain totally.After finishing the calculation of noise mean power, we can get frequency domaincurves, and then precede low noise analysis. There are many different ways to low noisedesign, and we can find the optimum pitch arrangement by rules and high-speedcomputers.In summary, tire noise simulation system put forward a new computing methodbased on noise theory. However, the pump noise doesn’t equate the whole tire noise.Therefore, there is still difference between the computation and experiment results, butwe can make sure there is a strong relationship between them, and it can be used toguide low noise tire design.