Aerodynamic Noise Characteristics And Noise Reduction Methods Of Non-pneumatic Tire Spokes

Tire noise is one of the most important sources of noise at high speed.The nonpneumatic tire(NPT)is a new tire design form with advantages of explosion protection,simple maintenance and low rolling resistance.However,when the vehicle speed is higher,the open spoke chamber will produce larger aerodynamic noise.Therefore,it is of great theoretical significance and engineering application value to study the causes of aerodynamic noise and the methods of noise reduction for NPTs.In this paper,a particular NPT type is taken as the research object.The threedimensional finite element analysis model of the tire and the flow field model around the air are established.The deformation of the tire under a vertical load is analyzed with the finite element software Abaqus,as a reference standard for improving the mechanical properties of the tire structure design.The computational fluid dynamics(CFD)simulation method is used to analyze the flow of air around a rolling NPT.The effectiveness of the CFD simulation model is verified by comparing the flow field simulation results with the related research both at home and abroad.Based on the flow field results calculated by CFD,the air resistance and resistance moment of the tire are extracted,and the Ffowcs Williams-Hawkings equation is used to predict the sound pressure level of the tire noise in the far field,so as to evaluate the aerodynamic noise level of the NPT.The layout and the surface structure of the spokes of NPTs have great influence on the aerodynamic noise of tires.In this paper,the contribution of different parts of the surface of the NPT on the sound pressure level of the aerodynamic noise is analyzed.The position of the main sound source is determined.From the angle of the vortex sound theory,the cause of the aerodynamic noise of the NPT is analyzed.Two kinds of structural design methods for reducing the aerodynamic noise of the NPTs are proposed.In order to reduce the aerodynamic noise of NPTs,a non-smooth structural unit is added to the surface of the NPT on the surface of the NPT by imitating the structure of the stripe with a static characteristic in the owl feather.By comparing the aerodynamic noise results of NPTs with different spokes,it is found that the noise pressure levels of the NPTs and the NPTs with the non-smooth surface structure are significantly lower than those of the original structure under the appropriate structural parameters.Meanwhile,the mechanical properties of the improved tire did not decrease significantly compared with the original structure tire,which proved the effectiveness of the two NPT spoke methods.