High-speed Vibration Simulation Analysis Of Non-pneumatic Tires

Non-pneumatic tires are a new type of tire that has emerged in recent years.Compared with traditional pneumatic tires,they do not blow out and have the ability to improve vehicle handling,grip and comfort,and have less rolling resistance,so they have great potential for development.The vibration problem under high speed conditions is one of the main problems facing the development of non-pneumatic tires.In this paper,based on the finite element analysis method and signal analysis theory,the high-speed vibration characteristics of non-pneumatic tires are studied,and the main research contents and results are as follows:(1)The dynamic finite element simulation model and simulation process of TWEEL non-pneumatic tire are established,and the vibration signals of three measurement points of the key component spokes and the vibration signals of ground reaction force are obtained,and the FFT technique is used to analyze the amplitude and frequency characteristics.The results show that the vibration of TWEEL spokes is symmetrical up and down with the middle node as the boundary,and the vibration in the middle is the weakest,and the farther away from the middle node,the stronger the vibration is;the ground reaction force spectrum forms a low frequency overtone,which explains the cause of the tire noise.The influence of the four spokes parameters on the vibration of the spokes is in the descending order of spoke curvature,spoke length,Inner-De Rad,and Outer-De Rad.(2)A model of UPTIS non-pneumatic tire with the same outer edge size,the same hub size and close vertical stiffness value as TWEEL non-pneumatic tire was established to compare the high-speed vibration characteristics of the two tires.The results show that: for the vibration spectrum of the three measurement points of the spokes,UPTIS almost does not produce high frequency vibration during high speed rolling,while TWEEL has obvious high frequency vibration and higher amplitude peak;for the ground reaction force vibration spectrum,UPTIS has only one characteristic frequency,while TWEEL has multiple characteristic frequencies,which indicates that TWEEL is more likely to be vibrated during high speed rolling compared with UPTIS.The comparison of the vibration spectra of the two tire spokes under different loads shows that the vibration amplitude of UPTIS is always maintained at a low level during the change from low speed to high speed,while the characteristic frequency and amplitude of TWEEL vibration are very sensitive to the change of load,and the increase of rotational speed will make the amplitude peak increase and the characteristic frequency move to high frequency.The comparison of the vibration spectrum of ground reaction force of two tires under different loads shows that the vibration amplitude of both tires increases sharply with the increase of rotational speed,and the characteristic frequency remains unchanged,but the number of characteristic frequencies of UPTIS is less than that of TWEEL.The above results show that the vibration characteristics of UPTIS are better.(3)The orthogonal experimental method was used to investigate the effects of three parameters,namely,the radius of curvature of the UPTIS spokes,the spoke tension angle and the spoke thickness,on the vertical stiffness and the spoke vibration of the tire,and to determine the optimal combination of the parameters.The results show that for the tire vertical stiffness and spoke vibration,the three parameters have the same effect on them,i.e.,the spoke tension angle has the greatest effect,followed by the spoke thickness,and the spoke radius of curvature is smaller,and there is an interaction between the three parameters,and there is a synergy between the spoke radius of curvature and the spoke tension angle,the spoke tension angle and the spoke thickness,and an inverse synergy between the spoke radius of curvature and the spoke thickness.The optimal combination of spoke parameters was determined by orthogonal experiment: 20 mm radius of curvature,110° spoke tension angle,and 10 mm spoke thickness.(4)A BP neural network based on genetic algorithm was used for the multiobjective optimization of UPTIS spoke parameters.The results show that the BP neural network optimization results reduce the vertical stiffness of the tire by 5.8% and the maximum amplitude peak of the spoke measurement points by27% compared with the orthogonal experimental optimization results.In the case of meeting the requirements of tire vertical stiffness,the maximum amplitude peak of the spoke measurement point decreases more,and the optimization results are effective.The final combination of parameters is 25 mm radius of curvature of the spokes,110° spoke tension angle and 9mm thickness of the spokes.