| Tire hydroplaning has always been one of the important reasons that threaten the safety of vehicles traveling on wet roads.In rainy days,accumulated water on the road continuously impacts the tread,weakening the adhesion ability of the tire to the road,causing "hydroplaning phenomenon".As the direct part of the vehicle grounding,tire hydroplaning can lead to dangerous conditions such as side slip and loss of directional control.The theory of trench drag reduction and the principles of bionics provide a new research method for mitigating the impact of tire hydroplaning.Optimizing the macro structure of tire tread patterns based on the above theory can effectively reduce the dynamic pressure in the tread grooves,enhance the critical hydroplaning speed,and improve the hydroplaning performance of tires.Therefore,exploring the application of non-smooth grooves and bionic microstructures in the field of tire design is one of the important directions of this topic.In this paper,the 185/60 R15 radial tire is reasonably simplified and the tire-road contact model is established.The complex pattern tire model and contact model with the road are created.The reliability of the model is verified by radial load test and deformation comparison.The CFD hydroplaning model is created based on the tire grounding model,and the rationality of the hydroplaning model and simulation analysis process is verified by empirical formula.According to the drag reduction theory of flat grooves,non-smooth structures with different structures and regular arrangements were designed.The effects of different structures on the drainage performance of longitudinal trenches are compared from the perspectives of water pressure,shear stress,section turbulent kinetic energy,and wall velocity distribution.The simulation results show that the V-shaped groove and the quasi-periodic quintuple sequence distribution groove structure have the best drag reduction effect.Based on the optimal trench scheme at the bottom of the longitudinal groove,the correlation analysis of the main structural parameters is carried out by SPSS.The five parameters with high influence are selected and the response surface optimization model are built,17 sets of simulation test plans are generated,the optimization objectives are determined,and the optimal plan is obtained according to the fitting equation.Tire hydroplaning simulation was conducted to compare the fluid field characteristics and performance before and after optimization,it is found that the tread of the optimized non-smooth longitudinal groove tire is subject to lower dynamic pressure and shear stress,the range of high-speed fluid area is larger,and the critical hydroplaning speed is increased by 12.49%,achieving the goal of improving tire hydroplaning performance.In order to further improve the drainage capacity of the tread pattern,combined with the principle of bionics,a lotus leaf structure is added on both sides of the longitudinal groove.Various analysis methods such as wettability simulation,water flow simulation and hydroplaning simulation are carried out by using Comsol and Fluent software,to comprehensively compare the effect of different bionic microstructures on the drag reduction of the groove and the improvement of the hydroplaning performance of the tire.The results show that the immersion and adhesion of the fluid on the surface of the bionic scheme 3 is small,and it shows good hydrophobic characteristics.At the same time,the bionic micro-structure improves the flow rate of fluid in the groove,improves the drainage efficiency,and theoretically increases the critical hydroplaning speed of the bionic tire by 5.42%.Compared with the smooth longitudinal groove tire,the combined effect of the non-smooth bottom structure and the bionic microstructure of the side wall increased the value by 18.57%. |
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