| Summary: | 碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 100 === When a car is driving on the wet road, the water film is created under the tires contacting on road. The water film would reduce the friction force exerting on the tires, and the reduction is more apparent as the driving is increasing. Then as the normal contact force approaches to zero, a phenomenon named as hydroplaning effect occurs. The hydroplaning phenomenon causes a vehicle easily slide in driving and then is prone to an accident. Hence how to avoid or postpones the hydroplaning from occurring has become a major concern to the producers of both vehicles and tires. And enhancing the expulsive ability of a tire from water has been considered as the most effective way to prohibit the hydroplaning from happening.
In this study, we attempt to use Finite Element commercial codes-LS-DYNA to simulate the hydroplaning for gaining an understanding of the expulsion of water of a tire with or without pattern. First, in the numerical experiment, the 195/65 R15 tires with smooth pattern and with patterns, which two different longitudinal grove widths are used. The results are compared with those of Okano& Koishi and the difference within 17%-25% is found, The difference, justifies our numerical process reliable. Further, the 205/55 R16 automobile tires are calculated. The results show that the hydroplaning occurs at a velocity of 116 km/hr for a tire with four longitudinal groves pattern and 94km/hr for a tire with smooth pattern；the former is obviously better than the latter. Finally, we study the remote control cars tires with two different patterns, dotted and V-shape treads. For the water film with thickness of 3mm, the hydroplaning velocity of the dotted-shape-tread about 60km/hr, and the hydroplaning velocity for the V-shape-tread falls between 40km/hr and 50km/hr, in 5mm water film of water of hydroplaning velocity are 40km/hr following.
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