|Abstract: ||水滑現象(Hydroplaning)是造成車輛失控打滑的主要原因之一；車輛行經積水路面時，若胎紋之排水性能不佳，流體之動壓浮力會將胎體向上抬起，導致輪胎與地面之正向接觸力下降，產生水滑現象。再者，輪胎於濕路面煞車時，若其濕抓地力性能不足，將導致煞車距離過長，進而引發車輛碰撞問題，因此，提升輪胎之排水與濕抓地力性能，為目前各輪胎廠之重要研究課題。 因應歐盟ECE R117之轎車輪胎濕抓地力規範，以及對輪胎排水性能之掌握，本文以有限元素商用軟體LS-DYNA建置一套濕抓地力分析程序，針對光頭胎、三種直溝花紋胎與三種直溝混合花紋胎等七種花紋之轎車輪胎，分析其濕抓地力性能，並以水流模式分析法，模擬三種同溝塊比、不同幾何形狀花紋之轎車輪胎排水性能。由所得結果發現，三直溝胎之濕抓性能與四直溝胎相近，但帶貫通型橫溝之三直溝胎相較於帶貫通型橫溝之四直溝胎優秀許多；而在排水性能方面，四直溝胎之水滑速度為105km/hr，優於V型花紋胎之101km/hr，以及人字型花紋胎104km/hr，但四直溝胎之正向接觸力於中低速時下降太劇，故人字型花紋胎為較可靠之排水型輪胎。|
Hydroplaning is one of the main reasons causing vehicles to skid. When a car is driving on the wet road, if the tire’s capability of water-expulsion is low, the hydrodynamic will lift the tires up, and the normal contact force of the tire against the road approaches zero, which results in hydroplaning. Further, when braking on the wet road, if the wet grip performance is insufficient, it will result in longer braking distance and car accidents. Therefore, enhancing the tire's wet grip performance and capability of water-expulsion is critical to tire manufacturers. In response to the European ECE R117 of tire’s wet grip regulation, and the control of the tire’s capability of water-expulsion, this study uses the Finite Element Commercial Code, LS-DYNA to conduct a wet grip simulation procedures for analyzing the wet grip performances of seven tread patterns of the passenger car tires, such as smooth pattern, two four-longitudinal-grooves-pattern with different spacing, three-longitudinal-grooves-pattern, and three different longitudinal-transverse grooved pattern, and uses the flow model analysis for simulation of water-expulsion capabilities of the three kinds of the same groove-block ratio with three different geometries of the tread pattern tire such as, four-longitudinal-grooves-pattern, V-shaped pattern and人-shaped pattern. The results show that, the wet grip performance of three-longitudinal-grooves pattern and four-longitudinal-grooves-pattern are similar to each other, but the three-longitudinal-grooves-pattern with the through-type transverse grooves, compared with the four-longitudinal-grooves-pattern with the through-type transverse grooves, is far better. As for the capability of water-expulsion, the hydroplaning velocity of the four-longitudinal-grooves-pattern is 105km/hr, which is better than the V-shaped pattern, 101km/hr, and the 人-shaped pattern, 104km/hr, but the normal contact force of the four-longitudinal-grooves-pattern decreases too much in low and medium velocity, so the 人-shaped pattern is considered as a more reliable one among these patterns.