湿滑道面飞机轮胎临界滑水速度数值仿真

采用ABAQUS建立了基于CEL算法的飞机轮胎与积水道面流固耦合分析模型, 推导了轮胎接触面动水压强与道面竖向支撑力表达式, 对比了飞机起飞与着陆过程中的滑行状态, 提出了临界滑水速度的上下限解概念, 校核了轮胎模型静态变形与动态滑水特征, 研究了胎压、胎纹与水膜厚度的影响规律, 分析了轮胎接地面积与动水压强分布。仿真结果表明: 在76.6kN轴载作用下, 轮胎模型接地面积为0.076m2, 轮胎中心竖向变形约为3.27cm, 轮胎临界滑水速度为128.5~222.4km·h^-1, 与NASA轮胎滑水试验数据一致, 验证了仿真模型的合理性和适用性; 在胎压为1 140kPa时, 减速冲击条件下飞机轮胎临界滑水速度为163km·h^-1, 小于加速冲击时的上限226km·h^-1, 轮胎接地面积明显减小, 道面支撑力低于机轮轴载的10%;在450~1 109kPa胎压范围内, 减速冲击时临界滑水速度下限较NASA经验公式计算结果更为保守, 两者相差30⁷0km·h^-1; 轮胎纵向沟槽排水可降低轮胎前缘动水压强峰值, 增大轮胎接地面积, 减速冲击时带纹轮胎临界滑水速度较光滑轮胎提高了26.9%~28.8%, 增幅约为加速冲击时的2倍; 当道面水膜厚度由3mm增加至13mm时, 胎压为1 140kPa的飞机轮胎临界滑水速度上下限分别降低了85km·h^-1和43km·h^-1; 在低胎压、厚水膜与减速冲击条件下, 临界滑水速度下限仅为127km·h^-1, 低于常见飞机进近接地速度205~250km·h^-1, 因此, 滑水事故风险增加。

Numerical simulation of critical hydroplaning speed of aircraft tire under wet pavement condition

A fluid-solid coupling analysis model of aircraft tire and wet pavement based on CEL algorithm was developed by using ABAQUS.The expressions of hydrodynamic pressure of tire contact and vertical supporting force of pavement were derived.The taxiing conditions between aircraft take-off and landing process were compared.The concepts of upper and lower limit solutions of critical hydroplaning speed were proposed.The features of static deformation and dynamic hydroplaning of tire model were verified.The influence rules of tire pressure, tire pattern and water-film thickness were discussed. The contact area and distribution of hydrodynamic pressure for tire were analyzed.Simulation result indicates that the tire contact area is0.076 m2 under axle load of 76.6 kN, the vertical deformation at the centre of tire is 3.27 cm, and thecritical hydroplaning speed is 128.5-222.4 km·h-1, which is in consistence with the result of NASA's tire hydroplaning test.Therefore, the rationality and feasibility of simulation model are proved.When tire pressure is 1 140 kPa, the critical hydroplaning speed of aircraft tire under decelerating impact is 163 km·h-1 and lower than upper limit of accelerating impact (226 km·h-1), the tire contact area obviously reduces, and the supporting force from the pavement to the tire is less than 10% of wheel load.In comparison with the calculation result of NASA's empirical equation, the lower limits of critical hydroplaning speed under decelerating impact are more conservative within the scope of tire pressure from 450 kPa to 1 109 kPa, and the difference is30-70 km·h-1.The drainage effect of radial tire pattern can reduce the peak value of hydrodynamic pressure at the leading edge of aircraft tire and increase the tire contact area.The critical hydroplaning speed of aircraft tire with tire pattern under decelerating impact increases by26.9%-28.8% comparing with the speed of smooth tire, and the amplification is twice as much as that of accelerating impact.As the water-film thickness increases from 3 mm to 13 mm, the upper and lower limits of critical hydroplaning speed of aircraft tire respectively reduce by 85 km·h-1 and 43 km·h-1 when the tire pressure is 1 140 kPa.In case of lower tire pressure and thicker water-film, the lower limit of critical hydroplaning speed is merely 127 km·h-1 under decelerating impact and lower than most aircrafts'landing speeds 205-250 km·h-1, so the risk of hydroplaning accident increases.