道面平整度对湿滑道面-飞机轮胎相互作用影响分析

Analysis of the Influence of Pavement Roughness on Wet Pavement and Aircraft Tire Interaction

湿滑条件下,跑道不平整使积水厚度随道面起伏而变化,影响飞机起降安全。因此,引入国际平整度指数(international roughness index,IRI),搭建基于IRI的轮胎-积水-道面有限元模型,通过仿真模拟,分析不同IRI的道面对飞机临界滑水速度的影响;结合IRI,对比不同飞机轮胎速度、积水厚度条件下道面视摩擦因数较平整道面的降低幅度,分析IRI对道面摩擦性能的影响;并依据某机场视摩擦因数实测试验结果,对仿真实验结果进行修正,探究IRI对飞机刹车效应的影响。结果表明:道面平整段积水厚度一定时,飞机临界滑水速度随IRI增加而降低,当IRI=5时,飞机临界滑水速度较平整道面降低约30%;飞机轮胎速度一定时,视摩擦因数随道面平整度等级降低而减小,当IRI=5时,视摩擦因数较平整道面降低幅度高达98%,严重影响飞机运行安全;道面平整度等级为“好”时,相同平整度段积水厚度下,飞机轮胎与道面视摩擦因数随IRI的增加而减小;综合考虑IRI和经试验数据修正后的视摩擦因数对飞机刹车效应产生的影响发现,随着平整度指数与平整段积水厚度逐渐增加,飞机刹车效应会产生降级。国内某机场道面在1.5<IRI≤2,平整段积水厚度≥7.66 mm的道面条件下,飞机刹车效应最大降低了3级,即由“中到差”降至“差”,此时飞机方向操纵与减速能力严重下降;积水道面平整度评价为“中”和“差”时,飞机刹车效应降级幅度突增,导致道面条件无法保障飞机运行安全;平整段积水厚度为7.66~13 mm时飞机刹车效应受IRI变化的影响较大,降级变化明显,在维护过程中须尤为注意。

Under slippery conditions,the thickness of accumulated water is affected by uneven runways and changed by the fluctuation of the road surface,and the safety of aircraft take-off and landing is also affected.Therefore,the international flatness index(IRI)was introduced to build a tire-water-pavement finite element model based on the IRI.Through simulation,the influence of different IRI indexes on the critical hydroplaning speed of aircraft was analysed.Combined with IRI index,the reduction range of apparent friction coefficient of pavement with different tire speed and accumulated water thickness was compared,and the influence of IRI on pavement friction performance was analysed.According to the experimental results of apparent friction coefficient of an airport,the simulation results were modified to explore the influence of the IRI on aircraft braking effect.The results show that when the thickness of accumulated water in the pavement levelling section is constant,the critical water skiing speed of aircraft is reduced by the increase of IRI,and it is reduced by about 30%compared with the flat pavement when IRI=5.When the speed of the aircraft tires is constant,the apparent friction coefficient of the pavement is decreased by the decrease of the level of the pavement smoothness.When IRI=5,the apparent friction coefficient of the pavement is reduced by as much as 98%compared with the smooth pavement,which seriously affects the safety of the aircraft operation.When the road surface smoothness grade is“good”,under the same thickness of accumulated water in the pavement levelling section,the apparent friction coefficient between the aircraft tire and the road surface is decreased by the increase of the IRI.Considering the influence of the IRI index and the apparent friction coefficient corrected by the test data on the braking effect of the aircraft,it is found that the braking effect of the aircraft will be degraded with the gradual increase of the flatness index and the thickness of accumulated water in the pavement levelling section.Under the conditions of a domestic airport pavement with 1.5<IRI≤2 and the thickness of accumulated water in the pavement levelling section≥7.66 mm,the braking effect of the aircraft is reduced by a maximum of 2 grades,that is,from“good to medium”to“medium to poor”,at this time the aircraft directional control and deceleration capabilities are decreased.When the flatness of the water surface is evaluated as“medium”or“poor”,the degradation of the aircraft braking effect is increased suddenly,and the pavement surface conditions cannot be guaranteed the safety of aircraft operation.And when the thickness of accumulated water in the pavement levelling section is 7.66~13 mm,the braking effect of the aircraft is greatly affected by the change of the IRI,and the degradation is changed obviously,so special attention should be paid during the maintenance process.