Study On The Safety Problem Of Aircarft In Landing On Wet-pollution Pavement Considering Unbalanced Friction

The unbalanced friction degree of pavement caused by water film in rainy day has a significant impact on aircraft landing safety,it mainly involves two aspects of aircraft tire hydroplaning and the change of aircraft taxiing attitude.For aircraft wheel set hydroplaning,the wet pavement changes the state of interaction between aircraft tire and the pavement,reducing the aircraft's anti-skid performance;for the change of the taxiing attitude of the aircraft,the unbalanced pavement friction will affect the normal taxi attitude of the aircraft and cause the aircraft to deflect laterally.In allusion to these problems,theoretical analysis and numerical simulation were adopted to study in this paper.Firstly the features of the wet pavement that cause unbalanced pavement friction were studied.Then,the interaction between the aircraft tire and the wet pavement and the frictional resistance of the wet pavement were studied,by establishing a refined finite element model for the hydroplaning of aircraft wheel sets.Finally,the influence of friction unbalance conditions on the landing taxiing attitude of the aircraft was studied by establishing the ADAMS dynamic analysis model of the aircraft taxiing,based on the above analysis results.The main research contents are as follows:(1)The critical water film thickness theoretical model was established based on the analysis of the aircraft tire hydroplaning mechanism,and analyzed the critical water film thickness under different aircraft models and landing attitudes by using the theoretical model;(2)The stressing characteristics of aircraft tire under unbalanced friction degree condition were analyzed,and the main factors affecting the change of aircraft taxiing attitude under unbalanced friction degree condition were analyzed by establishing the cornering theoretical model of aircraft taxiing.(3)Based on the critical water film thickness theoretical model,establishing a refined finite element model for the hydroplaning of aircraft wheel sets by using ABAQUS,and verified the rationality of the model.(4)The interaction of aircraft tire-pavement-water film under different water film thickness was analyzed,and the influence of water film thickness on the friction characteristics of pavement was further analyzed.(5)A dynamic analysis model of the aircraft taxiing was established in a modular way by using ADAMS.Furthermore,the continuous unbalanced friction pavement model and the intermittent unbalanced friction pavement model were established,based on the above-mentioned research results of the water film thickness and pavement friction performance.(6)The influence of unbalanced friction degree conditions on the aircraft landing taxiing attitude was analyzed,and the yaw angles and distance were obtained.The safety risk of landing and taxiing of aircraft on the unbalanced friction pavement in rainy days was evaluated,based on the above models and research results.