跑道不平整激励下飞机滑跑动载分析

Aircraft taxiing dynamic load induced by runway roughness

为探究跑道不平整状态和滑跑速度对飞机滑跑动载的影响规律,利用ADAMS/Aircraft软件建立了B737-800的虚拟样机模型,采用功率谱密度重构跑道不平整,进行了飞机多工况匀速滑跑仿真,并根据道面不平整方差与功率谱密度间的关系推导了最大动载系数预估方程。结果表明:不平整指数C和频率指数w的增大,均会引起动载系数变异性和最大动载系数的增大;最大动载系数随不平整指数C的增长速度逐步减小,而随频率指数w的增长速度呈现逐步增大的趋势;受升力和不平整激励的共同作用,最大动载系数随滑跑速度增加先增大后减小,出现极值和相应的敏感速度;敏感速度随着C和w的增大而增大,受w的影响更为显著;建立的飞机滑跑最大动载系数预估方程与仿真数据相关性很好(R^(2)>0.93),大部分实测机场跑道(C=0~0.4,w=2.0~2.6)的敏感速度最高为150.4 km/h,最大动载系数可达1.163。

In order to explore the effect of runway roughness and taxiing speeds on dynamic loads,ADAMS/Aircraft software was used to establish a virtual prototype model of B737-800,reconstructed runway profiles by the power spectral density method and simulated multiple conditions with a constant speed.Finally,a prediction equation of the maximum dynamic load coefficient was developed based on the relationship between the variance of runway roughness and the corresponding power spectral density.Results show that the increase of unevenness index(C)and waviness(w)increases the maximum dynamic load coefficient and the variability of dynamic load coefficient.Once the unevenness index(C)increases to a certain level,the maximum dynamic load coefficient tends to be flat out,while the maximum dynamic load coefficient increases faster with the increase of waviness(w).With the combined effects of runway roughness and lift force,the maximum dynamic load coefficient first increases and then decreases,resulting in an extremum and a corresponding sensitive velocity.The sensitive velocity increases with the increase of the unevenness index(C)and waviness(w),and the effect of waviness(w)is more significant.The proposed prediction equation has a good correlation with the simulation results(R^(2)>0.93),and for most of the measured runways(C=0-0.4,w=2.0-2.6),the sensitive velocity is up to 150.4 km/h and the maximum dynamic load coefficient is 1.163.