飞机牵引滑行工况下前起落架疲劳寿命仿真分析

Simulation analysis of nose landing gear fatigue life under aircraft towing taxiing condition

为使机场运行更加高效经济,提出一种由牵引车将飞机高速牵引滑行至跑道起飞端的新模式。在牵引滑行工况下,前起落架要承受长时间长距离的高速重载荷牵引,同时受牵引车的加速和制动特性的影响,可能导致前起落架疲劳寿命降低。于是,针对飞机前起落架在该工况下的载荷分析以及疲劳寿命验证十分重要。通过Adams软件建立多体动力学模型,模拟真实工况,对不同牵引滑行速度下的牵引车-飞机系统仿真,获取到前起落架的载荷谱信息。结合前起落架有限元模型静力学分析和载荷谱,通过频域寿命分析法,在nCode软件中计算得到前起落架的疲劳寿命。结果表明,高速牵引滑行工况产生的大载荷加剧前起落架疲劳损伤,疲劳损伤从减震支柱凸耳向下阻力臂延展,疲劳寿命缩短3个数量级,需要对前起落架下阻力臂进行结构优化。本文中的研究可以为新牵引滑行模式下前起落架的疲劳寿命结构优化提供参考。

To make airport operations more efficient and cost-effective,a new mode is proposed where aircraft is high-speed towed to the takeoff end of the runway by tow tractors.Under this towing taxiing condition,the nose landing gear is subjected to long-duration,high-speed loads during towing,and is also influenced by the acceleration and braking characteristics of the tow tractor,which may lead to reduced fatigue life.Therefore,it is crucial to analyze the load distribution and verify the fatigue life of the nose landing gear under this condition.Using Adams software,a multibody dynamics model is established to simulate real operating conditions,and the load spectrum of the nose landing gear is obtained by simulating the tow tractor-aircraft system at different towing speeds.Combining the finite element model of the nose landing gear with static analysis and load spectrum,the fatigue life of the nose landing gear is calculated using the frequency domain fatigue analysis method in nCode software.The results indicate that the large loads generated during high-speed towing taxiing intensify fatigue damage in the nose landing gear,and the fatigue damage propagates from the strut ears to the drag brace,resulting in a three-order reduction in fatigue life.Structural optimization of the drag brace of the nose landing gear is required.This research provides valuable reference for the fatigue life and structural optimization of the nose landing gear under the new towing taxiing mode.