Study of Time-Varying Effects of Nonlinear Shock Strut on Towbarless Traction Dynamics

A novel towbarless towing-out mode has emerged as a promising sustainable and efficient solution for ground operations of heavily loaded civil aircraft. The shock strut, a critical energy-absorbing component connecting the nose landing gear to the aircraft body, induces complex nonlinear time-varying effects that can significantly influence the dynamic response of the traction system. In this paper, the nonlinear time-varying dynamics of the high-speed, heavy-load traction system are thoroughly examined. A dynamic model considering the time-varying effects is first established, which is rigorously validated by building an experimental platform based on a real aircraft’s nose landing gear. The dynamic response with time-varying effects is then studied, and responses when crossing pits with different depths are evaluated. The findings reveal that accounting for time-varying effects is crucial for reflecting the system’s dynamic behavior under specific runway conditions. Time-varying stiffness notably influences the lower-order modes and the system’s response, particularly at the pit edges. This study provides guidance for accurately assessing the dynamic performance of the traction system and contributes to the overall safety and efficiency of airport operations.